Hyp3 PROJECT Pattern, Process, and Productivity in Hypermaritime Forests of Coastal British Columbia 2005 a SYNTHESIS of 7-YEAR RESULTS

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SPECIAL REPORT

 THE HyP3 PROJECT Pattern, Process, and Productivity in Hypermaritime Forests of Coastal British Columbia 2005 A SYNTHESIS OF 7-YEAR RESULTS

Ministry of Forests Forest Science Program The HyP3 Project Pattern, Process, and Productivity in Hypermaritime Forests of Coastal British Columbia

A Synthesis of 7-Year Results

Compiled & Edited by: Allen Banner, Phil LePage, Jen Moran, & Adrian de Groot

Ministry of Forests Forest Science Program The use of trade, ﬁrm, or corporation names in this publication is for the information and convenience of the reader. Such use does not constitute an ofﬁcial endorsement or approval by the Government of British Columbia of any product or service to the exclusion of any others that may also be suitable. Contents of this report are presented as information only. Funding assistance does not imply endorsement of any statements or information contained herein by the Government of British Columbia.

Library and Archives Canada Cataloguing in Publication Data Main entry under title: The HyP3 Project : pattern, process and productivity in hypermaritime forests of coastal British Columbia : a synthesis of 7-year results (Special report series,  0843-6452 ; 10) Includes bibliographical references: p.  0-7726-5320-8 1. Forest ecology - British Columbia - Pacific Coast. 2. Sustainable forestry - British Columbia - Pacific Coast. 3. Forest management - British Columbia - Pacific Coast. 4. Forests and forestry - British Columbia - Pacific Coast. I. Banner, Allen, 1954- . II. British Columbia. Forest Science Program. II Series: Special report series (British Columbia. Ministry of Forests) ; 10. 106.2.737 2005 333.75'09711 2005-960066-7

Citation: Banner, A., P. LePage, J. Moran and A. de Groot (editors). 2005. The HyP3 Project: pattern, process, and productivity in hypermaritime forests of coastal British Columbia – a synthesis of 7-year results. B.C. Min. For., Res. Br., Victoria, B.C. Spec. Rep. 10.

Prepared by Allen Banner, R.P.Bio., R.P.F. Research Ecologist, B.C. Ministry of Forests Smithers, BC   Phil LePage, R.P.F. Research Silviculturist, B.C. Ministry of Forests Smithers, BC   Jen Moran B.C. Ministry of Forests Smithers, BC   Adrian de Groot, R.P.Bio. Drosera Ecological Consulting Smithers, BC  

Copies of this report may be obtained, depending upon supply, from: Crown Publications 521 Fort Street, Victoria, BC   (250) 386-4636, www.crownpub.bc.ca

For more information on Forest Science Program publications, visit our web site at: http://www.for.gov.bc.ca/hfd/pubs/index.htm

ii CONTRIBUTING AUTHORS

British Columbia Ministry of Forests Allen Banner (project leader), Marty Kranabetter, Phil LePage, Dave Maloney, Karen McKeown, Jen Moran, Jim Pojar1

University of Waterloo Ramon Aravena, Taro Asada, Lisa Emili, Dan Fitzgerald, Chris Gainham, John Gibson, Sandra Lortie, Jonathan Price, Barry Warner

Consultants Shauna Bennett (Bio Logic Consulting), Davide Cuzner (Viking Ecosystem Consultants), Adrian de Groot (Drosera Ecological Consulting), Colleen Jones (Shamaya Consulting)

1 Now afﬁliated with the Canadian Parks and Wilderness Society, Whitehorse, Yukon.

iii EXECUTIVE SUMMARY

The HyP3 Project (pronounced “hip Chapters 1 and 2 provide the back- cubed”) was initiated in 1997 to provide ground to the research, including a review an integrated research approach to the of previous studies. These chapters also study of pattern, process, and productivity present descriptions of the north coast in the hypermaritime forests of north landscape and the specific study areas, coastal British Columbia. The project has stand types, and ecosystems targeted for four main goals: the research. The geographic scope of the • Document the ecology of the blanket project encompasses the Coastal Western bog–upland forest complex of north Hemlock zone, Very Wet Hypermaritime coastal British Columbia. subzone, Central variant (CWHvh2) with- • Assess the feasibility of managing poor- in the North Coast and North Island– and low-productivity cedar–hemlock Central Coast forest districts of the Coast forests, which dominate the outer Forest Region. The blanket bog–upland coastal landscape, for timber and fibre forest complex of the CWHvh2 contains production. approximately 235 000 ha of lower-pro- • Define the extent of these sites and ductivity cedar-dominated stands that identify the potentially operable por- straddle the defined operability thresholds tion. for height class, merchantable volume, • Develop ecologically based manage- and site limitations. As market values for ment guidelines for these forests. redcedar and yellow-cedar improve, pres- The need for this research was made sure increases to alter the operability clear in the 1995 timber supply review for thresholds. This has already begun to the North Coast Timber Supply Area. occur on the north coast, and because this This report stated that the Chief Forester research is now under way, preliminary required better scientific information management guidelines can be in place before he would consider expanding the before operability pressures increase dra- operable land base into lower-productivity matically. From an ecological perspective, cedar-dominated (western redcedar [Thuja the outer coast of British Columbia is a plicata] and yellow-cedar [Chamaecyparis fascinating landscape and a major thrust nootkatensis]) forests. Research was re- of the research is simply to gain a better quired that would address basic ecosystem ecological understanding of these hyper- function (e.g., watershed and soil hydrolo- maritime forests and wetlands. gy, plant and soil ecology, succession and Chapter 3 describes studies of site and stand dynamics) and provide practical watershed hydrology and biogeochem- management guidelines for these forest istry. Water plays a pivotal role in shaping types. ecosystem function on the outer coast, This report presents a synthesis of the and thus hydrological studies are an HyP3 Project’s 7-year results. It provides important part of the HyP3 Project. To an overview of the project to date and produce water budgets for small water- summarizes initial results for each of the sheds and predict the potential effects of project components—hydrology and bio- timber harvesting on these water budgets, geochemistry, ecosystem processes, classi- watershed-level studies included moni- fication and inventory, and operational toring of precipitation, interception, trials. The report concludes with a chapter throughfall, and streamflow. Site-level on management interpretations. studies examined water table dynamics,

iv hydrological linkages between sites, and Hydrological dynamics differ among natural soil drainage mechanisms such as forest types. Our study indicates that the soil pipes. Soil water chemistry across the cedar-dominated upland scrub forests spectrum of forest and bog ecosystems in (i.e., the target stands of the HyP3 Project; the CWHvh2 is also characterized. CWHvh2/01 sites) will likely have an on- Hypermaritime watersheds of the site hydrological response to harvesting CWHvh2 have a relatively low water stor- that is intermediate between the wetter age capacity. The shallow, dominantly swamp forests and the more productive organic, soils typical of these watersheds upland forests. Water tables are likely to have high water retention capacity, and rise slightly depending on specific site and are frequently saturated in this wet cli- soil characteristics. Compared with the mate. The small amount of available water upland scrub forests, the true swamp storage capacity in these soils means that forests are quite restricted in distribution significant runoff is generated from rela- on the coast. The swamps are more sensi- tively small storms. Compared with other tive to harvesting-induced hydrological locations, rainfall events in the CWHvh2 changes than upland forests; they should produce a larger hydrological response. not be harvested because of their impor- The decrease in canopy interception tance in receiving water and regulating after harvesting increases the amount of streamflow within a watershed, and their water received on the ground. At the greater potential for rising water tables. HyP3 study sites, the canopy intercepted Where scrub forests occur on flat or very 20–25% of the average annual rainfall. If gently sloping sites, a rise in the water these areas are clear-cut, the amount of table following timber harvesting is water requiring removal by existing expected and could have negative ecologi- hydrological processes can be expected to cal implications. Smaller rainfall events increase. The possible hydrological conse- would saturate these forest soils because quences of these increased water inputs of the reduced interception and transpira- include faster development and increased tion following canopy removal. This may volume of peak flows, higher water tables, hamper regeneration and promote paludi- and increased erosion resulting from fication, with the invasion of sphagnum overland flow. mosses and other wetland plants. As Organic soils (especially on disturbed forests regenerate, canopy interception sites) have high water retention and low and transpiration begin to increase again, cohesion qualities, and therefore the pos- but the time required for hydrological sibility of increased erosion must be con- recovery is still uncertain in this hyper- sidered. The relatively gentle slopes on maritime environment. Long-term moni- which these low-productivity forests toring of current and future operational occur, however, will result in lower sur- trials will help answer this question. face water runoff velocities, and thus High water tables and high levels of lower off-site sediment transport than on acidity limit nutrient availability by steeper hillslopes. Using the current restricting rooting depth and maintaining watershed assessment procedures for road anaerobic soil conditions that prevent the building and bridge engineering, the man- oxidization of nutrients to available agement of additional water to a drainage forms. Our study shows that the highest system is possible. By knowing the har- ion concentrations in soil water occur in vested area and the watershed’s discharge well-drained (productive forest) vegeta- characteristics, the potential increase in tion types, which have deeper water tables peak flows can be identified and account- and thicker aerobic zones. ed for in management plans.

v Naturally formed soil pipes play an Production and decomposition rates with- important role in draining forests in the in present-day vascular plant and moss hypermaritime north coast. Soil pipes communities were measured to estimate transport stormflow rapidly and efficient- current rates of accumulation. These stud- ly; however, if harvesting damages these ies included detailed measurements of pipes, they could become “short-circuited,” annual sphagnum moss productivity and decreasing their capacity to route storm- colonization on both disturbed and undis- flow through the landscape. turbed sites. After harvesting, dissolved organic car- HyP3 research also included studies of bon () levels could increase along bedrock, soil property, and site productiv- with the greater water inputs to a site. If ity relationships in both old-growth and  increases a large amount after har- second-growth stands across the spectrum vesting, water quality can be affected. of site series, from bog woodland and Some evidence from southeast Alaska scrub forest to productive upland forest. suggests, however, that peatland streams From these ecosystem process studies, are better adapted to handle an increase a simple model of ecosystem development of  after harvest than the non-peat- in the CWHvh2 has emerged. In this model, land systems. The non-peatland systems three main factors operate in combination are thus more susceptible to changes in to drive ecosystem development and pro- stream biology resulting from increased ductivity in this hypermaritime environ-  inputs after harvest. Future opera- ment: tional trials in lower-productivity western 1. bedrock geology redcedar–hemlock forests should include 2. soil drainage a soil water monitoring program. Such a 3. disturbance history program could better quantify changes in Although these same factors influence water table levels and  and ion con- ecosystem development to some degree in centrations in soil and stream waters asso- most other terrestrial environments, their ciated with harvesting. influence is especially dramatic in the Chapter 4 describes studies of ecosys- CWHvh2. tem processes, including disturbance and The scarcity of glacial till in this coastal ecological succession, vegetation dynam- environment highlights the importance of ics, production and decomposition, nut- bedrock geology. Most soils develop direct- rient cycling, and other aspects of soil ly from the weathering of bedrock or col- ecology. Organic matter dynamics, luvial material. This contrasts with many including rates of forest humus and peat other areas where a mantle of glacial till accumulation, is an important ecosystem of mixed lithology masks the influence of process on the outer coast, where organic bedrock. In addition, sharp contrasts in soil layers play a vital role in determining bedrock type occur on the outer coast, successional trends and site productivity. from the hard, slowly weathering grano- The many peatlands that characterize diorites with relatively low amounts of the coastal landscape preserve a record of available nutrient elements, to the much past conditions in their pollen and macro- softer, easily weathered metamorphic fossil profiles. These profiles provide the rocks and limestone with more nutrient- data against which we can compare cur- rich lithologies. These different bedrock rent conditions, and predict future hydro- types manifest themselves in dramatic dif- logical and related ecosystem responses to ferences in plant communities and forest natural and human-influenced disturbances. productivity. Core sampling at several sites was con- Excess soil water is the rule in this ducted to reconstruct historical vegetation hypermaritime environment, and subtle patterns and rates of peat accumulation. variations in slope or internal soil

vi drainage result in significant differences studies, a switch in biomass allocation in forest productivity. In contrast to from trees to mosses (and other under- the majority of other subzones in the storey vegetation) occurs as sites paludify province (where moisture deficits are and tree productivity declines. Bogs and common), the most freely drained sites bog forests are often referred to as “low in the CWHvh2 are the most productive productivity.” They are, however, highly sites for trees. Even these “drier” sites are productive if one considers the annual fresh to moist in absolute terms, and as rates of total biomass accumulation in long as soil water is moving, rather than these ecosystems. stagnant, tree productivity will remain Chapter 5 presents the classification moderate to high. and inventory component of the HyP3 The tendency for organic matter to Project, which serves as the link between accumulate on sites that have not been the hydrology and ecosystem process disturbed by landslides, windthrow, or components and the application of results fluvial disturbances for hundreds (or across the north coast. The project has thousands) of years is also dramatic in used the Biogeoclimatic Ecosystem the CWHvh2. As soil organic matter accu- Classification () system as the frame- mulates, soils become wetter and tree work to make ecologically based forest roots become more confined to surface management recommendations.  uses organic horizons. Although the nutrient the site series to classify forests for man- capital in these organic horizons is consid- agement purposes. Ecosystem classifica- erable, nutrient availability is relatively tion is invaluable for choosing appropriate low because of the wet, acidic conditions sites for in-depth studies, and for extrapo- and low rates of nitrogen mineralization. lating the results to other similar sites on Better-drained sites, which often have a the north coast. history of natural disturbance, especially We conducted sampling to collect where soil organic and mineral horizons baseline information on tree growth and are mixed, exhibit higher forest produc- site productivity throughout the range of tivity. forested site series in the CWHvh2. These Although models are inherently sim- data show that estimates of site productiv- plistic, ecosystem development and forest ity from old-growth stands significantly productivity on the majority of sites on underestimate second-growth site poten- the outer coast are largely driven by tial. On CWHvh2/01 (upland scrub forest) bedrock geology, soil drainage, and dis- sites, for example, western redcedar site turbance history working in combination. index at breast height age 50 years, aver- The model presented in Chapter 4 can ages 18 m in second-growth stands, but also be used to guide forest management estimates of 10 m or less are derived from investments and activities, and to help old-growth stands. Past timber supply define and understand the limits of oper- analyses have used the old-growth pro- ability in the CWHvh2. For example, ductivity estimates from the forest cover marginally productive sites occurring on inventory database to model the growth metamorphic rock will exhibit higher sec- and yield of regenerating stands. This sug- ond-growth productivity following har- gests that potential yields of second-growth vesting and site treatments compared CWHvh2/01 sites, as well as other current- with a similar site on granodiorites. ly operable sites, are underestimated. HyP3 Two variations of the model are pre- results clearly indicate that second-growth sented—one emphasizing forest produc- productivity of these scrub forests is high tivity, and one emphasizing biomass enough to consider them as potentially allocation. As indicated by the soil ecolo- operable, subject to the assessment of gy, moss productivity, and succession other site limitations.

vii At each of the HyP3 study sites, timber soil mixing and mounding, improves cruising was carried out to quantify stand regeneration success and tree growth and structure, species composition, and gross nutrition on poor cedar–hemlock sites. and merchantable volume. Several forest Care must be taken, however, to avoid mensuration attributes are summarized creating conditions (e.g., pools beside from these data for each of the CWHvh2 mounds) that facilitate sphagnum moss site series studied. Rare, or otherwise growth and paludification. Monitoring of threatened or imperiled ecosystems of the planted and natural regeneration, as well CWHvh2 are also reviewed to examine as moss and vascular plant succession, at the potential effects of expanding forestry this site will continue into the future. operations into the lower productivity Block layout, harvesting, site treatments, forest types. planting, and initial regeneration surveys A predictive ecosystem mapping () are complete at the Oona River trial. model was developed for the outer coast. Planted western redcedar survival and The resulting maps identify the site series growth results are very encouraging and most likely associated with each forest reinforce the belief that CWHvh2/01 sites cover polygon. These maps help to estab- have significant forest management lish the extent and location of potentially potential. Long-term monitoring of this operable low-productivity cedar–hemlock trial will take place to ensure that early forest types. Site series productivity data trends continue and management inter- can also be combined with these maps to pretations remain current and realistic. aid in growth and yield analysis. Chapter 7 presents management inter- Chapter 6 describes the HyP3 opera- pretations resulting from the first 7 years tional research trials at Port Simpson and of HyP3 research and operational trials. Oona River. The trial near Port Simpson, The HyP3 Project focuses primarily on the north of Prince Rupert, was established in ecological and operational feasibility of 1990 to examine second-growth produc- sustainable forest management practices tivity in the poor cedar–hemlock forest on the CWHvh2/01 sites. The economics type. Initially funded by South Moresby of the operations were not examined Forest Replacement Account () because the value of western redcedar is research funds, this study was taken over quite variable, and subtle changes will sig- by the HyP3 Project in 1999. The Port nificantly affect the economic viability of Simpson trial focused on the effect of managing these sites. mounding on the survival and growth of Low-productivity sites in the CWHvh2 planted seedlings and on some of the eco- belong primarily to the Western redcedar logical impacts of site treatments. The – Western hemlock – Salal site series Oona River operational trial is located on (CWHvh2 /01). These sites typically have Porcher Island, south of Prince Rupert. between 200 and 300 m3/ha merchantable This is a more expansive trial and was volume. The vast majority of these sites established in 1998 to test some of the are currently outside the operable land management ideas gained from both base. At the upper end of the productivity the Port Simpson trial and the multi- spectrum for these site series, soil and veg- tude of research studies undertaken on etation conditions become transitional to CWHvh2/01 sites around Prince Rupert. the Western hemlock – Sitka spruce – The Oona River trial examines several Lanky moss site series (CWHvh2/04), ecological and operational aspects of for- which is currently included in the opera- est management activities on the low- ble land base (merchantable volumes typi- productivity cedar–hemlock sites. cally greater than 400 m3/ha). At the Results from the Port Simpson trial lower extremes of productivity for the suggest that site preparation, including CWHvh2/01 site series, conditions are

viii transitional to the Western redcedar – soil horizons, bedrock geology, overstorey Yellow-cedar – Goldthread site series and understorey composition, and stand (CWHvh2/11), in which merchantable volume. Other information, such as loca- wood volumes (typically less than tion and access, should be used in combi- 150 m3/ha) are well below current nation with these site factors to determine and projected operability limits. overall operability on a site-specific basis. Historical ecosystem classification data We will further refine these operability were used to develop better descriptions criteria as we gain more experience in of these hypermaritime ecosystems, espe- these forest types. cially for the lower-productivity forest Specific recommendations are provided types of interest in this study. By combin- on block layout, harvesting methods, site ing this information with HyP3 Project preparation treatments, and planting on results, we have defined a set of criteria to CWHvh2/01 sites. Chapter 7 concludes identify those CWHvh2/01 sites with the with a summary of the future research greatest potential for sustainable forest required to further develop and test our management. These criteria include: current management recommendations depth and nature of mineral and organic for these hypermaritime ecosystems.

ix ACKNOWLEDGEMENTS

As the list of contributing authors indi- Pacific Cannery, our field headquarters cates, the success of HyP3 Project and the for the early years of the study. The staff production of this synthesis report result- at the North Coast Forest District, espe- ed from the dedicated, co-operative work cially Mike Grainger, Marc Bossé, and of many individuals over the past 8 years. Czeslaw Koziol, are recognized for their The compilers and editors are greatly logistical support. Davide Cuzner, former- indebted to all of the contributing authors ly with the North Coast Forest District, who co-ordinated and carried out specific was a key member of the HyP3 team from components of the HyP3 Project and con- its inception, and co-ordinated or assisted tributed to various chapters of this report. with many aspects of the project. His In addition, the following individuals unending enthusiasm for the work was an played important roles in various stages inspiration for everyone. Karen McKeown of the field work, logistics, data analysis, has been, for many years, the “glue” that and final reporting. holds our Forest Service research team in Colleen Jones provided organizational Smithers together and her positive out- and administrative support during the look and willing assistance with all aspects early years of the project. Gordon Kayahara of this project are greatly appreciated. and Christine Chourmouzis co-ordinated The establishment of our operational and carried out the stand reconstruction trial at Oona River would not have been studies in the early years of HyP3. Patrick possible without the dedication and assis- Williston and Karen Golinski planned and tance of many members of the extended conducted the assessment of lichen and Bergman family. At Oona River, we were bryophyte diversity at the Oona River trial afforded an excellent opportunity to meld site. Over the duration of the project, field science with operations, and the keen par- assistance was provided on various study ticipation and assistance of the Bergmans components by: Shauna Bennett, Bruce made this opportunity a reality. Their Catton, Dave Coates, Danielle Cobbert, expertise, diverse local knowledge, and Leah Cuthbert, Pauline Favero, Karen historical perspective were invaluable to Geertsema, Sarah Graham, Marcel Lavigne, the success of the project. To Johnny, Will MacKenzie, Michelle McGibbon, Karl, David, their families, and the many Rob Meisner, Kelli Ohland, Penny Olanski, other Oona River residents that helped Mike Oiser, Larissa Puls, Dave Redman, make our field studies there rewarding, Dave Spittlehouse, Victoria Stevens, fun, and fattening, we extend our sincere Sandra Thomson, Ted Turner, Sheila thanks. Vardy, Dave Wilford, Alex Woods, Colin Technical reviews of this report were Woolridge, Elaine Wright, and Tara Wylie. kindly provided by Bernard Bormann, These individuals all contributed to the Geoff Cushon, David D’Amore, Mike success of the project. Grainger, Paul Hennon, Paul Marquis, We thank the Lax Kw’alaams Band for Del Meidinger, Peter Ott, Chuck Rowan, their co-operation in establishing the Port and Larry Sigurdson, and we thank them Simpson operational trial, and Sally and for their helpful suggestions. English edit- Wilfred Knott and their family for the ing and proofreading was carried out by wonderful hospitality during our stays at Susan Bannerman, and typesetting and the village. page layout by Donna Lindenberg. We Thanks also go to Tony Duggleby, are grateful to Paul Nystedt and the Herb Pond, and the staff at the North Production Resources staff of the B.C.

x Ministry of Forests, Research Branch, in Ltd., Interpac Resources Ltd., and Victoria for co-ordinating the publication Triumph Timber Ltd., and the B.C. of this report. Ministry of Forests, Coast Forest Region. Forest Renewal BC provided funding We thank Denis Collins, Research for the first 5 years of this project. More Manager, Coast Forest Region, for his recently, funding was provided by the assistance in obtaining funding to support Province of British Columbia Forest the continuation and publication of this Investment Account, through the cooper- research. ation of International Forest Products

xi CONTENTS

Contributing Authors...... iii

Executive Summary ...... iv

Acknowledgements ...... x

1 Introduction ...... 1 1.1 The Issue ...... 1 1.2 HyP3 Research Approach ...... 4 1.3 Previous Studies: Historical Perspective...... 6

2 Location and Environmental Setting ...... 10 2.1 Location, Physiography, and Geology ...... 10 2.2 Climate...... 11 2.3 Vegetation, Soils, and Ecosystems ...... 12 2.4 Natural Disturbance Regimes ...... 15 2.5 Adjacent Biogeoclimatic Units...... 16 2.6 HyP3 Study Sites...... 16

3 Hydrology and Biogeochemistry ...... 19 3.1 Introduction ...... 19 3.2 Watershed Hydrology ...... 19 3.3 Soil Hydrology and Biogeochemistry...... 29 3.4 Discussion and Summary ...... 41

4 Ecosystem Processes ...... 47 4.1 Introduction ...... 47 4.2 Succession and Disturbance ...... 47 4.3 Paludification and Vegetation Dynamics ...... 51 4.4 Vegetation Types and their Dynamics: Discussion...... 66 4.5 Soil Ecology ...... 68 4.6 Model of Ecosystem Development and Productivity in the CWHvh2...... 80

5 Classification and Inventory ...... 82 5.1 Introduction and Approach...... 82 5.2 Site Series Descriptions...... 82 5.3 Site Productivity ...... 86 5.4 Forest Mensuration ...... 89 5.5 Biodiversity Considerations...... 94 5.6 Predictive Ecosystem Mapping ...... 101

6 Operational Research Trials...... 105 6.1 Introduction ...... 105 6.2 Port Simpson ...... 105 6.3 Oona River...... 109

7 Management Interpretations...... 118 7.1 Identification of Potentially Operable Sites ...... 118 7.2 Silvicultural Systems...... 118 7.3 Future Research Direction ...... 123

xii Glossary...... 127

References ...... 130



1 HyP3 Project-related Extension Notes...... 126



2.1 Climatic data for the CWHvh2 and some adjacent subzones...... 12 3.1 Total monthly rainfall by site and elevation, correlated to the North Pacific Cannery reference site at Port Edward ...... 23 3.2 Percentage of rainfall by wind direction ...... 25 3.3 Annual rainfall, throughfall, stemflow, and interception at the Smith Island and Diana Lake sites ...... 25 3.4 Maximum and minimum monthly interception as a percentage of rainfall at the Smith Island and Diana Lake sites ...... 25 3.5 Rainfall interception sorted by canopy condition, event intensity, and event length ...... 27 3.6 Production of stemflow by tree size class ...... 28 3.7 Water balance for the Smith Island and Diana Lake watersheds, 1998–2001...... 28 3.8 Average depth to water table, pH, and dissolved organic carbon of groundwater from mineral and organic soil horizons by site series...... 31 3.9 Characteristics of the S01 and K-pipe basins...... 34 3.10 Mean ionic composition of groundwater by site series at Diana Lake, 1997–1998 ...... 40 3.11 Mean ionic composition of groundwater in the organic and mineral subsoil horizons at Diana Lake, 1997–1998 ...... 40 3.12 Mean seasonal ionic composition of groundwater at Diana Lake, 1997–1998...... 40 4.1 Growth and production of sphagnum and other mosses and their correlation with climatic parameters ...... 52 4.2 Vegetation classified at the Diana Lake study site by two-way indicator species analysis ...... 55 4.3 Vegetation classified at the Port Simpson study site by two-way indicator species analysis...... 59 4.4 Estimated total net primary production for the five representative micro-communities in the open bog at the Diana Lake study site ...... 65 4.5 Mass loss of Sphagnum fuscum litter from litter bags incubated at 10 cm below ground surface for 1 year ...... 65 4.6 Total chemical concentrations for bedrock types ...... 69 4.7 Mean organic and mineral soil depths for CWHvh2 site series on the north and central coast of British Columbia...... 70 4.8 Mean organic and mineral soil depths for CWHvh2/01 and CWHvh2/04 site series by bedrock type on the north and central coast of British Columbia ...... 70 4.9 Average chemical properties of mineral soils, well-drained sites only ...... 70 4.10 Foliar nutrient concentrations for western hemlock, Sitka spruce, and western redcedar on productive sites of north coast British Columbia ...... 78

xiii 4.11 Average height increment for each tree species by soil moisture regime and bedrock type ...... 79 5.1 Old-growth and second-growth productivity data for the CWHvh2, north coast of British Columbia ...... 88 5.2 Summary of average stand characteristics for the CWHvh2/11, /01, and /04 site series at the Diana Lake, Oona River, and Smith Island study areas...... 89 5.3 Tree heights used for height class designations ...... 93 5.4 Summary of average stand characteristics for the CWHvh2/11 site series at the three study sites ...... 93 5.5 Summary of average stand characteristics for the CWHvh2/01 site series at the three study sites...... 93 5.6 Summary of stand characteristics for the CWHvh2/04 site series at the three study sites...... 94 5.7 Red- and blue-listed ecosystems of the hypermaritime mainland coast of British Columbia ...... 95 5.8 A comparison of foliicolous lichens and bryophytes from Porcher Island and those reported by Vitt et al. (1973) from other coastal localities in British Columbia ...... 101 6.1 Substrate descriptions at Port Simpson mounding trial ...... 106 6.2 Average percent survival and height of planted western redcedar seedlings at Oona River ...... 115 6.3 Cruised and call-graded merchantable timber volumes by log grade and species from the Oona River operational research trial ...... 116 7.1 Site identification criteria for determining operability of Western redcedar – Western hemlock – Salal (01) sites CWHvh2 ...... 119



1.1 North Coast Timber Supply Area, British Columbia, Canada...... 2 1.2 Harvested sites on highly productive steep slopes of the CWHvh2 subzone ...... 2 1.3 Distribution of the CWHvh2 within the North Coast Forest District...... 3 1.4 Landslide associated with mid-1980s road-building activities, coastal British Columbia ...... 4 2.1 Generalized bedrock geology, central and north coast of British Columbia ...... 11 2.2 Upland productive forest type, CWHvh2/06 ...... 13 2.3 Upland scrub forest type, CWHvh2/01...... 13 2.4 Bog forest type, CWHvh2/11 ...... 13 2.5 Bog woodland forest type, CWHvh2/12 ...... 13 2.6 Blanket bog, CWHvh2/32 ...... 13 2.7 Edatopic grid depicting forested site series of the CWHvh2 subzone ...... 14 2.8 Open bog development on 2 m of accumulated peat near Prince Rupert ...... 15 2.9 Location of HyP3 intensive study sites and operational trial sites on the north coast of British Columbia ...... 17 3.1 Trough system used to collect rain “throughfall” data at the Diana Lake study site ...... 20 3.2 Stemflow collection system on a redcedar tree at the Smith Island study site . . . . . 21

xiv 3.3 V-notch weir for measuring discharge on a bog stream at the Diana Lake study site ...... 21 3.4 Hydrological response and lag time for small and large rainfall events in the Smith and Diana watersheds ...... 22 3.5 Frequency distribution of rainfall events greater than 1 mm at the Diana Lake study site...... 23 3.6 Percent of total rainfall by event size category at the Diana Lake study site ...... 24 3.7 Interception as a percentage of rainfall, by rainfall event, at the Diana Lake and Smith Island sites...... 26 3.8 Conceptual model of discontinuous soil pipes forming linkages with localized dynamic contributing area...... 29 3.9 Model of groundwater flowpaths in zonal forests and open bogs in the Smith Island watershed ...... 32 3.10 Examples of soil pipes ...... 33 3.11 Comparison of typical storm hydrograph response between the K-pipe and S01 basins ...... 36 3.12 Selected storm recession graphs for the K-pipe and S01 basins during the 2000 field season ...... 37 3.13 Relationship between the S01 basin and K-pipe basin dynamic contributing areas and 10-day antecedent rain ...... 37 3.14 Hydrological parameters measured in a bog at the Diana Lake study site ...... 38 3.15 Dissolved organic carbon concentrations, rainfall, and stream discharge, Smith Island watershed ...... 41 4.1 Historical climatic conditions on the north coast relative to present conditions...... 49 4.2 Canonical correspondence analysis of Diana Lake study plots ...... 58 4.3 Depressions created by mounding at Port Simpson filled in with sphagnum moss after 6 years ...... 60 4.4 Growth patterns of Pleurozium schreberi in relation to climatic parameters for eight consecutive sampling intervals from June 1999 to July 2000 ...... 62 4.5 Growth patterns of four Sphagnum species in relation to climatic parameters for eight consecutive sampling intervals ...... 63 4.6 Change in cover of Sphagnum girgensohnii between 1998 and 1999 at one of the three Port Simpson sites ...... 64 4.7 Four common bedrock types found on the north and central coast of British Columbia ...... 68 4.8 Comparisons of microbial respiration rates and chemical properties...... 72 4.9 Comparisons of microbial respiration rates and moisture content ...... 73 4.10 Changes in C:N and C:P ratios across CWHvh2 site series in old-growth and second-growth stands ...... 73 4.11 Western hemlock nutrient concentrations for current-year needles and 1-year-old needles across height increment ...... 75 4.12 Sitka spruce foliar nutrient concentrations for current-year needles and 1-year-old needles across height increment ...... 76 4.13 Western redcedar foliar nutrient concentrations for current-year needles and older needles across height increment...... 77 4.14 Simplified model of ecosystem development and forest productivity in the CWHvh2 ...... 80

xv 5.1 Zonal forest (CWHvh2/01), Oona River ...... 83 5.2 Bog forest (CWHvh2/11), Diana Lake ...... 83 5.3 Bog woodland (CWHvh2/12), Diana Lake ...... 84 5.4 Open bog (CWHvh2/32), Diana Lake ...... 84 5.5 Productive upland forest (CWHvh2/06), Port Edward ...... 85 5.6 Productive spruce stand on a CWHvh2/08 site, Barnard Creek, Princess Royal Island ...... 85 5.7 Swamp forest (CWHvh2/13), Diana Lake ...... 86 5.8 Dry, windswept rock outcrop (CWHvh2/02), McCauley Island ...... 86 5.9 Second-growth CWHvh2 stand used for site index sampling, Khyex River ...... 87 5.10 Net merchantable volume per hectare by site series and species at the Diana Lake, Oona River, and Smith Island study sites...... 90 5.11 Stems per hectare by site series and species at the Diana Lake, Oona River, and Smith Island study sites ...... 90 5.12 Basal area and stems per hectare in diameter classes at the Diana Lake, Oona River, and Smith Island study sites by site series ...... 91 5.13 Stems per hectare in height classes by site series at all sites and by species at the Diana Lake, Oona River, and Smith Island study sites ...... 92 5.14 Productive yellow-cedar stand on Mount Genevieve, Haida Gwaii/Queen Charlotte Islands ...... 96 5.15 Productive Sitka spruce–western redcedar forest on limestone bedrock, Hamner Island ...... 97 5.16 Kerouard Islands, south of Kunghit Island, Haida Gwaii/Queen Charlotte Islands...... 98 5.17 Tidal estuary, Kwatna Inlet, east of Burke Channel ...... 98 5.18 Sandy beach on the west side of Calvert Island...... 99 5.19 Carex sitchensis fen near Prudhomme Lake, Prince Rupert...... 100 5.20 The predictive ecosystem mapping procedure...... 102 5.21 The EcoGen predictive ecosystem mapping approach ...... 103 6.1 Port Simpson mounding trials...... 106 6.2 Mean height and mean caliper of western redcedar, western hemlock, and shore pine 5 years after planting on mounded and unmounded plots at the Port Simpson study site ...... 107 6.3 Root and shoot biomass of western redcedar, western hemlock, and shore pine 6 years after planting on mounded and unmounded plots at the Port Simpson study site ...... 107 6.4 Rooting characteristics of western redcedar, western hemlock, and shore pine 6 years after planting on mounded and unmounded plots at the Port Simpson study site ...... 107 6.5 Root development of western redcedar growing on unmounded and mounded plots 6 years after planting at the Port Simpson study site ...... 108 6.6 Nitrogen content of pine needles from trees growing on five substrate types at the Port Simpson study site...... 108 6.7 Macronutrient content of pine needles from trees growing on five substrate types at the Port Simpson study site...... 109 6.8 Ecosystem map of Oona River study site ...... 110 6.9 Block 1 at the Oona River study site ...... 111

xvi 6.10 Excavator “hoe-chucking” logs to main skid trail at the Oona River study site ...... 111 6.11  tracked skidder moving logs to the landing at the Oona River study site ...... 112 6.12 Excavator raking and piling slash in block 1 at the Oona River study site ...... 112 6.13 Mixed mineral and organic mound on a CWHvh2/01 site at the Oona River study site ...... 112 6.14 Seedling protectors tested at the Oona River study site ...... 113 6.15 Western redcedar sample tree marked for stem-analysis cutting...... 114 6.16 Aerial view of block 1 at Oona River showing the irregular ecosystem- based boundaries and the individual and patch leave trees ...... 115 6.17 Some redcedar siding and dimensional lumber produced at the Group Mills operation at Oona River...... 117

xvii 1 INTRODUCTION

The HyP3 Project (pronounced “hip • Document the ecology of the blanket cubed”) provides an integrated research bog–upland forest complex of north approach to the study of pattern, process, coastal British Columbia. and productivity in the hypermaritime • Assess the feasibility of managing poor- forests of north coastal British Columbia. and low-productivity cedar–hemlock Initiated in the North Coast Forest forests for timber and fibre production. District in 1997, this project aims to devel- • Define the extent of these sites and op ecologically based guidelines for the identify the potentially operable por- management of cedar-dominated forests, tion. most of which are outside the current • Develop ecologically based manage- operable land base. Lower-productivity ment guidelines for these forests. cedar–hemlock forests that contain This report presents a synthesis of the significant amounts of timber, including HyP3 Project’s 7-year results. It provides high-value western redcedar2 (Thuja plica- an overview of the project to date and ta) and yellow-cedar (Chamaecyparis summarizes initial results for each of the nootkatensis), dominate much of the outer project components—hydrology and bio- coastal landscape; however, considerable geochemistry, ecosystem processes, clas- uncertainty surrounds the feasibility and sification and inventory, and operational sustainability of harvesting these wet, trials. The report concludes with a chapter slow-growing forests. on management interpretations. A glos- HyP3 researchers are using basic sary is also included to define the techni- studies of ecosystem structure and func- cal terms used in the text.3 tion, as well as operational trials, to address the following project goals:

1.1 The Issue The North Coast Timber Supply Area The effects of hand-logging and A- (), within the Coast Forest Region frame operations, which began at the turn (formerly within the Prince Rupert Forest of the 20th century, and the larger indus- Region), encompasses 1.95 million ha trial operations of today, are readily along the British Columbia coast, extend- apparent along the north coast. Harvesting ing from Princess Royal Island to south- was restricted primarily to the highly pro- east Alaska (Figure 1.1). Although 39% ductive steep slopes (often adjacent to (758 788 ha) of the  is considered pro- tidewater) and alluvial valley bottoms ductive forest land, only 6% (119 130 ha) (Figure 1.2). These locations yielded the is currently included within the operable highest volumes per hectare and the great- (timber harvesting) land base because of est return on investment for the relatively limitations associated with environmental costly coastal timber harvesting opera- concerns, accessibility, and timber size tions. Harvesting of some species, such as and quality (British Columbia Ministry of Sitka spruce (Picea sitchensis) and amabilis Forests 1999).4 ﬁr (Abies amabilis), was disproportionately

2 Nomenclature for scientific and common names of vascular and non-vascular plants follows Meidinger et al. (2004). 3 Technical terms included in the glossary appear in boldface at first mention. 4 The boundary of the North Coast  was recently modified and thus the breakdown of the land base provided here has been altered slightly. The area of the  currently totals 1.88 million ha.

1 high compared with their percentage of the standing volume. Very little harvesting has occurred in the lower productivity height class 2 and 3 (< 30 m tall) cedar– hemlock stands typical of the gentler north coast terrain. These stands make up 12% of the  (roughly 235 000 ha), and contain signiﬁcant quantities of both western redcedar and yellow-cedar. These two species often grow together with low-quality western hemlock (Tsuga heterophylla) and mountain hemlock (T. mertensiana), and lesser amounts of shore pine (Pinus contorta var. contorta). Most of these stands are currently exclud- ed from the operable land base because of their low volume (as determined by inventory height class). As the market value of western redcedar and yellow- cedar increases, so does the attractiveness of these stands for harvesting. The current allowable annual cut () for the North Coast Forest District is 573 624 m3.5 This cut is projected to decline in about 20 years (the so-called “falldown” effect) as we shift from cutting old-growth forests to lower-volume second growth. A long-term harvest rate of 361 000 m3 is predicted by the year 2060  . North Coast Timber Supply Area, British Columbia, Canada. (Pedersen 2001). Harvesting in areas that are now considered inoperable may offset reductions in the , or reduce harvesting pressure in the existing operable land base. Before this potential expansion of the operable area can occur, however, concerns about sustainability must be addressed and satisfactorily resolved. In his 2001  determination, the Chief Forester stated, If and when research results indicate the potential to manage some of the exclud- ed stands for timber production from a biological, silvicultural regime and economic viewpoint . . . then it may be appropriate to consider some level of contribution from these stands in a  . Harvested sites on highly productive steep slopes of the CWHvh2 future timber supply review (Pedersen subzone. 2001).

5 The AAC has recently been reduced to 546 624 m3.

2 Thus, before any harvesting occurs, theoretically permit an increase in the  researchers must assess whether these (by up to 120 000 m3), the Chief Forester stands can be managed sustainably (i.e., suggested that any expansion should be in terms of their regenerative capacity used to extend existing harvest levels fur- and site productivity, and the possible ther into the future, therefore maintaining effects on biodiversity and other non- a higher long-term harvest level. timber resources and values). Although In response to the Chief Forester’s ini- expanding the operable land base could tial request for research in his 1995  determination (Pedersen 1995) for the North Coast , Ministry of Forests staff in the (then) Prince Rupert Forest Region commissioned a problem analysis (Kayahara and Klinka 1997). A proposal was then submitted to Forest Renewal BC that outlined plans to carry out research and to develop ecologically based operational guidelines for timber harvesting in the western redcedar–western hemlock forests on the outer coast. Forest Renewal BC approved funding for the project in May 1997. The resulting HyP3 Project has used site-specific studies and operational trials to better understand the area’s ecology, silviculture, and hydrology, and broader classification and inventory studies to identify the potentially operable portion of the land base. In the problem analysis, Kayahara and Klinka (1997) also identified the higher- elevation ecosystems of the Mountain Hemlock (MH) biogeoclimatic zone as another possible area of future operability, but operating in the MH zone was clearly a separate issue requiring its own study. Therefore, the HyP3 initiative was limited to the Coastal Western Hemlock Very Wet, Hypermaritime subzone, Central variant (CWHvh2, Figure 1.3) and did not address issues of sustainable harvesting in the MH zone. Timber inventories usually identify lower-productivity forests on the outer north and central coast as CwYcPl931P,6 921P, or 921L stands, and rate them as  . Distribution of the CWHvh2 within the North Coast Forest District. “inoperable.” The forest sites of interest

6 Codes used on forest inventory maps indicate: species (Cw = western redcedar; Yc = yellow-cedar; Pl = shore pine); age class (9 = greater than 250 years old); height class (2 = 10.5–19.4 m; 3 = 19.5–28.4 m); stocking (1 = mature, greater than 76 stems per hectare); and site class (P = poor; L = low; recently replaced by calculated or estimated site index).

3 matter accumulation over mineral soils (paludification) (Banner et al. 1983; Kayahara and Klinka 1997); therefore, the effect of timber harvesting in promoting or combating this process, and thus influencing second-growth productivity, is of particular interest. Experience in coastal British Columbia, Haida Gwaii/the Queen Charlotte Islands, and southeast Alaska has demonstrated that timber harvesting and associated activities (e.g., road building; Figure 1.4) on steeper slopes increase the likelihood of landslides, which in turn can increase the sediment input into streams (Kayahara and Klinka 1997). Slope stability issues are less of a concern within the lower- productivity stands on gentler terrain; however, access, road building, and forest regeneration in areas of wet, organic soils are significant concerns. Not only does the potential for sediment loading of streams persist, but a host of hydrological changes may effect root zone saturation, nutrient  . Landslide associated with mid- dynamics, and ultimately, forest produc- 1980s road-building activities, tivity. The nature, rate, and extent of coastal British Columbia. such changes have not been documented for this type of environment, so these processes are poorly understood. Finally, for this research occur mainly within expanding the operable land base into the CWHvh2 and typically have wet soils lower-productivity stands could lead to with thick surface organic layers (forest a substantial expansion of harvested floors). Research in north coastal British areas across the landscape and could Columbia and southeast Alaska suggests significantly affect non-timber values, that productive forests can develop such as wildlife, biodiversity, and visual into bogs through a process of organic quality.

1.2 HyP3 Research The HyP3 Project is an integrated, multi- Intensive, site-speciﬁc studies have Approach disciplinary study of the coastal blanket been carried out along two old-growth bog–upland forest complex of the CWHvh2. transects located near Prince Rupert. We are working toward developing a bet- These transects include representative ter understanding of these ecosystems, as examples of the full range of ecosystems well as assessing the feasibility of harvest- studied, from productive forests to blan- ing these areas responsibly and sustainably, ket bogs. Researchers have conducted and providing management guidelines for studies along these common transects to doing so. With this in mind, we used a maximize co-operation among disciplines. combination of scientiﬁc studies, opera- This co-operative approach has helped to tional trials, and inventory techniques to develop a better understanding of how address our four project goals. one ecosystem component, such as

4 hydrology, relates to others such as soil to peat development, and determine ecology or site productivity. how this is linked to site hydrology The more extensive aspects of the study and geochemistry, as well as produc- occur on a range of sites throughout the tivity and ecosystem development. North Coast Forest District. For example, 3. Classification and Inventory operational trials are under way at Oona (Chapter 5) River on Porcher Island, 40 km south of • Describe the range of ecological site Prince Rupert, and near Port Simpson on characteristics associated with the the Tsimpsean Peninsula, north of Prince target forest types, and determine Rupert. Classification and inventory work their operational significance. is ongoing throughout the District. • Examine the use of Predictive The project is organized into the fol- Ecosystem Mapping () to identi- lowing four components, which are fy stands with the highest potential addressed in separate chapters of this for timber management. report. • Identify rare and sensitive compo- 1. Hydrology and Biogeochemistry nents of biodiversity (species and (Chapter 3) ecosystems) that could be at risk • Document the watershed, soil from forest harvesting. hydrology, and biogeochemistry • Estimate growth and productivity of the blanket bog–upland forest across the spectrum of site series in complex. the CWHvh2. • Predict how disturbances from forest • Develop baseline information on the harvesting can affect soil and water- patterns of regeneration and growth shed hydrology, forest succession, in both old-growth and second- and regeneration. growth stands on low-productivity 2. Ecosystem Processes (Chapter 4) sites. • Document relationships among soil 4. Operational Research Trials chemical, biological, and physical (Chapter 6) characteristics, and site series and • Develop and implement a strategy tree productivity. for testing harvesting and silvicultur- • Examine selected biological process- al approaches in target forest types. es, such as soil respiration, litter • Complete the assessment of the Port decomposition, and organic matter Simpson mounding trial, which was dynamics (rates of forest floor and established in 1990. peat accumulation; soil faunal and • Establish additional operational har- microbial activity), in relation to for- vesting trials within the North Coast est productivity and bedrock type.  to better define operability • Examine the potential for manipulat- limits. ing soil characteristics, through Chapter 7 provides management inter- harvesting and site treatments, to pretations for cedar–hemlock ecosystems improve second-growth tree produc- and outlines further research needs. tivity. • Document past and present ecological succession in the area in relation

5 1.3 Previous 1.3.1 Early ecological studies included the development of tree species Studies: Historical Documented ecological studies of the selection guidelines and other manage- Perspective bogs and forests of the west coast of ment interpretations in each of the six British Columbia go back to the early forest regions which existed at that time. 1900s (Rigg 1914, 1917, 1925, 1940; Rigg The coast classification work began in and Thompson 1922; Osvald 1933). These the former Vancouver Forest Region in earliest studies were mostly carried out in southwestern British Columbia (Klinka Washington, Oregon, southwestern et al. 1979, 1980). In 1976, ecosystem clas- British Columbia, and southeast Alaska, sification work began in the coastal por- and concentrated on descriptions of the tions of the Prince Rupert Forest Region, vegetation, peat stratigraphy, and succes- which then encompassed the Mid-Coast, sional relationships of non-forested bog North Coast, and Queen Charlotte Island ecosystems. Williston (2003a) summarized forest districts. Since that time, extensive the history of botanical collecting and ecological sampling has occurred, and research that has occurred on the north reports, theses, maps, and field guides coast since the expeditions of Franz Boas produced which describe the biogeocli- and George Dawson in the late 1800s. matic units and site units—both forests and wetlands—of coastal British Columbia 1.3.2 Ecosystem classification and related (Yole et al. 1982; Banner 1983; Banner studies Beginning in the late 1950s, V.J. et al. 1983, 1986, 1987, 1988, 1989, 1993; Krajina and many of his graduate students Banner and Pojar 1987; Pojar et al. 1988; undertook extensive ecosystem classifi- McLennan and Mamias 1992; Green and cation studies on the west coast. Once Klinka 1994; Klinka et al. 1995; Nuszdorfer again, these were mainly carried out on and Boettger 1994; MacKenzie and Moran the south coastal mainland and Vancouver 2004). During this period, forest compa- Island (Muëller-Dombois 1959, 1965; nies were also carrying out ecosystem clas- Lesko 1961; Orloci 1961, 1964; Wade 1965; sification work within some of the coastal Cordes 1972; Kojima and Krajina 1975; Tree Farm Licences () (e.g., Lewis Klinka 1976). During this time, Krajina 1982; Beese 1983). proposed the biogeoclimatic approach to In 1981, the Royal British Columbia ecological zonation of the entire province, Museum sponsored an expedition to the and produced the first maps of biogeocli- Brooks Peninsula on northern Vancouver matic zones (Krajina 1959, 1965, 1969). Island to document the natural and Spilsbury and Smith (1947), however, car- human history of the area, and to examine ried out forest site classification studies in the evidence for a glacial refugium on the the south coastal area of the province peninsula (Hebda and Haggarty 1997). before Krajina and his students began Vegetation and soil studies on the penin- their work, and first proposed the use of sula highlighted the similarities between site classification to describe site quality this hypermaritime “appendage” on (forest productivity) and ensure “sus- northern Vancouver Island and the blan- tained yield forestry” in British Columbia. ket bog–upland forest complex of the By the mid-1970s, the biogeoclimatic outer coastal lowlands and nearshore ecosystem classification () system islands of the mainland coast to the north had been adopted by the B.C. Ministry of (Hebda et al. 1997; Maxwell 1997). Forests as a framework for forest manage- The HyP3 Project has focused primarily ment. This Ministry’s Research Branch on the most hypermaritime portions of embarked on a province-wide classific- the Coastal Western Hemlock Zone. The ation program and recruited ecologists, unique character of this area—its prep- botanists, soil scientists, and foresters to onderance of blanket bogs and lower- further develop and refine . This productivity “boggy” forests—has sparked

6 controversy about whether it should be the ecosystems described by Neiland included within the CWH zone, or sepa- occur along the north and central coast, rated out as a distinct zone. Much of this though some significant differences are controversy stems from the difficulties evident, such as the lack or scarcity of faced in assessing the relative roles of cli- amabilis fir and western redcedar in mate and landscape factors (e.g., subdued southeast Alaska. Recent descriptions of topography, lack of glacial deposits, domi- the “ecological subsections” of southeast nance of igneous intrusive bedrock geolo- Alaska (Nowacki et al. 2001) also illustrate gy) in controlling ecosystem development that, despite differences in classification and distribution on the outer coast. Pojar concepts and nomenclature, our CWHvh and Annas (1980) proposed that this area subzone in British Columbia extends should be considered a distinct zone, the north into Alaska. Both British Columbian Coastal Cedars–Pine–Hemlock (CCPH) and Alaskan researchers agree that ecosys- Zone, and for several years it maintained tem classification concepts and units must this zonal status within the Ministry of be correlated between the two jurisdic- Forests  system. During the 1980s, a tions (D. D’Amore, U.S. Department of comprehensive correlation of coastal bio- Agriculture, Juneau, Alaska, pers. comm., geoclimatic and site units and reassess- Dec. 2004). ment of plot data helped to determine that the zonal ecosystem within the 1.3.4 Palynological studies With the aim “CCPH” was not sufficiently different of reconstructing past vegetation and cli- from other CWH zonal ecosystems to mate history, the coastal bogs and other differentiate the area as a separate zone. wetlands of the Pacific coast have been Though the controversy continues, the subject of considerable palynological the unique blanket bog–upland forest (i.e., study of the pollen record in peat complex that characterizes the outer coast and sediment profiles) investigation over is currently included as a very wet, hyper- the last 60 years. While many of these maritime subzone of the CWH zone studies have concentrated on describing (CWHvh). broad regional trends in vegetation and climate change since the last glacial retreat 1.3.3 Ecological studies in southeast (Heusser 1960; Mathewes and Heusser Alaska The forest and wetland ecosystems 1981; Hebda 1995), others have emphasized of north coastal British Columbia and more localized interpretation of pollen southeast Alaska are very similar in profiles to reconstruct successional nature. Zach (1950) recognized the appar- sequences in the vicinity of specific sam- ent tension between forest growth and pling sites (Hebda 1977; Banner et al. bog development in southeast Alaska, 1983; Turunen and Turunen 2003). The and was the first to question whether latter approach has helped shed light on “muskeg,” rather than upland forest, rep- the successional relationships between resented the true climax ecosystem. We bogs and forests on the north coast. This have drawn on several other Alaskan stud- palynological evidence, in combination ies to help understand the relationships with studies of soil profiles and natural between vegetation and environment disturbance events such as windthrow along north coastal British Columbia (Ugolini and Mann 1979; Bormann et al. (Lawrence 1958; Stephens et al. 1970; 1995), suggests that paludification, which Neiland 1971). Neiland’s work (1971) is the results from impeded drainage and moss most comprehensive treatment of these encroachment of forested sites on mineral relationships within the “Forest–Bog soils, is an important soil-forming process Complex” of southeast Alaska. Most of on the outer coast, and has significant

7 implications for forest productivity On northern Vancouver Island, a (Banner et al. 1983; Klinger 1990). related management issue dates back to the 1960s when considerable areas of 1.3.5 Forest management research old-growth western redcedar–western Because of the dominance of lower- hemlock forests were harvested and regen- productivity sites on the outer north erated with redcedar, hemlock, and Sitka coast, the question of their potential spruce. Regeneration problems emerged, contribution to the operable land base especially with Sitka spruce. After several has been discussed for many years. In years of acceptable growth, this species 1975, a research project was initiated by began to show severe nutrient deﬁciencies the Prince Rupert Forest Region with the and steadily declining growth rates. These following objective: “… using soil investi- symptoms were not evident in adjacent gations and various studies of plant second-growth western hemlock–amabilis ecosystems, produce a map which will ﬁr stands that originated from a wide- indicate the potential productivity of a site spread 1906 windstorm. Comparison or whether it is possible to improve it for of these two forest types led to several economic gain” (B.C. Ministry of Forests hypotheses about the causes of poorer 1975). Although a small cedar-poling trial growth and nutrition on the cedar– was established in the Lachmach Valley in hemlock sites. The Salal–Cedar–Hemlock 1975, changing staff priorities led to the Integrated Research Program () shelving of this project in 1978; however, was initiated in the early 1980s to test sev- prompted by a high demand for cedar eral of these hypotheses and to establish and perceived future interest in expanding trials looking at the potential for various the operable land base into these lower- mechanical and chemical treatments to productivity cedar-types, this same issue improve second-growth productivity resurfaced 15 years later. In 1990, a project (Prescott and Weetman 1994; Blevins and funded by South Moresby Forest Replace- Prescott 2002). ment Account () was initiated at Some notable differences exist between Port Simpson to look at mounding as a the forest ecosystems on northern site treatment to improve productivity in Vancouver Island and those on the main- cedar-hemlock forest types (Beaudry et al. land coast to the north. 1994). A sister project was also established • Yellow-cedar and mountain hemlock on Haida Gwaii/the Queen Charlotte occurring on the outer north coast Islands that built upon the initial work of commonly extend to sea level, whereas Green (1989) who studied site–forest pro- further south both species are typically ductivity relationships in lowland ecosys- restricted to montane and subalpine tems on eastern Graham Island. forests. In 1997, after the completion of a prob- • Cedar–hemlock forests that dominate lem analysis of the issue (Kayahara and the north coast tend to be lower in pro- Klinka 1997), we decided to expand the ductivity and generally wetter than Port Simpson research into a more inte- those on northern Vancouver Island. grated investigation of the ecological pat- • Salal (Gaultheria shallon) is less domi- terns and processes within the coastal nant and less vigorous on the north blanket bog–upland forest complex. The coast than on northern Vancouver HyP3 Project was initiated with Forest Island, although other ericaceous Renewal BC funding obtained in 1997, and shrubs (mainly Vaccinium spp.) are the Port Simpson study became part of common in the understories of north this larger integrated research project. coast forests.

8 • Glacial deposits (till, outwash), which relatively little experience with second- are typical of northern Vancouver growth management of lower-productivi- Island, are relatively uncommon on the ty forests. north coast, with most soils developing Recent literature shows that forest from weathered bedrock, colluvium, or managers in southeast Alaska are also organic material. concerned about the limits of sustainable Many of the results from  and forest operability. Studies of forest pro- other northern Vancouver Island studies ductivity on transitional “forested wet- (Douglas and Courtin 2001) are undoubt- lands” conclude that these forests meet edly applicable to more northern ecosys- the “minimum standard for commercial tems; however, ecological differences timberland,” but also recognize that man- between the two areas (CWHvm1 and aging these areas for timber production CWHvh1 on northern Vancouver Island presents many ecological and operational vs. CWHvh2 on the outer central and challenges (Duncan 2002; Julin and north coast) are significant enough that D’Amore 2003). Over the past 20 years, directly extrapolating harvesting and joint field trips with colleagues in south- regeneration experience from the south east Alaska have highlighted that British to the north coast would not be appropri- Columbia shares many of the same forest ate. The HyP3 Project has thus built on management issues, and that significant existing information from  by potential exists for co-operation in establishing additional studies on the research efforts. north coast where, to date, we have had

9 2 LOCATION AND ENVIRONMENTAL SETTING

2.1 Location, The geographic scope of the HyP3 Project numerous bedrock types, but dominated Physiography, encompasses the Coastal Western by plutonic and metamorphic groups and Geology Hemlock zone, Very Wet Hypermaritime (Figure 2.1). Plutonic rock, mostly quartz subzone, Central variant (CWHvh2) with- diorite and granodiorite, is the most in the North Coast and North Island – common bedrock type encountered in Central Coast forest districts of the Coast the area. The regions of metamorphic Forest Region. The CWHvh2 includes bedrock are more scattered and are a all coastal islands and a mainland fringe complex mixture of rock types, mostly along the central and north coast of schist and gneiss (Hutchison et al. 1979). British Columbia, from Smith Inlet in the Areas dominated by granitic bedrock south to the Alaska border in the north include Princess Royal Island, Ecstall (Banner et al. 1993) (Figure 1.3). Although River, southern Grenville Channel, and the CWHvh2 also occurs on the western- Fitz Hugh Sound. Areas of metamorphic most Queen Charlotte Ranges and bedrock include Khutzeymateen Inlet, Skidegate Plateau on Haida Gwaii/the Tsimpsean Peninsula, Kaien Island, and Queen Charlotte Islands, our HyP3 studies northern Grenville Channel. Localized did not include these areas. The study area areas of limestone occur on the coast, lies primarily within the traditional terri- mostly in association with metamorphic tory of the Tsimshian on the north coast, bedrock. Highly mixed geology character- but also extends into the territories of the izes Stephens, Porcher, Banks, Pitt, and Nisga’a, Haisla, Heiltsuk, Nuxalk, and Aristazabal islands; Rivers Inlet; and Oweekeno First Nations. Smith Sound (Hutchison et al. 1979; The CWHvh2 occurs in the Hecate Roddick et al. 1979). Lowlands and westernmost Kitimat Although most of the north and central Ranges physiographic regions (Holland coast was glaciated during the last ice age, 1976), and extends from sea level to glacial deposits are rare. This is likely due approximately 600 m elevation. The to a combination of high precipitation Hecate Lowlands form part of the Hecate and steep topography (at least inland of Depression, and encompass a low-lying the Hecate Lowlands) resulting in the ero- strip of subdued and rocky terrain along sion of deposits into the valley bottoms, the outer coast, extending inland to an and then into the sea (Hutchison 1967). elevation of approximately 600 m. The The dominant surface materials are Kitimat Ranges are eroded, predominantly bedrock, saprolite, colluvium, and organ- granitic, mountains that rise to an eleva- ic deposits. Colluvium is more common tion of 2300 m to the east of the Hecate in the steeper Kitimat Ranges, and organic Lowlands, and are part of the Coast deposits are more common on the gently Mountains physiographic region (Holland rolling topography that dominates the 1976). Hecate Lowlands where drainage is poor The geology of the north and central (Valentine et al. 1978). coast is complex and fragmented with

10 2.2 Climate The climate of the outer north and central wetter than those on the offshore islands coast is oceanic, characterized by mild (Environment Canada 1998). temperatures, high rainfall, and low For the most part, precipitation occurs evapotranspiration (Table 2.1). The win- as rain, with little snowfall and many days ters are extremely wet and relatively mild; of fog. With an average of over 220 days sub-zero temperatures may occur for per year of recorded rainfall, prolonged short periods when cold, arctic air covers dry sunny periods are rare (Environment the area. In general, the Paciﬁc Ocean Canada 1998). Soils in this wet environ- moderates temperatures throughout the ment are made even wetter by low evapo- year, and the Coast Mountains serve to transpiration, which results in a very high protect the outer coast from cold winter moisture surplus during the growing and hot summer continental air masses season. This moisture surplus likely has a (Banner and Pojar 1987). The Coast greater inﬂuence on plant growth and dis- Mountains also promote orographic rain- tribution than does total annual precipita- fall, making areas closer to the mountains tion (Banner and Pojar 1987).

 . Generalized bedrock geology, central and north coast of British Columbia.

11  . Climatic data for the CWHvh2 and some adjacent subzones (Banner and Pojar 1987; Reynolds 1997)

Mean Mean Mean Mean Number of Location and Mean annual temperature temperature annual annual days with biogeoclimatic Elevation temperature warmest coldest month precipitation snowfall rainfall subzone (m) (°C) month (°C) (°C) (mm) (cm) > 0.2 mm Prince Rupert, CWHvh2 34 6.7 13.1 –0.2 2523 152 233 Bonilla Island, CWHvh2 16 8.0 13.2 2.8 2104 62 222 Ethelda Bay, CWHvh2 8 7.7 13.7 1.9 3186 144 235 McInnes Island, CWHvh2 25 8.5 14.3 2.9 2558 98 233 Kitimat, CWHvm1 128 6.4 15.9 –4.5 2299 548 195 Ocean Falls, CWHvm1 5 8.1 16.1 0.2 4387 155 218 Stewart, CWHwm 5 5.2 14.5 –5.2 1851 556 164 Alice Arm, CWHws1 314 4.5 14.1 –5.8 2074 841 n/a Kemano Kildala Pass, 1609 –1.4 6.9 –8.5 2793 1816 n/a MHmm1

2.3 Vegetation, The vegetation of the outer north coast is and scrubby, and are dominated by west- Soils, and a complex of productive forests, lower- ern redcedar, yellow-cedar, and western Ecosystems productivity forests, bog forests, bog hemlock; shore pine and mountain hem- woodlands, and blanket bogs (Figures lock occur in variable amounts. Forest 2.2–2.6). The latter three are considered productivity (normally expressed as site wetlands or wetland-like ecosystems and index) on zonal sites is often low com- cover more than 50% of the landscape pared to zonal sites found in other Coastal (Banner et al. 1988, 1993). The disturbance Western Hemlock subzones (Banner et al. regimes characteristic of the outer coast 1993). The shrub layer is usually well have led to a regeneration process domi- developed, and is dominated by salal nated by gap dynamics in these forests. As (Gaultheria shallon), blueberry (Vaccinium a result, most forests are old growth with spp.), and false azalea (Menziesia ferrug- an uneven age structure (Lertzman et al. inea). Common species in the herb layer 1996) dominated by shade-tolerant include bunchberry (Cornus canadensis), conifers, such as western hemlock and deer fern (Blechnum spicant), false lily-of- western redcedar (Banner et al. 1993). the-valley (Maianthemum dilatatum), The major tree species on the outer heart-leaved twayblade (Listera cordata), coast are western redcedar, western hem- and skunk cabbage (Lysichiton ameri- lock, yellow-cedar or cypress, shore pine, canum). The moss layer is dominated by Sitka spruce, amabilis fir, mountain hem- lanky moss (Rhytidiadelphus loreus) and lock, and red alder (Alnus rubra) (Banner step moss (Hylocomium splendens), et al. 1993). Both yellow-cedar and moun- though common green sphagnum tain hemlock are found from sea level (Sphagnum rubiginosum and S. girgen- to subalpine elevations in the CWHvh2 sohnii) and large leafy moss (Rhizomnium (mostly in lower-productivity forests and glabrescens) are often found. Productive bogs at lower elevations), whereas these forests are located mainly on moderate to species are restricted to higher elevations steep, often colluvial, slopes with good in south coastal British Columbia. drainage, and on floodplains; areas of pro- Average or “zonal” sites (i.e., sites that ductive forest are typically interspersed reflect the overriding influence of regional with lower-productivity forests and open climate) in the CWHvh2 are much wetter bogs (Banner et al. 1993). The forested site than zonal sites in any other subzone in series of the CWHvh2 and their position British Columbia. The forests are open on the edatopic grid (Banner et al. 1993)

12  . Bog forest type, CWHvh2/11.

 . Upland productive forest type, CWHvh2/06.  . Bog woodland forest type, CWHvh2/12.

 . Upland scrub forest type, CWHvh2/01.  . Blanket bog, CWHvh2/32.

13 are depicted in Figure 2.7. Detailed nutrient-poor mineral soils compared descriptions of these site series can be with metamorphic rocks (Kranabetter and found in Chapter 5 (section 5.2). Banner 2000; see section 4.5.1). Climate The soils of the forested portion of the is also very important in soil formation, CWHvh2 are imperfectly drained Podzols with high rainfall leading to strongly and Folisols with deep surface organic leached, nutrient-deficient Podzolic min- layers. Wetland organic soils (Fibrisols, eral soils. The extreme amount of mois- Mesisols, and some Humisols) are also ture experienced in the hypermaritime common. Brunisols and Regosols can be environment contributes to the saturated, found on floodplains, and Gleysols are anaerobic soil conditions that promote common on wet sites where mineral hori- moss growth and hinder decomposition zons remain saturated for extended peri- of organic matter; such conditions result ods (Banner et al. 1993). Whatever the soil in thick accumulations of organic forest type, their formation and composition floor materials (Banner et al. 1993). are influenced greatly by the underlying Consequently, on much of the outer coast bedrock geology. Because of a lack of gla- where the terrain is gentle, organic mate- cial till in this area, mineral soils are large- rials have accumulated to form extensive ly formed from decomposed bedrock peatland areas (Figure 2.8). These peat- (saprolite) or from colluvium. Bedrock lands usually contain a scrubby or sparse types vary greatly in their resistance to tree layer in a mosaic of open bogs, bog weathering (Valentine et al. 1978) and thus woodlands, and bog forests. Peat depth in their rate of decomposition and nutri- varies from less than 50 cm on the most ent release. For example, plutonic granitic exposed outer coastal islands to several bedrock is the most resistant to weather- metres in some areas near Prince Rupert. ing and gives rise to relatively thin,

Soil Nutrient Regime very very poor poor medium rich rich A B C D E Relative Actual

very xeric 0 02 Site Series slightly dry 01 Western redcedar – Western hemlock – Salal xeric 1 02 Shore pine – Yellow-cedar – Racomitrium 03 03 Western redcedar – Yellow-cedar – Salal subxeric 2 05 04 Western hemlock – Sitka spruce – Lanky moss fresh Regime 05 Western redcedar – Sitka spruce – Sword fern submesic 3 04 06 Western redcedar – Sitka spruce – Foamflower 06 07 Western redcedar – Sitka spruce – Devil’s club mesic 4 moist 08 Sitka spruce – Lily-of-the-valley (High fluvial bench) 01 09 Sitka spruce – Trisetum (Middle fluvial bench)

Soil Moisture Moisture Soil 07, very moist 10 Red alder – Lily-of-the-valley (Low fluvial bench) subhygric 5 08, 09 11 11 Western redcedar – Yellow-cedar – Goldthread (Bog forest) 12 Shore pine – Yellow-cedar – Sphagnum (Bog woodland) hygric 6 13 Western redcedar – Sitka spruce – Skunk cabbage (Swamp forest) wet 12 10, 13 subhydric 7 Sites of most interest to the HyP3 Project

 . Edatopic grid depicting forested site series of the CWHvh2 subzone (Banner et al. 1993). Circled site series (04, 01, and 11) are of most interest to the HyP3 Project.

14  . Open bog development on 2 m of accumulated peat near Prince Rupert.

2.4 Natural Disturbance histories are distinctly differ- with much poorer drainage, has resulted Disturbance ent within the CWHvh2 between forests in deep accumulations of organic matter Regimes on the steep slopes of the Kitimat Ranges and much lower levels of available nutri- and those on the gently rolling terrain of ents (Kranabetter et al. 2003). In these the Hecate Lowlands. In general, high for- forests, most disturbances are small and est productivity is associated with well- localized, and most gaps are created drained and aerated sites on steep slopes, by stem breakage or blowdown events often with a history of natural disturbance (Lertzman et al. 1996; Nowacki and by landslide or windthrow events over the Kramer 1998; Hennon and McClellan past several hundred years. These distur- 2003). Because of the more subdued ter- bance events tend to mix soil layers, rain, landslides are less common on the slowing the buildup of surface organic outer coast than in the Kitimat Ranges material, exposing mineral soil, and further inland. In addition, large-scale dis- improving nutrient availability (Bormann turbance events, such as major blowdown et al. 1995). More frequent natural distur- or fire, are infrequent throughout the area bances also occur on the floodplains of (Neiland 1971; Nowacki and Kramer 1998). larger rivers (e.g., the Skeena), as well as Return intervals for major disturbances on smaller more confined systems. Fluvial are probably greater than 1000 years for disturbance by flooding can occur annual- most lower-productivity old-growth ly or every few years, depending on bench stands; however, our current estimates of height and weather conditions. disturbance return intervals are specula- In contrast to productive forests on tive, based on limited stand age data. steep slopes and floodplains, the lower- Detailed age structure analysis over exten- productivity cedar-dominated sites found sive areas of old-growth forest on the on the Hecate Lowlands have typically north coast is required to better quantify gone for centuries without major distur- differences in disturbance regimes among bances. This lack of disturbance, together the many forest types.

15 2.5 Adjacent The CWHvh2 is adjacent to several occasionally found in the eastern-most Biogeoclimatic other biogeoclimatic units, including CWHvm2, mostly in areas of cold air Units the Coastal Western Hemlock, Very Wet drainage, while yellow-cedar and moun- Maritime, Submontane and Montane tain hemlock increase in abundance from variants (CWHvm1 and CWHvm2), the the CWHvm1 to vm2 (Banner et al. 1993). CWH Wet Maritime (CWHwm) subzone, The CWHwm is the most northerly and the Mountain Hemlock, Wet Hyper- CWH subzone. It is characterized by steep maritime, Windward variant (MHwh1). rocky terrain, very heavy snowfall, and The CWHvm1 occupies low-elevation lower plant species diversity. Western (submontane) areas inland of the hemlock and Sitka spruce are the domi- CWHvh2. These areas have a wet, humid, nant tree species, with amabilis fir rare mild oceanic climate, but are somewhat or absent, and yellow-cedar and western colder in the winter and warmer in the redcedar infrequent (Banner et al. 1993). summer than the CWHvh2. Amabilis fir is The subalpine MHwh1 is found above more common than in the CWHvh2, and the CWHvh2 on the coastal islands and mountain hemlock and yellow-cedar are adjacent low-lying mainland. The MHwh1 uncommon (Banner et al. 1993). is characterized by heavy snowfalls, a The CWHvm2 occupies higher- short growing season, the dominance of elevation (montane) areas above the yellow-cedar and mountain hemlock, the CWHvm1 (above 350 m elevation). The scarcity of amabilis fir, and the absence of CWHvm2 has a shorter growing season subalpine fir. The distinction between for- and deeper snowpack than the CWHvh2 est and parkland is vague because of the and CWHvm1. Western redcedar and many non-forested wetlands in this sub- shore pine are uncommon in this subzone (Banner et al. 1993). zone. Subalpine fir (Abies lasiocarpa) is

2.6 HyP3 Study Although some aspects of the HyP3 harvesting on soil properties and bio- Sites research and inventory initiatives are diversity. extensive in nature and have been carried out throughout the North Coast Forest 2.6.1 Diana Lake The Diana Lake study District (e.g., Predictive Ecosystem site is located within and adjacent to Mapping), most of the intensive research Diana Lake Provincial Park, 15 km south- activities have been conducted at four east of Prince Rupert. Elevation ranges study sites (Figure 2.9). Studies of ecosys- from 75 to 705 m. The study area contains tem function have been carried out along a typical CWHvh2 cross-section of ecosys- study transects at Diana Lake and Smith tems including zonal lower-productivity Island. These old-growth sites have been forests, bog forests, bog woodlands, blan- used to study hydrology and biogeochem- ket bogs, swamps, and productive forests istry, ecosystem productivity and decom- on steeper slopes. The most common position rates, peatland development and bedrock in the area is gneissic diorite, succession, soil ecology, and old-growth although schist is also present in some forest productivity. Operational trials have locations. Initial studies and installation been established at the Port Simpson and of monitoring equipment began in 1997. Oona River study areas. These operational Ecosystem mapping and permanent plot trials have been used to study harvesting layout were completed, and a meteorolog- methods, silvicultural treatment options, ical station, which records precipitation regeneration issues (natural and artiﬁcial), and wind speed and direction, was log quality and utilization, and effects of installed in an open bog along one of the

16 Dundas Island Port Simpson Operational Trial

Prince Rupert

Study Area Diana Lake Study Area Smith Skeena River Island

Porcher Island Operational Trial Oona River

Pitt Island

 . Location of HyP3 intensive study sites and operational trial sites on the north coast of British Columbia. study transects. Timber cruising and Rupert near the community of Port stream surveys were completed in the Edward. The elevational range of the summer of 2000. Hydrology, geochem- Smith Island site is 0–380 m. The site is istry, and moss productivity studies were dominated by lower-productivity zonal carried out on a continuous basis from forests on gentle slopes, productive forests 1997 until the summer of 2001. Some on steeper slopes, and bog woodlands, destructive tree sampling for growth and bog forests, and open blanket bogs. The yield purposes was also conducted at this bedrock is largely gneissic diorite with site. some schist. Studies were also initiated at this site in 1997 and, in keeping with the 2.6.2 Smith Island The Smith Island methodology established at Diana Lake, study site is located on Smith Island in ecosystem mapping and permanent plot Inverness Passage at the mouth of the layout were completed and a meteorologi- Skeena River, 20 km south of Prince cal station was installed in an open bog.

17 Timber cruising and stream surveys and productive upland forest. The domi- were completed in the summer of 1999. nant bedrock at Oona River is schist. The Hydrology, geochemistry, and moss pro- initial block identification, layout, and ductivity studies were carried out on a ecosystem mapping for this trial began in continuous basis from 1997 until the sum- 1998. The blocks were harvested in June mer of 2001. This site was initially consid- 2000. Late in 2001, plots were established ered for harvest as an operational trial; to test the effects of three site preparation however, visual quality issues, volume treatments: light scarification and raking, concerns, and the high costs associated light scarification and raking with phos- with site accessibility made the harvesting phorus fertilization, and spot raking fol- impractical. lowed by mixing surface organic material with mineral soil to form low mounds. 2.6.3 Port Simpson The Port Simpson All site preparation treatments were com- study site is located 30 km north of Prince pleted using a tracked excavator. After Rupert near the village of Port Simpson treatments were applied, the blocks were on the Tsimpsean Peninsula. The opera- planted with western redcedar and yellow- tional research trial was initiated in 1990 cedar in the spring of 2002 (LePage et al. and incorporated into the HyP3 Project 2002; see Chapter 6, section 6.3). Moni- in 1997. The area is underlain by schist toring of seedling growth and nutrition bedrock and was dominated by lower- began in 2003 and will continue at regular productivity zonal forest before it was intervals. harvested in the late summer of 1990. The intensive HyP3 study areas estab- After harvest, the block was divided into lished to date contain good representation eight plots, four to be mounded and four of CWHvh2 forest and bog ecosystems untreated controls. The objective of the in areas of gneissic diorite and schist trial was to study the effects of creating bedrock. The study areas were chosen, in mounds by mixing the mineral soil with part, because the cedar–hemlock stands the surface organic horizons. The mounds on these bedrock types were considered were created in 1990 using an excavator, (based on earlier ecosystem sampling) to and then planted in 1991 with equal have the greatest potential for forest man- amounts of western hemlock, western agement and, in part, for logistical rea- redcedar, and shore pine. At intervals sons. In addition to the more intensive from 1991 to 1997, measurements of root studies carried out at these locations, vari- and shoot biomass, and height and caliper ous studies involving ecosystem descrip- were taken, and foliar analyses were con- tion, classification, and mapping, soil ducted on the seedlings (Shaw and Banner ecology, regeneration, and site productivi- 2001a, 2001b; see Chapter 6, section 6.2). ty were completed at sites throughout the north coast that encompass the full spec- 2.6.4 Oona River The Oona River opera- trum of bedrock types (see Chapters 4 and tional research trial is located near the 5). To compare findings with the trials on community of Oona River on Porcher metamorphic rock and to expand the Island, 40 km south of Prince Rupert at applications and management interpreta- 0–50 m elevation. The study area compris- tions of the HyP3 Project, plans are cur- es two adjacent cutblocks of 10.2 ha and rently under way to establish additional 7.4 ha. These blocks are primarily com- operational trials in areas of granodiorite posed of three ecosystem types: the lower- bedrock. One such study area at Rainbow productivity zonal forest, which accounts Lake, near Prince Rupert, has been laid for approximately 84% of the harvested out in preparation for harvesting. area, and smaller patches of bog woodland

18 3 HYDROLOGY AND BIOGEOCHEMISTRY

3.1 Introduction Water plays a pivotal role in shaping canopy, thus affecting rainfall interception ecosystem function on the outer coast. and transpiration, and the amount of For this reason, detailed hydrological water reaching the forest floor. Road studies are an important part of the HyP3 building, site disturbance, and site prepa- Project. In hypermaritime ecosystems ration modify soil drainage patterns and such as these, it is critical to comprehend the rate of water runoff. The water-driven the relationships between water and land- biogeochemical processes governing scape processes, as well as hydrological nutrient availability are also influenced by responses to forest management actions. altered site hydrology. An understanding Changes in both forest composition and of how these hydrological changes will soil properties influence hydrological affect long-term forest dynamics and site responses. Forest harvesting and silvicul- productivity is important in the practice tural treatments manipulate the forest of sustainable forest management.

3.2 Watershed Watershed hydrology is the study of water In mountainous areas, precipitation Hydrology movement and storage within a unit of can increase with elevation. As moist air is land that drains all water to a common lifted over a barrier, it cools and the water outlet (Black 1996). Forest management vapour condenses and falls. This is known activities can alter water movement and as orographic precipitation. The relation- storage within a watershed by changing ship between precipitation and topogra- runoff timing and magnitude (Bosch and phy is complex, but is mainly affected by Hewlett 1982). Hydrological effects related the prevailing wind direction, speed, and to forest harvesting and road building humidity. Orographic precipitation can include decreased canopy interception have a significant influence on the water and evaporation, decreased transpiration, balance of watersheds in mountainous changes to snow accumulation and melt, terrain and, therefore, it must be consid- and altered soil hydrology. The watershed ered in water balance calculations. hydrology of an area is frequently described Canopy interception plays an impor- using a “water balance” approach in tant role in determining the amount of which watershed inputs, storage, and rainfall reaching the forest floor. During a outputs are measured. Water inputs are rainfall event, water either penetrates the primarily rain and snow; storage is ground- canopy falling directly to the understorey water within the soil; and outputs are or forest floor, or is intercepted by the evaporation, transpiration, and runoff. canopy. From there it can drip to the The quantification of each of these ele- ground surface, flow down tree stems, ments within undisturbed watersheds is or be held and evaporate. The portion important to gain an understanding of that falls directly to the ground or drips how forest ecosystem disturbances will from the canopy is termed “throughfall.” affect soil moisture, runoff, sedimenta- Rainfall that is intercepted and flows tion, and paludification (bog formation). down the tree trunk is known as “stem- Some initial water balance research in the flow,” and the remainder is called “inter- CWHvh2 was carried out by Beaudry and ception.” Sager (1995); the watershed hydrology The amount of rainfall intercepted by studies of the HyP3 Project were designed a forest canopy depends on storm size, to expand on this work. intensity, duration, weather conditions,

19 forest structure, tree species and architec- measure precipitation and wind direction ture, tree age, tree density, and epiphytic and speed. For orographic effects on rain- growth of mosses and lichens (Crockford fall, measurements were made in openings and Richardson 1990; Beaudry and Sagar at several elevations in both watersheds, 1995; Calder 1998; Spittlehouse 1998). and at the sea-level site at the North Depending on these conditions, the forest Pacific Cannery in Port Edward (reference canopy may intercept 15–35% of annual station). Throughfall was measured using rainfall. ten 5-m troughs at each site (Figure 3.1). Removal of the forest canopy in a wet At Diana Lake, two rectangular “fog environment will introduce more water to harps” strung with vertically oriented already wet soils. Potential effects of this monofilament were used to measure the increased water include larger peak water timing and relative magnitude of fog drip flows, increased erosion, and decreased from January to August 1998. slope and channel stability (Spittlehouse Stemflow was measured on 17 trees at 1998). A higher water table could also Smith Island and 15 trees at Diana Lake result, changing the ecology of the site and using 10-mm collars wrapped 1.5 times leading to regeneration problems, lower around each tree (Figure 3.2). Stream dis- tree productivity, and paludification. charge was measured using a combination of continuous water level recording 3.2.1 Study approach Our methods are devices, stream gauging, and V-notch presented briefly here; if more detail weirs (Figure 3.3). Automatic recording is required, refer to the source papers devices were installed on most installa- (Maloney and Bennett 2002; Maloney et tions. Hemispherical photography was al. 2002; Emili 2003). Meteorological sta- used to determine the canopy closure tions were set up in open bogs at both the above the throughfall troughs (Frazer Smith Island and Diana Lake study sites to et al. 2000). Forest stand characteristics

 . Trough system used to collect rain “throughfall” data at the Diana Lake study site.

20  . Stemﬂow collection  . V-notch weir for measuring discharge on a bog stream at Diana Lake system on a redcedar study site. tree at the Smith Island study site.

were measured using standard prism measured year-round. The change in stor- (variable radius) cruise plots for stems age was assumed to be negligible over over 7.5 cm diameter at breast height time periods as short as a few years, espe- (), with supplemental fixed-area plots cially if the water year selected starts and for stems under 7.5 cm . For the most ends at a time when the soil moisture is part, hydrological installations were main- near its maximum (Dingman 2002). tained for 7–8 months per year (April to Transpiration was the only component October or November) and thus data do that was not measured, and therefore not reflect annual conditions. could be calculated using the above equa- Water balances (or budgets) were tion; however, this calculation also con- determined for watersheds at the Smith tains all measurement errors and is only Island and Diana Lake sites using the considered as a rough estimate of actual equation: transpiration (Maloney and Bennett 2002). Interception was measured in Precipitation = forested ecosystems and thus evaporation stream discharge + evapotranspiration +/– groundwater storage values for the entire study watersheds The precipitation, evaporation (assumed were calculated by multiplying the inter- to equal interception), and discharge ception values by the percentage of the components were measured directly. watershed that was forested (vs. open bog Precipitation at the North Pacific Cannery and other non-forested areas) (Maloney was measured year-round, while precipi- and Bennett 2002). tation at the Smith Island and Diana Lake Canopy interception was determined sites was recorded from April to October using the equation: or November. Stream discharge at the Interception = Smith Island and Diana Lake sites was precipitation – (throughfall + stemflow)

21 Hydrological response (runoff ratio) within 48 hours of the previous rainfall is the ratio of discharge (mm) to rainfall event. input (mm). Lag time closely approxi- mates the time in hours from when one- 3.2.3 Results: orographic rainfall Rainfall half of the rainfall in the event fell to totals at the Smith Island and Diana Lake when one-half of the discharge from the sites were consistently higher than at the event occurs. North Paciﬁc Cannery reference site at Port Edward (Table 3.1). The high-eleva- 3.2.2 Results: hydrological response and tion sites at Diana Lake also recorded timing An analysis of 18 discrete rainfall higher totals than the Smith Island sites. events showed that the hydrological Within the Diana Lake watershed, the response and lag time for both watersheds hillslope site recorded 6.8% more rainfall varied with event size and the weather than the hilltop site, even though the sites conditions that preceded the event. This were at the same elevation. The Diana was particularly noticeable in the hydro- Lake high-elevation sites were 2.3 km logical response to small rainfall events apart on opposite sides of a valley, each following a dry period, which ranged from with topographically different surround- 0.18 to 0.21 (Figure 3.4). If a small event ings. The hillslope site was at a 337 m ele- followed a wet period, the hydrological vation on the leeward side (north aspect) response almost doubled (0.32–0.38). The of a 750-m mountain, while the hilltop hydrological responses for large rainfall site was on top of a 337-m hill. events varied widely regardless of the Although 60% of rainfall events at both moisture conditions that preceded the sites occurred within the 1–19.9 mm cate- rainfall event. The hydrological response gory (Figure 3.5), the greatest amount of for large rainfall events preceded by wet rainfall (26%) occurred within the 20– and dry conditions ranged from 0.26 to 39.9 mm category (Figure 3.6). Approx- 0.81. Although small events after a wet imately 55% of annual rainfall resulted period had a higher response than those from events greater than 40 mm. Rainfall after dry periods, the response was never at both watersheds was closely linked to as great as the maximum recorded from wind direction. Approximately 88% of some large events. In addition, lag time total rainfall at the Diana Lake and Smith was shortest if the rainfall event occurred Island sites occurred with wind from the

Hydrological response 00.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

Dry 7–11 Lag time (hours)

< 50 mm Wet 5–7

Dry Event size 5–10

Wet 4–6 > 50 mm

 . Hydrological response and lag time for small (< 50 mm) and large (> 50 mm) rainfall events in the Smith and Diana watersheds. “Wet” and “dry” refer to whether or not rainfall occurred within the previous 48 hours.

22  . Total monthly rainfall by site and elevation, correlated (r) to the North Paciﬁc Cannery reference site at Port Edward (July–October 1999 and May–October 2000)

Total measured rainfall Difference Site (mm) (%) r Cannery (0 m) 2476 n/a n/a Smith (52 m) 2596 +4.9% 0.99 Smith (332 m) 2747 +11.0% 0.99 Diana Met (72 m) 2834 +14.5% 0.99 Diana south (337 m) 2979 +20.4% 0.99 Diana north (337 m) 3149 +27.2% 0.98

100

90 Cannery Diana 72 m 80 Diana Hilltop 70 Diana Hillslope 60

40 No. of events

0 1– 20– 40– 60– 80– 100– 120– 140– 160– 180– 19.9 39.9 59.9 79.9 99.0 119.9 139.9 159.9 179.9 199.9 Event size (mm)

 . Frequency distribution of rainfall events greater than 1 mm at the Diana Lake study site.

23 30 Cannery Diana 72 m 25 Diana Hilltop Diana Hillslope 20

Total rainfall (%) Total 10

0 1– 20– 40– 60– 80– 100– 120– 140– 160– 180– 19.9 39.9 59.9 79.9 99.9 119.9 139.9 159.9 179.9 199.9 Event size (mm)

 . Percent of total rainfall by event size category at the Diana Lake study site. southeast (121°) to the south-southwest For individual rainfall events, intercep- (210°) (Table 3.2). All large rainfall events tion varied from 10 to 100% (Figure 3.7). also occurred with wind from this quad- The wide range of interception is due to rant. the size, length, and intensity of the rainfall event, and timing relative to other 3.2.4 Results: canopy interception, fog events. Interception decreased with both drip, and stemflow Over the ice-free event intensity and event duration, espe- monitoring periods from May to cially for medium- and long-duration November, 1999–2001, an average of events (Table 3.5). Interception was lowest 1862 mm/yr of rain fell at Smith Island, for events of long duration, regardless of and 1943 mm/yr at Diana Lake (Table 3.3). intensity or canopy state. Interception The average annual interception rate was was greatest, and stemflow and through- 25% at Smith Island and 21% at Diana fall lowest, during low-intensity, short- Lake (Table 3.3). These results are similar duration events, regardless of the canopy to those of Spittlehouse (1998), who saturation level. For these events, inter- observed interception rates of 30% for ception was roughly 62–70% at Smith mature coastal western hemlock forests Island and 69% at Diana Lake. For low- on Vancouver Island, and of Beaudry and intensity, long-duration events, intercep- Sagar (1995), who observed interception tion was roughly 30% at Smith Island and rates of 21% for a coastal redcedar–west- 22% at Diana Lake. The wet or dry condi- ern hemlock forest at Port Simpson, tion of the canopy before the event did 25 km north of Prince Rupert. Monthly not have a major effect on interception. In interception at Smith Island ranged from the dry canopy, throughfall began shortly 12 to 46%, and at Diana Lake from 15 to after the start of a storm event, while a 39% (Table 3.4). Maximum interception delay in stemflow was evident until the was observed during the dry summer canopy was saturated. months, and minimum interception dur- Fog drip was detected on 59% of the ing the wettest months. days during the sampling period

24  . Percentage of rainfall by wind direction

% of total rainfall Diana Lakea Smith Islandb Direction Bearing (°) Cannery 72 m Hillslope Hilltop Cannery 52 m 331 m NE Quadrant 0.1–90 0.3 0.3 0.3 0.3 0 0 0 NNE 0.1–30 0 0 0 0 0 0 0 NE 30.1–60 0 0 0 0 0 0 0 ENE 60.1–90 0.3 0.3 0.3 0.3 0 0 0 SE Quadrant 90.1–180 59.8 61.1 59.5 60.5 79.8 79.5 79.0 ESE 90.1–120 1.1 1.4 1.4 1.4 6.9 7.0 6.9 SE 120.1–150 25.4 25.0 26.4 25.2 23.5 22.9 23.0 SSE 150.1–180 33.2 34.7 31.8 33.9 49.5 49.6 49.1 SW Quadrant 180.1–270 39.8 38.3 39.7 38.9 20.0 20.2 20.4 SSW 180.1–210 29.6 28.9 30.2 29.1 14.4 14.8 14.8 SW 210.1–240 8.1 7.6 7.4 7.7 3.6 3.3 3.3 WSW 240.1–270 2.1 1.8 2.1 2.1 2.0 2.1 2.3 NW Quadrant 270.1–360 0.1 0.3 0.4 0.3 0.2 0.4 0.5 WNW 270.1–300 0.1 0.3 0.4 0.3 0.2 0.4 0.5 NW 300.1–330 0 0 0 0 0 0 0 NNW 330.1–360 0 0 0 0 0 0 0 Total rainfall (mm) 2475 2833 3149 2979 2475 2595 2745 a Cannery results calculated using Diana Lake anemometer. b Cannery results calculated using Smith Island anemometer.

 . Annual rainfall, throughfall, stemﬂow, and interception at the Smith Island and Diana Lake sites (May–November, 1999–2001)

Smith Island Diana Lake Total Canopy Total Canopy rainfall throughfall Stemflow Interception rainfall throughfall Stemflow Interception (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm) 1999 2133 1443 22.9 667 2156 1673 17.6 465 2000a 1793 1345 21.0 427 1800 1429 15.5 356 2001a 1659 1308 22.1 329 1873 1446 15.6 412 Average 1862 1366 22.0 474 1943 1516 16.2 411 % 73.4 1.2 25.5 78.0 0.8 21.2 a To account for canopy variability, the location of throughfall troughs changed to five new locations for 2000 and 2001.

 . Maximum and minimum monthly interception as a percentage of rainfall at the Smith Island and Diana Lake sites (May–November, 1999–2001)

Smith Island Diana Lake Total Total rainfall Interception Interception rainfall Interception Interception (mm) (mm) (%) (mm) (mm) (%) Maximum 515.5 62.3 12.1 607.5 91.7 15.1 Minimum 60.5 27.9 46.1 73.5 28.9 39.3

25 120 Diana Lake

100

60 Interception % Interception 40

0 0 50 100 150 200 Rainfall (mm)

120 Smith Island

100

Interception (%) Interception 40

0 0 50 100 150 200 Rainfall (mm)

 . Interception as a percentage of rainfall, by rainfall event, at the Diana Lake and Smith Island sites. Calculations assumed a constant stemﬂow of 1.2% at Smith Island and 0.8% at Diana Lake.

26  . Rainfall interception sorted by canopy condition, event intensity, and event length

Smith Island Diana Lake Canopy Intensity Event length Interception Interception condition (mm/hr) (hrs) n average (%) n average (%) Wet (< 24 hrs Low < 5 117 62 78 69 without rain) (≤ 1 mm/hr) 5–24 109 41 104 30 >24 29 30 19 22 High < 5 6 37 4 28 (> 1 mm/hr) 5–24 38 24 26 17 >24 31 19 32 18 Dry (> 24 hrs Low < 5 45 70 20 69 without rain) (≤ 1 mm/hr) 5–24 21 41 24 28 > 24 4 30 6 21 High < 5 0 – 2 43 (> 1 mm/hr) 5–24 14 28 11 24 > 24 9 23 11 19

(January–August 1998) and 99% of this larger trees have a greater interception occurred during rainfall events. However, area and also extend above the main with the type of collectors used in this canopy. The absence of foliage on dead study, it was difficult to differentiate the trees means that there is less surface area contributions of fog, drizzle, and rain. to intercept rainfall, and thus less Compared with studies of fog drip in stemflow. The results from the smaller other coastal forests (Azevedo and tree classes were mixed, making interpre- Morgan 1974; Harr 1982), the amount of tation difficult. fog drip, as indicated by throughfall in Stemflow represents a small compo- the absence of rainfall, was lower than nent of forest hydrology, but it plays an expected in these north coast forests. important role in directing water to tree Nevertheless, cloudwater or fog drip roots, and while the added water may not inputs may be more substantial at higher be important in hypermaritime areas, elevations or at more exposed locations stemflow is often enriched with nutrients on the north coast; fog could thus be a from tree canopies and trunks. So significant source of nutrient inputs to although stemflow represents a small per- some sites (Bormann et al. 1989). centage of total water input, it has been Stand stemflow as a percentage of total shown to have a larger effect on the qual- rainfall averaged 1.2% at Smith Island and ity of water entering the soil (Johnson 0.8% at Diana Lake (Table 3.3). At Smith 1990). Island, monthly stemflow ranged from 1.1 to 1.3% of total rainfall, while at Diana 3.2.5 Results: water balance Water bal- Lake, stemflow measured 0.8% of total ances were performed for the Smith Island rainfall. The differences in monthly and Diana Lake watersheds between stemflow are likely due to a number of September 1, 1998, and August 31, 2001. factors, including canopy state (dry or Each water balance was performed for a wet), and rainfall intensity and angle water year (September to August). Results (Crockford and Richardson 2000). are summarized in Table 3.7. A separate In general, large trees produced a water balance was performed for an addi- greater amount of stemflow than their tional small watershed in the Diana Lake proportion of the stand at both sites, with study area; however, because of the nega- dead trees producing less (Table 3.6). The tive residual values for this watershed, the

27  . Production of stemﬂow by tree size class

Smith Island Diana Lake Sample Sample trees in % of % of trees in % of % of Tree Class class trees stemﬂow class trees stemﬂow  < 7.5 cm 3 50 52 4 42 35  7.5–17.5 cm 2 13 1 3 26 33  > 17.5 cm 8 13 30 5 9 20 Dead trees 4 24 17 3 23 12

 . Water balance for the Smith Island and Diana Lake watersheds, 1998–2001

Groundwater Channel Precipitation Evaporation storage change discharge Location (mm) (mm) % (mm) % depth (mm) % Residuala % Smith Island 1998–1999 3613 797 22.1 0 0 2433 67.3 383 10.6 1999–2000 3930 805 20.5 0 0 2448 62.3 677 17.2 2000–2001 3650 664 18.2 0 0 2634 72.2 352 9.6 Average 3731 722 19.4 0 0 2505 67.1 504 13.5 Diana Lake 1998–1999 4110 586 14.3 0 0 3110 75.7 414 10.0 1999–2000 4523 659 14.6 0 0 3604 79.7 260 5.7 2000–2001 4158 602 14.5 0 0 3210 77.2 346 8.3 Average 4264 616 14.4 0 0 3308 77.6 340 8.0 a Residual value includes transpiration and measurement error.

results were deemed less reliable and including error estimates of ± 5% for are not presented here. For a complete stream discharge values and ± 10–15% for description of the HyP3 water balance interception values. Winter interception studies, see Maloney and Bennett (2002). was an additional uncertainty in this The Diana Lake study site had a greater study. October interception values were orographic effect and, therefore, average used to estimate winter interception; how- precipitation values were higher there ever, winter interception will depend on (4264 mm) than at Smith Island (3731 highly variable weather conditions, espe- mm). Stream discharge accounted for 78% cially the percentage of precipitation of annual precipitation at Diana Lake and falling as snow (Schmidt and Troendle 67% at Smith Island. Evaporation (calcu- 1992; Pomeroy and Schmidt 1993; Woo et lated using forest interception data and al. 2000). The estimated transpiration for forest cover information for each water- the HyP3 study watersheds is thus expect- shed) accounted for 14% (Diana) to 19% ed to contain a considerable element of (Smith) of precipitation. This left average error. residual values of 8% at Diana Lake and Beaudry and Sagar (1995) completed a 14% at Smith Island, a portion of which water balance for a coastal cedar–hemlock would be transpiration with the remain- ecosystem north of Prince Rupert using a der accounted for by measurement error. combination of climate and interception Maloney and Bennett (2002) outlined var- measurements and climate modelling. ious sources of error in hydrology studies, Their study lacked streamﬂow data, but

28 derived evapotranspiration values through precipitation, respectively. These stream- modelling; in contrast, the HyP3 studies flow and evaporation estimates, as well as had extensive streamflow data, but lacked total precipitation (3673 mm), are compa- detailed estimates of transpiration. For the rable with the HyP3 study sites, especially water balance, Beaudry and Sagar calcul- the Smith Island site; therefore, a transpi- ated streamflow to represent 75% of total ration estimate of ± 4% may be reason- precipitation, with evaporation and tran- able for these hypermaritime watersheds. spiration representing 21% and 4% of

3.3 Soil How water behaves in the soil has a large well-decomposed organic material Hydrology and influence on the way a site reacts to har- (National Wetlands Working Group Biogeochemistry vesting-induced changes in hydrology. 1997). The surface layer is the most hydro- Soil composition (i.e., whether the soils logically active, with flow rates that may be are dominated by mineral or organic several orders of magnitude greater than materials) is an important factor in in the lower layer (Ingram 1983). Conse- the soil response on the north coast. quently, when the water table is near or at Ecosystems with soils dominated by the surface of the bog, the water is free to organic materials include some zonal move through the more active surface scrub forests, as well as bog forests, bog layer (Waddington and Roulet 1997). woodlands, and open peatlands. In addi- Soil pipes are a type of macropore tion to soil composition, hydrological that run nearly parallel to the soil surface linkages between forests and wetlands (Figure 3.8) and are commonly found can also affect hydrological responses. in many soil types (Uchida et al. 2001). Typically, peat-dominated sites (e.g., Water flow through pipes is called bogs) have two main soil layers. The 10– pipeflow. Pipeflow can be a critical hydro- 50 cm upper layer contains plant materials, logical process that allows the rapid trans- both live and poorly decomposed, includ- fer of water to stream channels. Soil pipes ing roots and the remains of vascular and are thus important in determining effec- non-vascular vegetation. The lower layer tive hydraulic conductivity. Pipes can is primarily perpetually saturated, be disturbed by harvesting activities,

 . Conceptual model of discontinuous soil pipes forming linkages with localized dynamic contributing area.

29 potentially changing the drainage patterns probes were used to measure soil moisture of the harvested area. content. Automatic recording data-loggers Soil biogeochemistry, and changes to were included at many of these instal- its dynamics, can also have significant lations. effects on forest management and other Hydraulic conductivity was determined resource values. For example, plant pro- using bail tests, and hydraulic gradients ductivity is closely tied to nutrient avail- were calculated using a combination of ability, which in turn can be affected by levelling across the study area and relative water table height and soil aeration. Both water table measurements. Water samples water table height and aeration can be were either collected by hand or with altered by forest harvesting practices. automatic collecting devices; chemical Carbon cycling is another biogeochem- analyses were done in the laboratory. ical process that can be affected by har- Natural and artificial tracers were com- vesting. Carbon cycling in the highly monly used to determine groundwater organic soils of the north coast involves flow rates and pathways, and water contri- the movement of large amounts of dis- butions from different sources (e.g., vege- solved organic carbon () within tation types and soil layers). The tracers the soil profile (Vance and David 1991). used included , ratios of the isotopes Dissolved organic carbon increases water of oxygen (18O/16O) and hydrogen acidity and darkens the water, which gives (2H/1H), salt water, and dyes. In some rise to the naturally tea-coloured water of cases, hydrograph separation techniques the area. The dark water, in turn, lowers were then used to determine the quantity light penetration, while the increased of water contributed to streams by differ- acidity influences nutrient availability and ent sources before, during, and after rain- increases the ability of the water to trans- fall events. Hydrological responses to port metals (Davies-Colley and Vant 1987; rainfall events were ascertained using a Driscoll et al. 1989; Driscoll et al. 1995). combination of rainfall data, water table High  levels in streamwater also have heights, stream discharge volumes and important implications (both positive and curves, the chemical composition of negative) to aquatic biological processes. water, and hydrograph separations.

3.3.1 Study approach Soil hydrology was 3.3.2 Results: water tables Depth to studied at both the Diana Lake and Smith the water table was much greater in the Island research sites. Numerous methods upland forest than in the other vegetation were used to determine the hydrological types (Table 3.8). The shallowest water dynamics of the sites. Our methods are table depth occurred in the swamp forest presented here briefly; if more detail is where the water table was often above the required, refer to the source documents ground surface. In most cases, differences (Gibson et al. 2000; Lortie 2002; Fitzgerald in water table depths are closely related to et al. 2003; Emili 2003). forest productivity. In general, the sites Meteorological stations were placed in with low water tables are more productive open bogs at both study sites to measure for trees than those where the water table precipitation. V-notch weirs were set up is near the surface, saturating the rooting in several locations in the watersheds to zone. The swamp forest, however, is an track discharge. Wells and piezometers exception—the surface topography allows were installed in specific vegetation types trees to establish on elevated and better- throughout the study areas to determine aerated microsites, and to absorb (some of water table depth and hydraulic head. the) nutrients in the relatively rich miner- Time domain reflectrometry () al seepage of the saturated depressions

30  . Average depth to water table, pH, and dissolved organic carbon (DOC) of groundwater from mineral and organic soil horizons by site series (adapted from Emili, 2003)

pH DOC (mg/L) Water table depth Organic Mineral Organic Mineral Site series (cm) (SD)a horizon horizon horizon horizon Upland forest (04) 93.0 (7.1) n/a 6.03 n/a 8.2 Scrub forest (01) 22.2 (7.6) 5.04 5.52 17.6 11.1 Bog forest (11) 14.3 (6.5) n/a 5.19 12.6b 7.5b Bog woodland (12) 15.3 (5.0) 4.89 5.44 Open peatland (32) 7.9 (6.9) 4.85 5.62 16.6 10.2 Swamp forest (13) 3.2 (5.4) n/a n/a n/a n/a a Standard deviation. b DOC data combined for the bog forest and woodland vegetation types.

(Banner et al. 1993). The physical amount water retention capacity, which enables of water table fluctuation, as indicated by them to retain pore water for long per- the standard deviation, was similar at all iods, and thus remain saturated. Wet soil sites. At sites with high water tables, how- conditions facilitate the accumulation of ever, the water table is often very close to organic matter, restrict tree growth, and the surface where the saturated conditions favour the establishment of wetland affect tree growth. species, such as sphagnum mosses and sedges. 3.3.3 Results: soil hydrological dynamics The low hydraulic conductivity of the The hydrological dynamics of the outer organic soil matrix encourages alternative north coast depend on several interacting subsurface pathways (e.g., pipes and factors. Ground surface slope, as shown macropores) to develop, which are critical by a slope index (that combines slope in removing water from these sites. Often angle and slope length), influences short (5–10 m) and terminating in seeps drainage rate and, therefore, water table and rills, these pathways permit more height and soil moisture content (Emili rapid water movement than the regular 2003). Lower slopes and depressions are soil matrix flow (Gibson et al. 2000). The wetter and tend to accumulate organic low hydraulic conductivity of organic soils matter in the form of peaty soils. This also results in surface flow during storm relationship is quantified by the slope events. index that, in turn, is related to vegetation Hydraulic conductivity is also an type and organic soil depth (Emili 2003). important factor in the variation of water These findings correspond with those of residence times in organic and mineral Asada (2002), who found that vegetation soil-based terrain types. In organic soils, types were most influenced by water table low hydraulic conductivity results in soil depth and slope. water retention and, therefore, little Peaty soils, in a positive feedback loop, unused storage capacity is available to profoundly influence soil drainage charac- absorb water from the next rainfall event. teristics. These organic soils have a low This forces new water to leave organic hydraulic conductivity, which decreases soils quickly. As a result, streams in water infiltration rates and groundwater organic soil terrain types are less stable flow, and restricts soil water discharge (i.e, “flashier”) than those in mineral soil (Emili 2003). The soils also have a high terrain types (Gibson et al. 2000). In

31 addition, runoff patterns are influenced by receives a small proportion of the new the weather conditions preceding a storm water inputs, especially in the bogs, event. because of the low hydraulic conductivity Hydrological dynamics differ with rain- of deeper organic horizons, and the rela- fall intensity and between the soil surface tively few macropores in the deeper soil and subsurface layers. These differences horizons (Gibson et al. 2000; Lortie 2002). are attributed, in part, to the presence of At low rainfall intensities, a “first-in- peat, which maintains a shallow water first-out” hydrological dynamic generally table (Gibson et al. 2000). In the scrub exists, where old water is pushed out of forest, the shallow groundwater system the system using internal soil flow path- responds rapidly to rainfall events, as indi- ways. At high rainfall intensities, the flow cated by a rapid rise in water table and capacities of these pathways are exceeded  concentrations in the shallow and alternative pathways involving rapid groundwater and streams during rainfall flow (i.e., rill and seep flow) are invoked. events, but not in the deep groundwater. This results in a “last-in-first-out” hydro- A shallow water table keeps most of logical dynamic, where streamflow is the inputs of water in the near-surface dominated by new water (Gibson et al. groundwater zone, and much exchange 2000) that usually travels through shallow occurs with the surface as groundwater groundwater pathways before reaching the seeps. Incoming water moves through stream (Figure 3.9). After rainfall events, the upper soil layers, exits the soil from deep groundwater resumes its role as the numerous groundwater seeps, and flows major contributor to streamflow. The over the ground surface before reaching rainfall threshold at which the flow-pattern the stream. Conversely, the deep ground- change occurs is not known, but is likely water system shows little reaction to rain- lower after harvesting because of the fall events (Gibson et al. 2000; Lortie decreased rainfall interception by the 2002). The deep groundwater zone only canopy.

 . Model of groundwater flowpaths in zonal forests and open bogs in the Smith Island watershed. Dashed line is the water level beneath the ground surface and in the stream. Solid lines represent the groundwater flowpaths: SH = shallow hillslope flowpaths; DH = deep hillslope flowpaths; SB = shallow bog flowpaths; DB = deep bog flowpaths; S = groundwater seep.

32 3.3.4 Results: pipeflow studies In north Excavation revealed that channelled coast lowland forests, four main factors sections of pipes were continuous over appear to facilitate the development of short distances (5–10 m). Water tracing soil pipes: with salt water and dye, however, showed 1. presence of a soil discontinuity with that hydraulically effective and connected depth (i.e., a highly conductive surface flow paths occurred over much longer dis- organic layer [1–55 m/day] overlies a tances, likely through linkages at nodes. low-conductivity [0.0004–0.002 m/day] These nodes can be tree root masses, areas peat); with more highly hydraulically conductive 2. steep hydraulic gradients; soil, deadfalls, or zones where overland 3. organic soils with low cohesion; and flow occurs. 4. high volume of living roots and buried During a storm, the size of an area con- coarse organic material. tributing to direct runoff expands and In this setting, pipes may form by contracts according to a theory known as a subsurface flow through the surface the “variable source area concept” (Dunne organic layer, which cuts into the underly- and Black 1970). This area is calculated ing, more decomposed organic soil. With using the following formula (Jones 1997): little solid soil structure to hold it in place, Total storm discharge this organic soil is often eroded, allowing in pipe or stream (m3) pipe formation. Pipes were found through- Area = Total storm rainfall (m) out soil profiles at the study sites, but were most abundant at structural voids and This formula uses the amount of water roots (i.e., at the junction between high- discharged during an event and the and lower-conductivity soil horizons), amount of rainfall that fell during an at the soil–root interface (Figure 3.10a), event to determine the area that con- along conduits of decayed roots, and tributed to discharge. along the soil–bedrock interface (Figure The area that contributes water to a 3.10b). pipe during storms may be enlarged by a

a b

 . Examples of soil pipes: (a) excavated soil pipes formed around live roots located in a cedar–hemlock forest; (b) soil pipeﬂow directed into a bucket weir for measurement of discharge.

33 rising water table, overland flow from at Inverness Passage (Figure 3.10b). Live perched saturated zones, or groundwater and dead tree root masses and areas of which discharges at the surface and flows ponded water occurred at irregular inter- into pipe channels. This drainage system vals along this pipe. Beyond 7 m, surface is similar to the discontinuous macro- evidence of the pipe vanished into a pores on forested hillslopes in Japan thick (> 1.5 m) deposit of peat. Along described by Sidle et al. (2001), although a 100 m section of the wave-cut terrace, the north coast of British Columbia has eight smaller soil pipes were noted. With a much wetter hydrological regime. the exception of one other perennial pipe, Two basins were chosen for monitor- all of these flowed ephemerally. ing, each with different physical character- Though similar CWHvh2/01 forests istics (Table 3.9). These basins were dominate both basins, notable differences chosen for their small size, which facili- are apparent in soil characteristics and tated the integration of climate–soil– topography (Table 3.9). Soil depth at the vegetation dynamics, their proximity to S01 basin averaged 0.6 m on hillslopes, pre-existing monitoring areas, and their greater than 1.5 m in mid-slope boggy contrasting drainage systems. The larger benches, and greater than 3 m in the bog of the two basins, the “S01 basin,” is dom- forest. Soil depth at the K-pipe basin was inated by a small first-order stream, which seldom greater than 1.2 m, with hydraulic originates near the toe of a scrub forest conductivity averaging three orders of slope at the margin of a bog containing an magnitude greater than the S01 basin. abundance of buried deadfall. The stream Here, the zone of highest conductivity meanders for about 30 m before discharg- roughly coincided with the suspected ing into “Smith small stream.” Runoff depth of the pipe channel. from the second basin, the “K-pipe basin,” Surface water storage exerts a greater is dominated by a 10–20 cm diameter soil influence over the K-pipe basin than the pipe that is 30–50 cm below the surface at S01 basin; swampy areas of standing water the organic–mineral and mineral–bedrock cover approximately 20% of the K-pipe interfaces. The K-pipe basin was traced basin. During storms, these areas expand visually over 7 m from its discharge point to form a network of pools linked by areas through a wave-cut terrace on the beach of return flow. Presumably, this is the

 . Characteristics of the S01 and K-pipe basins

S01 basin K-pipe basin Basin area (m2) 7331 2763 Drainage ﬁrst-order stream Perennial soil pipe Slope 8–38° 5–10° Soil thickness (m) 0.1 to > 3 0.5–1.5 Hydraulic conductivity (m/d) 0.00038–0.13 2–51 average = .024 average = 25 Dominant vegetation Approx. 50% moderately sloping Gently sloping scrub forest: western scrub forest: western redcedar, redcedar, yellow-cedar and hemlock, yellow-cedar and hemlock; and with interspersed swamp forest and approx. 50% gently sloping bog abundant surface pools. forest, scattered areas with standing water. Dominant site series 70% 01 scrub forest 70% 01 scrub forest 30% 11 bog forest 30% 13 swamp forest

34 surface expression of pipe channel flow through surface macropores and higher- under pressure, as the pipe channel varies conductivity soils. its course both vertically and horizontally The dynamic contributing areas () within the soil profile (Woo and Dicenzo for the S01 and K-pipe basins were com- 1988). In contrast, the S01 basin has much pared with measures of basin wetness to smaller isolated pools of standing water determine the controls on runoff (Figure that are restricted to riparian zones at the 3.13). The S01 basin’s  is generally well base of the CWHvh2/01 hillslope and at predicted by the following measures of scattered sites throughout the bog forest. basin wetness: The typical stormflow and ground- • antecedent water level (r 2 = 0.70–0.95); water response (Figure 3.11) to a well- • 1-day antecedent soil moisture defined, single-peak storm event was rapid (r 2 = 0.48–0.75); and from both the K-pipe and S01 basins, with • 5- and 10-day antecedent precipitation similar peak rainfall to peak discharge (r 2 = 0.63–0.75). times for each. The response time (meas- The K-pipe basin s had somewhat ured as the difference between the start of different relationships with measures of rainfall and initial increase in discharge) basin wetness. The s grew with for the K-pipe basin, however, was about increasing antecedent precipitation to twice as rapid (average of 2 hours). Even about 20 mm. Between 20 and 50 mm 10- when the antecedent groundwater level in day antecedent precipitation, contributing both basins was similar, the threshold areas began to shrink. Contributing area groundwater level required to initiate had an inverse relationship with the fol- stormflow differed. In the S01 basin, an lowing precipitation indices: magnitude, increase in stream discharge coincided intensity, rainfall depth before peak flow, with a water table rise to within 5–10 cm and storm duration. The apparent shrink- of the surface. In the K-pipe basin, pipe ing of s as the catchment becomes discharge started to appreciably increase wetter is explained by the activation of when the water table rose above the base ephemeral soil pipes under very wet con- of the pipe channel, which was about ditions. With increasing catchment wet- 30 cm below the ground surface. Baseflow ness, these pipes serve to divert stormflow separation revealed consistently higher away from the K-pipe basin, which results contributions of baseflow to the K-pipe in a smaller apparent contributing area. basin (16–44%) compared with the S01 This was corroborated by the pipeflow basin (10–34%). tracer experiments, which established The S01 basin receded much faster connections between the K-pipe basin and than the K-pipe after storms, exhibiting a number of neighbouring ephemeral progressively steeper recessions with pipes. decreasing discharge (Figure 3.12a and Compared with the S01 basin, the 3.12b). The abrupt recession observed in K-pipe basin experienced a more rapid the S01 basin is explained by smaller con- response to precipitation and more grad- tributions from baseflow, rapid discon- ual recessions because of its intimate nection from the bog forest and hillslope contact with the water table, higher- source areas, the lack of dynamic storage conductivity soils, and affiliation with a in the stream channel, and seepage losses network of smaller ephemeral pipes and to the gravel streambed and surrounding nodes. Another factor involved in the soil. Conversely, the extended recessions rapid response of the K-pipe basin, and observed in the K-pipe basin imply a expansion of the contributing area during more intimate contact with the water a storm, is its large area of swamp forest table, and greater post-peak contribution with significant surface depression storage. from swampy surface depressions draining Swamp forests can have a large proportion

35 0 (a)

Precipitation (mm/h) 4

1 (b) 0 Recording wells SO1 basin –1 (distance from weir)

–2 Midslope 01 well (45 m) –3 –4 Water table (cm) Water –5 Bog–forest well (28 m) –6 Riparian 01 well (39 m) –7

0.85 ) (c) TDR response (~3 m from SO1 stream) 3 /cm 3 0.80

0.75 Soil moisture (cm 0.70

1.5 (d) K-pipe SO1 stream

1.0

0.5 Discharge (L/sec)

0 148 149 150 151 152 Day of year (May 27–30, 2000)

 . Comparison of typical storm hydrograph response between the K-pipe and S01 basins: (a) precipitation during event; (b) water table depth at three locations; (c) soil moisture response in S01 basin; (d) discharge proﬁle from the K-pipe and S01 basins.

36 1.6 May 30 1.4 (a) (b) May 30 1.2 June 15 June 15 1.0 June 19 June 19 0.8 June 25 June 25 August 11 August 11 0.6 August 18 1 August 18 August 20 August 20 0.4 August 22 August 22 August 27 August 27

0.2 Discharge (log10 L/sec) Discharge (log10

Discharge (log 10 L/sec) Discharge (log 10 0.1

0 0.5 1.0 1.5 2.0 0 0.5 1.0 1.5 2.0 Time (days) Time (days)

 . Selected storm recession graphs for the (a) K-pipe and (b) S01 basins during the 2000 ﬁeld season.

3 K-pipe basin the ground surface. Consequently, the S01 S01 basin basin becomes rapidly disconnected from source areas as the water table declines. Because the S01 basin has much steeper 2

) slopes and contains only a minimal area 3 of swamp forest, overland flow and preferential flow are common, but largely restricted to discrete areas of the basin. DCA (000 m 1 3.3.5 Results: hydrological landscape linkages The mosaic of vegetation types typical of the north coast suggests that 0 hydrological linkages between site series 0 1020304040607080 are common; therefore, forest manage- 10-day antecedent rain (mm) ment actions may have hydrological effects that extend beyond the boundary  . Relationship between the S01 basin of the harvested forest type. Some forest and K-pipe basin dynamic types may have a larger controlling contributing areas (DCA) and 10- influence on watershed hydrological day antecedent rain. dynamics than others. This section summarizes the results of an investigation of of a basin’s water routed through them, hydrological linkages among several site causing discharge to increase rapidly when series within the Diana Lake study area. storage capacity is exceeded (Fitzgerald et al. 2003). In the S01 basin, streamflow is Bog isolation By definition, bogs are fed primarily by shallow subsurface flow peatlands that receive water input exclu- through the near surface peat and by sively from direct precipitation (National overland flow as the water table intersects Wetlands Working Group 1997).

37 Consequently, bogs are usually considered 20 hours, and during the second event, 56 to have no groundwater and surface water mm fell in 47 hours (Figure 3.14a). Using inputs from the surrounding landscape. the water budget equation (see section Some evidence, however, suggests that this 3.2.1), we calculated that 121 m3 of rain fell isolation is less absolute than previously on the bog during the first event. Of this thought (Siegel et al. 1995). Establishing amount, 106 m3 was taken up in ground- this hydrological autonomy is essential to water storage and 13 m3 was discharged understand the implications of disturb- over the stream weir, which accounted for ances in the forests adjacent to wetland 119 m3 of the 121 m3 input (Figures 3.14b ecosystems. For example, if bogs are and 3.14c). Evapotranspiration over the hydrologically isolated, and no harvesting- duration of the storm event was likely related activities occur directly on the bog negligible and, therefore, ignored. For the surface, then activities on slopes above or second event, we calculated that 400 m3 of below the bog may not greatly affect the rain fell. Of this amount, 350 m3 was dis- hydrology of the bog itself. To further charged, 9 m3 was stored as groundwater, examine this issue, we attempted to char- and 41 m3 was stored in surface pools that acterize the nature and strength of the covered about 10% of the catchment area. hydrological linkage between a bog that The full accounting of the input, stor- has developed within a complex land- age, and discharge from two storms, one scape, and the adjacent forests, specifically of which followed a dry period, the other the CWHvh2/04 and /01 site series at the a wetter period, demonstrates the hydro- Diana Lake study site. logical independence of this bog system Water budgets for two rainfall events from adjacent ecosystems. During the first (July 22 and 28, 1999) were used to deter- event, most of the rainfall was accounted mine whether the bog experienced any for by the change in water storage within water inputs or exports. During the first the bog—almost no water was lost by sur- rainfall event, 17 mm of rain fell in face drainage through the stream. For the

3 (mm/h) Rainfall 1 (a) well at bog stream edge (ground surface at 171.3 m) –5 missing data

–10 average of 5 wells

–15

Water table relative table Water well on north side of bog

to ground surface ground to (cm) (ground surface at 173.1 m) –20 (b)

6 discharge (l/sec) over bog stream weir zero discharge 3

0 (c) Discharge (L/sec) Discharge 19 20 21 22 23 24 25 26 27 28 29 30 31 July 19–31, 1999

 . Hydrological parameters measured in a bog at the Diana Lake study site: (a) precipitation; (b) bog water table elevation relative to ground surface; and (c) discharge recorded at the bog weir.

38 second event, inputs were primarily water from the upland productive forest. accounted for by discharge and storage During rainfall events, up to 95% of the change (i.e., water table rise). water in the stream was routed through Despite the macro-scale topographic the swamp forest, though it only occupied connection between the bog and the adja- 25% of the catchment area (Fitzgerald et cent forested slope, no apparent hydrolog- al. 2003). This water was held in the ical linkage exists between them as seen by swamp forest before its release to the the lack of water inputs from these areas. stream. Between rainfall events, the pro- This lack of water transfer between the portion of water in the stream coming forest and bog is due to subtle differences from the swamp forest steadily declined as in elevation and flow paths at the margins the water table dropped. of these two systems. Seepage losses at the The upland productive forest also dis- foot of the forested CWHvh2/04 slope charged water into the stream via seeps. (Fitzgerald et al. 2003) are intercepted by a The discharge in these seeps was not sen- seepage channel that skirts the perimeter sitive to variation in the water table height of the bog on its northern side. Thus, if in the upland productive forest. The dis- forestry activities occurred on the slopes charge from the swamp forest, however, above this bog, the bog’s hydrological was sensitive to water table changes. This budget and its ecological integrity would indicates that harvesting activities on the be largely unaffected. The bog would upland productive forest will have less of incur little environmental damage, as long an effect on stream hydrology than har- as machinery did not traverse the bog, vesting of the swamp forest (Fitzgerald et including the bog margins. This bog, al. 2003). If these swamp forests are har- however, does not represent all peatlands vested, the water table could rise (Dubé et on the outer coast because this landscape al. 1995), decreasing available water stor- produces wetlands in many different top- age capacity, increasing peak water flows, ographical and hydrological settings. Each and potentially increasing the risk of specific situation must be properly inter- flooding (Fitzgerald et al. 2003). Our pre- preted before concluding that adjacent liminary results suggest that harvesting of ecosystems are hydrologically isolated. swamp forests should be avoided because of potentially negative on-site and off-site Swamp forest and hillslope interactions hydrological impacts. In the specific situa- Swamp forests (Western redcedar – Sitka tion at this study site, hydrological link- spruce – Skunk cabbage; CWHvh2/13 site ages exist between the hillslope productive series) are localized in water-receiving forest and the swamp forest. Therefore, areas such as lower slopes and depres- removal of the canopy on the hillslope sions. Although relatively common in the forest and the resulting interception and CWHvh2, these forests generally do not evaporative losses would have some cover extensive areas. Swamp forests were influence on the swamp forest below and recognized as being hydrologically con- indirectly affect stream flows. nected to other forest types, but the strength of this linkage was not known. 3.3.6 Results: soil water chemistry Mean A study carried out at Diana Lake was groundwater pH for all forest types com- designed to investigate the relationship bined was lower in the organic horizons between swamp forests and the adjacent than in the mineral horizons (Table 3.8). forests that provide water to them, in this The differences in soil water pH between case, an upland productive forest horizons is likely due to the acidic nature (CWHvh2/04). of coniferous forest litter, the acidifying This study showed that the swamp for- abilities of sphagnum and other mosses in est was fed by both ground and surface the organic layer, and the higher pH of

39 the mineral soil itself. In the mineral hori- /11, /12, and /32, respectively), while potas- zon, soil water pH was highest in the sium (K) was higher in the forested com- upland forest and lowest in the bog forest, munities (CWHvh2/01, /04, and /11) than though the differences were not statistical- the peatland communities (CWHvh2/12 ly significant. and /32) (Table 3.10) (Emili 2003). Vegetation type and soil type were Groundwater from mineral soils tended to important factors in the ionic makeup have higher concentrations of nutrients of groundwater; slope, water table depth, than that from organic soils (Table 3.11), and groundwater flow were not significant though the differences were not statistical- factors for any of the ions measured. ly significant. This indicates that ground- Productive forests (CWHvh2/04) had water contact with mineral soils accounts significantly higher concentrations of for the higher concentration of nutrients

bicarbonate (HCO3), sulphate (SO4), cal- in the forested vegetation types where cium (Ca), magnesium (Mg), and sodium organic horizons are shallower. Many ions (Na) than the lower-productivity scrub also tended to have higher concentrations forest, bog forest, bog woodland, and in the summer than in other seasons

open bog vegetation types (CWHvh2/01, (Table 3.12). At Diana Lake, nitrate (NO3),

 . Meana ionic composition of groundwater (mg/L) by site series at Diana Lake, 1997–1998 (adapted from Emili, 2003)

– – – – – – + + + + + + + + Site series HCO3 Cl NO3 NO2 PO4 SO4 Ca Mg Na K Fe Mn Al Zn Scrub forest (01) 10.5b 2.1 0.05 0.01 0.02 2.9b 1.5b 0.3b 2.6b 1.0b 0.6 0.03 0.4 0.2 Bog forest (11) 9.0b 2.5 0.04 0.01 0.01 < 1.04b 1.5b 0.9b 2.3b 1.2b 0.8 0.05 0.3 0.2 Bog woodland (12) 13.7b 1.6 < 0.02 0.01 0.01 < 1.04 2.7b 0.3b 1.9b 0.5a 0.9 0.01 0.1 0.3 Open peatland (32) 27.8b 1.5 < 0.02 0.01 0.02 1.9c 3.8b 0.5b 2.3b 0.6a 1.1 0.02 0.1 0.5 Upland forest (04) 35.0a 3.2 0.12 0.03 0.03 3.6a 10.2a 1.2a 3.2a 1.1b 0.0 0.03 0.1 0.0 a Means within a column followed by a different letter are significantly different (p < 0.05), n = 153. b “<” indicates concentration below specified detection limit c One sample above detection limit.

 . Mean ionic composition of groundwater (mg/L) in the organic and mineral subsoil horizons at Diana Lake, 1997–1998 (adapted from Emili, 2003)

– – – – – – + + + + + + + + Soil type HCO3 Cl NO3 NO2 PO4 SO4 Ca Mg Na K Fe Mn Al Zn Organic horizon 13.4 2.2 0.04a 0.02 0.02 1.9a 2.0 0.3 3.5 1.1 0.7 0.02 0.2 0.2 Mineral subsoil 16.0 2.1 0.07 0.02 0.02 3.3 2.6 0.4 3.8 0.8 0.6 0.03 0.3 0.3 a One sample above detection limit (n = 153).

 . Meana seasonal ionic composition of groundwater (mg/L) at Diana Lake, 1997–1998 (adapted from Emili, 2003)

– – – – – – + + + + + + + + Season HCO3 Cl NO3 NO2 PO4 SO4 Ca Mg Na K Fe Mn Al Zn Summer 20.7b 2.5b 0.12 0.01 0.02 2.3 2.9 0.6 3.6 0.9 1.6b 0.03 0.5b 0.9a Fall – 1.5ab < 0.02b 0.01 0.02 3.4 3.3 0.4 1.3 0.7 0.5a 0.03 0.2ab 0.1b Winter 12.1a 3.2a 0.4 0.01 0.01 < 1.04 1.3 0.2 2.9 0.9 0.4a 0.03 0.1a 0.2ab Spring 6.2b 1.4ab 0.5 0.01 0.01 3.7 1.3 0.3 2.7 1.3 0.2ab 0.02 0.2ab 0.1b a Means within a column followed by a different letter are significantly different (p < 0.05; n = 153). b “<” indicates concentration below specified detection limit.

40  sulphate, and phosphate (PO4) concentra- (i.e., less dilution). The was also tions were very low in the vegetation types highest in shallow groundwater, with where the water table was high and reduc- much lower values in the deep groundwa- ing conditions were present (Emili 2003). ter (Figure 3.15) (Gibson et al. 2000; Lortie Dissolved organic carbon concentra- 2002; Emili 2003). This pattern results tions differed with vegetation type (Table from the production of significant 3.8), season, and soil type. Dissolved amounts of  in the organic-rich organic carbon was higher in the swamp surficial deposits, and less in the underly- forest and open peatland than in the bog ing mineral soils (Schiff et al. 1990). In forest, bog woodland, and upland forest, addition, water that moves to deeper each having progressively lower values mineral layers loses some of its  by (Emili 2003). This pattern was likely due decomposition and absorption as it filters in part to the relative thickness of the down through the soil. The positive rela- organic horizon in the various vegetation tionship between  and discharge indi- types. Dissolved organic carbon was high- cates that, during rainfall events,  is est in summer, which is likely linked to flushed from the groundwater system to increases in microbial activity when tem- the stream. peratures are warmer and rainfall is less

28 (a) 24 (b) 20 0 Shallow hillslope 2 16 /s) 3 4 (mm/h) (mg/L)

12 0.5 6 Precipitation DOC 0.4 8 0.3 Stream 4 0.2 0.1 Deep hillslope 0 Stream discharge (m 0.0 61320273 61320273 May 6–June 3, 2000 May 6–June 3, 2000

 . Dissolved organic carbon () concentrations, rainfall, and stream discharge, Smith Island watershed: (a) stream, shallow hillslope, and deep hillslope DOC response to rainfall events; (b) rainfall and stream discharge response during the rainfall event.

3.4 Discussion 3.4.1 Watershed hydrology and canopy larger hydrological response and a shorter and Summary interception Rainfall event size and a lag time because of the smaller amount of watershed’s preceding moisture condition, available soil water storage capacity. Large especially its soil water storage capacity, rainfall events can produce larger hydro- control hydrological response and lag logical responses because a greater pro- time. Rainfall events must ﬁrst ﬁll the portion of the event’s water is surplus to available soil water storage capacity before available storage capacity and is discharged. producing a hydrological response. The Lag times for large rainfall events close- storage capacity is greater after a dry peri- ly match those for small events with cor- od than after a wet period. A small event responding preceding conditions, as soil preceded by a wet period produces a water storage capacity is not controlled by

41 the size of the event but by transpiration, however, indicates that 27% more rainfall evaporation, and discharge. The longer lag occurs at higher elevations (337 m). times after dry periods are a result of the About 55% of annual rainfall at the increased storage capacity, and produce a Diana Lake 72-m site resulted from events delayed hydrological response. larger than 40 mm, and 19% from events Hypermaritime watersheds such as 100 mm or larger, which indicates events those found in the CWHvh2 have a rela- producing large hydrological responses tively small amount of water storage occur regularly. This has important impli- capacity. The shallow, dominantly organic cations both for harvesting and road and soils typical of these watersheds have high drainage structure construction. The cur- water retention capacity, and are fre- rent precipitation shutdown guidelines quently saturated in this wet climate. The assume a daily drainage rate of 55 mm/day, small amount of available water storage and require a positive water balance of capacity in these soils means that signifi- 100 mm before shutdown. Precipitation- cant runoff is generated from relatively based operational shutdown guidelines small storms. A dense network of soil for the north coast are currently under macropores and pipes rapidly route the review (agra Earth and Environmental excess water downslope to stream channels. 1996; Price 2002); any new guidelines Compared with other locations, rainfall should recognize the influence of oro- events in the CWHvh2 produce a larger graphic rainfall in the mountainous hydrological response. Both the average watersheds of the region by ensuring that hydrological response of 0.41 and the rainfall is measured locally. largest response of 0.81 are high compared Topography, wind direction, and the with the weighted average of 0.20 record- spatial variability of rainfall events all con- ed for streams in the eastern United tribute to the rainfall patterns found in States, where the highest response was the Smith Island and Diana Lake water- between 0.40 and 0.50 (Hewlett 1982). In sheds. At Smith Island, the lower barriers contrast, hydrological response values of surrounding the monitoring sites are like- 0.55 (Cheng 1988) and greater than 0.90 ly responsible for the smaller orographic (Hetherington 1987) were recorded for effect. In addition, the southern part of individual rainfall events in British the island has higher elevations than the Columbia, and a value of 0.63 was record- northern part where the monitoring sites ed following a wet period in Barrow, are located. Consequently, moist southern Alaska (Dingman 2002). In the United air masses possibly lose some of their States studies, the 0.40 and 0.50 response moisture before reaching the monitoring values were found in locations with shal- sites on the north side of the island. The low soils and steep slopes (Dingman 2002), relationship between rainfall and elevation whereas the values recorded here were on is not always linear, however, and can be gentle terrain with mainly organic soils. influenced by local topography over short The high response on shallow slopes indi- distances. For example, although both are cates that the system has little storage at the same elevation, more rainfall is capacity and rapid water transfer mech- recorded at the Diana Lake mid-slope site anisms. compared with the hilltop site. This rain- Most rainfall and runoff information fall pattern may be produced as airflow for the forested watersheds along the accelerates over a barrier with a steep, north coast of British Columbia is based narrow upwind face, which results in on data collected at the Prince Rupert more rainfall on the leeward side of a Airport, which is located near sea level. mountain than on its hilltop (Daley et al. Rainfall data collected for this study, 1994).

42 We did not conduct a detailed exami- flooding (Lortie 2002). In small water- nation of the contributions of cloudwater sheds, however, the risk of greatly increased and fog drip as hydrological and nutrient peak flows is low (Beschta et al. 2000). inputs (see Emili [2004] for details of The introduction of additional water to rainfall, throughfall, and fog drip inputs a drainage system can be managed using and chemistry). Our sampling approach the current watershed assessment proce- did not permit the separation of simulta- dures for road building and bridge engi- neous occurrences of fog drip from driz- neering. By knowing the harvested area zle; however, other studies have shown and the watershed’s discharge characteris- that these sources of “occult precipita- tics, the increase in peak flows can be tion” represent significant inputs to identified and managed. coastal forests (e.g., Bormann et al. 1989; In eastern Canada, the increase in Harr 1982) and, therefore, this topic war- water on forested sites after harvesting rants more detailed study on the north is influenced more by interception than coast. by transpiration (Dubé et al. 1995). The decrease in canopy interception Preliminary estimates of transpiration after harvesting increases the amount of from the water balance studies of Maloney water received on the ground. At the two and Bennett (2002) and Beaudry and study sites, the canopy intercepted Sagar (1995) suggest that this is also the 20–25% of the average annual rainfall case in west coast hypermaritime ecosys- (i.e., for the May to November ice- and tems. Modified harvesting regimes will snow-free study period). If the areas are help to minimize the decrease in rainfall clearcut, the amount of water that must interception. Following regeneration of be removed by existing hydrological the harvested area, canopy interception processes can be expected to increase. A begins to increase again as trees grow. similar study found that interception after harvesting decreased by two-thirds when 3.4.2 Hydrological dynamics and linkages measured under the shrub layer (Roy et Hydrological dynamics differ among for- al. 2000); our measurements, however, est types. Our study shows that swamp were made above the shrub layer. The forests (CWHvh2/13) receive much of possible hydrological consequences of this their water input from other forest types, decreased interception include: and are important in mediating discharge • a decrease in time to peak flows after flows, whereas upland productive forests a storm; (CWHvh2/04) have deeper water tables • an increase in peak flow volumes; and mainly export water. Swamp forests, • an increase in water table height; and therefore, are more sensitive to harvest- • an increase in erosion, as natural ing-induced hydrological changes than drainage pipes reach capacity sooner upland productive forests; they should not and more overland flow occurs. be harvested because of their importance Although increased erosion of organic in receiving water and regulating soils (especially if the soil surface is dis- streamflow within a watershed, and their turbed) is possible due to their high water potential for increased water tables. retention and low cohesion qualities, the Upland productive forests are much less relatively gentle slopes on which these sensitive in these respects and could be low-productivity forests occur will experi- harvested with fewer on-site hydrological ence lower surface water runoff velocities, impacts. Off-site impacts to adjacent and thus lower off-site sediment trans- swamp forests, or other hydrologically port, than steeper hillslopes. Higher peak sensitive ecosystems, are still a potential flows in streams are also possible, which concern wherever direct linkages occur. may increase the risk of erosion and Upland scrub forests (CWHvh2/01) will

43 likely have an intermediate response, with by site preparation that includes soil mix- water tables rising slightly depending on ing and mounding (Shaw and Banner specific site and soil characteristics. These 2001a, 2001b); however, care must be taken scrub forests and their potential timber to avoid creating the conditions (e.g., pools values are currently of interest; therefore, beside mounds) that facilitate sphagnum future operational trials should monitor moss growth and paludification (Asada et and quantify any hydrological impacts. al. 2002). If forest regeneration is success- Some limited data on water table fluctua- ful, canopy interception will increase tions associated with harvesting scrub again as trees grow. In fast-growing New forests are available from the Port Simpson Zealand pine plantations, runoff parame- study site (Beaudry et al. 1994). The effects ters (e.g., peak flows, quick flows, and low are quite variable and apparently related flows) returned to pre-harvest levels 10 to local soil and topographic conditions, years after replanting (Fahey and Jackson as well as the location of skid roads that 1997). The rate of canopy development in act as local drainage pathways. Although harvested scrub forests of coastal British there was no significant difference be- Columbia is expected to be considerably tween average water table heights before slower, however. and after harvesting, in the wells located In a study of peak streamflows in rela- adjacent to skid trails, water tables tended tion to forest harvesting on eastern to drop; in the wells located away from Vancouver Island, Hudson (2002) used the skid trails, water tables tended to the concept of equivalent clearcut area rise. At the Oona River operational trial, () that accounts for hydrological re- although changes in water tables were not covery due to forest regeneration. He found measured, the relatively small areas of flat that the mean response to a decrease in and low-lying portions of the blocks were  of 10% (as sites regenerated) was a observed to have some surface ponding decrease in peak flow of 40–50%. after harvest that was not apparent pre- Forestry activities adjacent to wetlands harvest. involve possible hydrological effects, rang- A rise in water table could be an ing from the complete cut-off of water important ecological problem if scrub inputs to the wetland to a considerable forests are harvested. Smaller rainfall increase in water inputs. The magnitude events would saturate these forest soils of these effects will depend on the degree because of the reduced interception and to which the wetlands are hydrologically transpiration following canopy removal isolated. Decreases in water inputs could (Maloney et al. 2002; Dubé et al. 1995). result from constructing logging roads on A rise in water tables, or “watering up,” slopes that feed wetlands; increases in occurs in other forested wetland areas fol- water inputs (e.g., from the streams that lowing harvesting, especially on transi- feed wetlands) could result from remov- tional sites between wetlands and uplands ing the adjacent forest canopy. At both where the water table is deeper than in the extremes, these activities may initiate true wetlands (Dubé et al. 1995). Rises in changes in hydrology that could affect the water table will vary by forest type and wetland functioning and species composi- slope position. Higher water tables result tion. To avoid any negative effects, it will in less storage capacity in the soils, a shal- be necessary to assess whether the exten- lower aerobic rooting zone, a greater sive bog and other wetland ecosystems number of groundwater seeps, and altered typical of the CWHvh2 landscape are nutrient dynamics. Higher water tables hydrologically connected to areas planned also hamper regeneration and promote for harvest. Reconnaissance-level topo- paludification (Asada 2002). graphical and stream channel surveys are Regeneration success can be improved effective procedures in such assessments.

44 3.4.3 Soil pipes Our study results show existence, wetter surrounding ground that soil pipes play an important role in conditions and surface “blowholes” some- draining forests in the hypermaritime times divulge their location. Increases in north coast. The two contrasting study bulk density and moisture content, and sub-catchments had different water trans- decreases in hydraulic conductivity and port mechanisms, and harvesting will infiltration, commonly follow forest har- affect each differently. With its gentler vesting. The collapse and closure of slopes, the K-pipe basin will likely experi- macropores and soil pipes from harvest- ence a greater water table rise, and soil induced soil compaction is implicated as pipes will be most important in water the probable cause of higher bulk density transfer from the site. values (Herbauts et al. 1996; Miller et al. Soil pipes transport stormflow rapidly 1996; Williamson and Neilsen 2000). and efficiently; however, if harvesting Therefore, before harvesting, it is impor- damages these pipes, they could become tant to identify the most hydrologically “short-circuited,” decreasing their capaci- active zones and their spatial extent and ty to route stormflow through the land- connectivity within a basin. scape. Harvesting also reduces canopy After harvesting, and the subsequent interception, which may result in greater increases in water inputs discussed above, soil water inputs and thus more overland pipeflow will likely play a more important flow, higher peak discharge rates, and role in hillslope hydrology. Actions that shorter lag times (Ziemer 1992; Keppeler prevent soil pipes from collapsing (e.g., and Brown 1998). using slash to dissipate machine load or Soil pipes can contribute to soil stabil- minimizing the number of machine pass- ity in two ways: es) would help preserve their function 1. by increasing the rate of soil drainage; and connectivity, and maintain hillslope and drainage patterns. New soil pipes presum- 2. by limiting the development of ably form after existing ones are damaged, perched groundwater conditions although it remains unclear how long this (Uchida et al. 2001). process takes and to what extent the pipe If soil pipes become mechanically dam- network is restored. Studies of soil pipe aged and blocked, the increase in pore dynamics should be included in the water pressure could trigger landslides hydrological monitoring of future oper- (Ziemer 1992; Uchida et al. 2001), although ational trials. this is highly dependent on local hillslope conditions (Keppeler and Brown 1998). 3.4.4 Soil water chemistry The upland Even under natural conditions, landslides scrub forests of the north coast are may be triggered during large rainfall thought to form a transition between events when the capacity of the soil pipes productive upland forests and wetland is exceeded and pore water pressure forests. In Quebec, Dubé et al. (1995) increases rapidly (Uchida et al. 2001). In showed that forest types transitional Japan, pipe outlets were evident in several between upland forest and peatland are of the scars left by landslides that occurred those most susceptible to water table rises during heavy rainfall events. These land- after harvesting. As indicated earlier, how- slides occurred on various bedrock types ever, on the north coast, the water table and on slopes that ranged from 20 to 84% rise following harvesting in upland scrub (average 51%) (Uchida et al. 2001). forests is not expected to be as dramatic Soil pipes are particularly vulnerable to as in the swamp forests. disturbance because they lie hidden High water tables and the high levels beneath the soil surface. Although there is of acidity in peatland systems are signifi- often minimal surface expression of their cant limitations to the nutrient cycling

45 and forest productivity of these ecosys- 1989). If  increases a large amount tems. Nutrient availability is also limited after harvesting, water quality can be by phenolic acids, which inhibit mineral- affected in several ways, including: ization of nitrogen and phosphorus (de • increased water acidity, Montigny and Weetman 1990), and by • darker water with lower light penetra- high concentrations of lignins in cedar tion, and foliar litter (Prescott et al. 1995). • increased ability of the water to trans- A high water table limits nutrient avail- port metals (Davies-Colley and Vant ability, and thus site fertility (Paavilainen 1987; Driscoll et al. 1989; Driscoll et al. and Päivänen 1995), largely by restricting 1995). rooting depth and often by maintaining These changes may potentially lower anaerobic soil conditions. A high water drinking water quality and have an unde- table, therefore, controls redox conditions sirable effect on aquatic vegetation and and the cycling of some important nutri- ﬁsh populations. Dissolved organic car- ent ions. Under aerobic conditions, bon dynamics in pre- and post-harvest decomposing soil organic matter releases conditions requires further monitoring. nitrogen (N), sulphur (S), and phospho- If harvesting is to occur in sensitive water- rus (P), which are oxidized to the ions sheds where increases in  could have

NO3, SO4, and PO4, respectively (Devito important downstream impacts, options and Dillon 1993). During periods of high to minimize these effects (e.g., reducing water table, anaerobic conditions predom- the rate of harvesting) should be exam- inate, which prevents the oxidization of ined during the planning stages. nutrients to available forms. Our study A recent study of peatland and non- shows that the highest ion concentrations peatland watersheds in southeast Alaska in soil water occur in well-drained (pro- showed that peatland-dominated water- ductive forest) vegetation types which sheds had much higher average  have deeper water tables and thicker aero- concentrations in the streams than the bic zones. non-peatland watersheds (D. D’Amore, We collected  data only in a pre- U.S. Department of Agriculture, Juneau, harvest setting, and have relatively little Alaska, pers. comm., Dec. 2004). The post-harvest data available from similar researchers involved hypothesized that settings; therefore, our conclusions are the peatland streams were better adapted preliminary. After harvesting,  levels to handle an increase of  after harvest could increase along with the greater than the non-peatland systems, and that water inputs to a site (Maloney et al. the non-peatland systems were more sus- 2002). In addition,  concentrations ceptible to changes in stream biology are likely to rise as logging slash and resulting from increased  inputs after debris decomposes, and as microbial harvest. activity increases in the warmer soil Future operational trials in lower- (Moore and Jackson 1989). Dissolved productivity western redcedar–hemlock organic carbon concentrations in stream forests should include a soil water moni- waters may remain elevated for up to 8– toring program. Such a program could 10 years after harvest, although the results better quantify changes in water table from other studies in similar settings are levels and ion concentrations in soil and varied (Moore 1989; Moore and Jackson stream waters associated with harvesting.

46 4 ECOSYSTEM PROCESSES

4.1 Introduction Ecological plot data and field observations Core sampling at several sites was con- suggest that forest productivity on the ducted to reconstruct historical vegetation outer coast reflects the interactions of pattern and rates of peat accumulation. many site variables, such as soil depth, the Production and decomposition rates with- nature of surficial organic layers, the in present-day vascular plant and moss underlying mineral soil, bedrock geology, communities were measured to estimate soil hydrology, slope, and disturbance his- current rates of accumulation. These stud- tory. The ecosystem processes component ies included detailed measurements of of the HyP3 Project strives to understand annual sphagnum moss productivity and how and why each of these factors affect colonization on both disturbed and undis- site productivity and how they all interact turbed sites. to yield a specific forest ecosystem. This HyP3 research also included studies on information is essential to identify those bedrock, soil properties, and site produc- sites with potential for timber manage- tivity relationships in both old-growth ment, and to develop treatments that will and second-growth stands across the spec- maintain or improve site productivity. trum of site series, from bog woodland Organic matter dynamics, including and scrub forest, to productive upland rates of forest humus and peat accumula- forest. Studies assessing whether site tion, is an important ecosystem process manipulations to improve productivity on the outer coast where organic soil lay- are operationally feasible on lower- ers play a vital role in determining succes- productivity wetter sites are also under sional trends and site productivity. The way and are reported on in Chapter 6. many peatlands that characterize the Finally, a model of ecosystem develop- coastal landscape preserve a record of ment and productivity is presented. We past conditions in their pollen and macro- use this model to summarize the roles that fossil profiles. These profiles provide the bedrock geology, soil drainage, and dis- data against which we can compare cur- turbance history play in ecosystem devel- rent conditions, and predict future hydro- opment in the CWHvh2. This model logical and related ecosystem responses to represents a synthesis of the many indiv- natural and human-influenced disturbances. idual findings of this project.

4.2 Succession Our research on the role of succession of plant communities over time, ultimate- and Disturbance and disturbance in vegetation dynamics ly leading to a climax or relatively stable will help to determine whether the lower- vegetation type. This process is often productivity western redcedar-dominated accompanied by changes in soil composi- forests of the north coast can be harvested tion and hydrology, which may be initiat- and regenerated sustainably. Understanding ed by the vegetation itself, especially in ecological processes, such as succession wetlands. Bog development is an extreme and disturbance, is critical to this determi- case where the buildup of organic matter nation because of the close ecological rela- over hundreds or thousands of years (i.e., tionship between forests and bogs on the paludification) can produce conditions north coast, and the importance of distur- detrimental to tree growth. The gentle ter- bance in controlling bog and forest suc- rain of the Hecate Lowlands on the outer cession. north coast, with its combination of high Ecological succession is defined as the levels of precipitation and low levels of change in species composition and cover disturbance, favours paludification and

47 bog development. This process is slowed coast and other less maritime areas of on steeper terrain, where adequate soil British Columbia. In most interior ecosys- drainage, slope instability, and occasional tems of the province, successional path- windthrow events tend to retard organic ways following disturbance (mainly fire) matter buildup and maintain forest pro- lead to a climax of productive forest. On ductivity. Research suggests that sustain- the outer north coast, however, research able forestry is only possible on sites suggests that the main long-term succes- where the natural inhibition of tree sional pathway, especially on the subdued growth has not progressed too far and will landscape of the Hecate Lowlands, is not be promoted by harvesting practices. from upland productive forest to lower- This section summarizes the relationship productivity forest types, and eventually between natural disturbance and succes- to open bog (Klinger 1996). This successional trends on the north coast. sional pattern is not unique to the northwestern coast of North America. Other 4.2.1 Successional trends Evidence sug- hypermaritime areas where sloping gests that the plant communities of the blanket bogs are extensive include outer north coast have long-term succes- Newfoundland, Great Britain, Ireland, sional linkages. Successional histories Scandinavia, southern Chile, and south- spanning thousands of years are recon- western New Zealand (Moore and structed by analyzing the peat stratigraphy Bellamy 1974). In the United Kingdom, of bogs using pollen, spores, and plant forest-clearing activities may have played remains in peat cores, and radiocarbon an important role in the development of (C14) dating. Cores collected by Banner et open blanket bogs over large areas that al. (1983) near Prince Rupert show an were formerly forested (Moore 1987). 8000-year sequence, from an initial shore pine–red alder pioneer forest, to a Sitka 4.2.2 The role of climate in succession spruce–western hemlock productive allu- Based on studies of peat stratigraphy, evi- vial forest, then to a western redcedar– dence suggests that a period of peatland yellow-cedar scrub forest, and finally to a expansion, triggered by a cooler and wet- shore pine–yellow-cedar–western hemlock ter climatic trend, occurred during the bog woodland. Some areas have shown middle part of the Holocene. Estimates of further changes from the bog woodland when this expansion began range from to the open bog stage (Turunen and 3500 to 6000  (Heusser 1960; Mathewes Turunen 2003). This shift in productivity and Heusser 1981; Banner et al. 1983; and biomass allocation from trees to Hebda 1995) (Figure 4.1). On the north bryophytes appears to represent the domi- coast, this cooler and wetter trend was nant successional direction on the gentle evidently sufficient to trigger succession slopes of the outer north coast. Some from productive forest to scrub forest, areas, however, show productive forests thus setting the stage for the development growing over peat deposits, which indi- of the blanket bog communities that char- cates that succession from wetland to for- acterize much of the area today. est also occurs on certain sites (Banner et al. 1983). Based on C14 dating, one such 4.2.3 The role of disturbance in succes- transition from wetland peat to upland sion Natural disturbance events on the forest humus in the Rainbow Lake area north coast, as described in Chapter 2, near Prince Rupert began approximately play an important role in slowing and 2100  (before present) (Banner et al. reducing organic matter accumulation on 1983). specific types of sites. The main types of These successional trends highlight an natural disturbance on the north coast are important difference between the north landslides, windthrow, and fluvial activity.

48 Warm dry period Warm wet period 4 Relative temperature Relative precipitation 3

2 Present conditions

C) and precipitation (no scale) 109876543210 o –1

–2

Temperature ( Temperature Cool wet period –3 Years BP ('000s)

 . Historical climatic conditions on the north coast relative to present conditions (interpreted from Hebda, 1995).

These disturbance agents may cause large- studied in other parts of the world. There scale, catastrophic (stand-replacing) is growing scientific evidence from tropi- disturbances or more localized gap distur- cal, temperate, and boreal zones that an bances. The churning of soil that occurs ecosystem “decline phase” is associated when a root wad is turned up or a land- with the long-term absence of catastroph- slide occurs speeds the decomposition of ic disturbance (Wardle et al. 2004.) accumulated organic materials, brings Although most researchers agree that mineral soil to the surface, and prevents windthrow is an important disturbance or reverses hardpan formation (Bormann agent on the coast, only limited documen- et al. 1995; Kayahara and Klinka 1997). tation (especially for the north coast) After a windthrow disturbance, new exists concerning the extent of occur- organic horizons on the exposed tree root rence, return intervals, and the degree to mounds can form at rates almost on par which windthrow contributes to soil mix- with those of long-term peat accumula- ing across the landscape. A recent study in tion in peatlands (Bormann et al. 1995; southeast Alaska (Hennon and McClellan Turunen and Turunen 2003). Without 2003) found that many forests have no regular disturbance, this organic matter evidence of catastrophic windthrow, and could continue to accumulate to consider- that most tree death leading to canopy gap able depths. Studies in southeast Alaska formation does not involve windthrow, or suggest that a disturbance return period of the uprooting necessary to cause soil mix- less than 200–350 years is needed to pre- ing. For example, in areas of high wind vent tree roots from being confined to an exposure, more than 80% of the canopy- increasingly thick organic horizon level gap makers were either dead-standing (Bormann et al. 1995). Longer disturbance trees or had snapped off, neither of which return intervals may result in paludific- contribute to soil mixing. In contrast, ation and declining forest productivity. Bormann et al. (1995) found good evi- This relationship between disturbance and dence at several sites in southeast Alaska ecosystem productivity has also been that windthrow played an important role

49 in soil mixing and the reversal of paludifi- Islands revealed a 15 times greater rate of cation processes. Clearly, these studies occurrence on human-modified terrain require duplication and expansion on the than on forested terrain (Banner et al. north coast of British Columbia to better 1989). The effects were greatest in areas of quantify the extent and effects of wind- large clearcuts and road networks. In the throw as both a small scale and cata- natural forest landscape, mass wasting strophic disturbance agent. events are spread out in time and space, and are partially responsible for maintain- 4.2.4 Management implications ing forest productivity. Where landslide Successional dynamics on the outer north activity is accelerated by human activities, coast has implications for forest manage- however, negative effects often result, such ment, both in the currently operable, pro- as regeneration delays, initial loss of productive forests and the lower-productivity ductivity near the slide source where soil western redcedar-dominated scrub forests, is scoured to bedrock, and sediment load- where little harvesting has occurred to date. ing and scouring of aquatic habitat. These On the productive, currently operable very visible and immediate impacts tend sites, activities such as suspension cable to outweigh any potential improvement logging and helicopter logging, which to long-term productivity that may occur minimize surface disturbance and pro- in downslope areas. One of the major mote the development of young wind- challenges we face is managing human- throw-resistant stands, may result in induced disturbances on a site-specific declining forest productivity over time. basis and in a way that attempts to mimic In this case, forest harvesting could act to the natural system. Another challenge is lengthen the disturbance-return interval, gaining public acceptance that distur- and thereby reduce mineral soil disturbances, whether natural or human- bance, allowing organic matter to accu- induced, can have positive as well as mulate without the setbacks caused by negative impacts on ecosystems. windthrow-induced mixing of mineral In the lower-productivity forests that and organic horizons (Bormann et al. have escaped major disturbance events for 1995). This lack of disturbance could set thousands of years, harvesting and site the forest on a trajectory of organic matter preparation activities may provide the accumulation that would be difficult to necessary surface disturbance and soil alter, especially where forests are managed churning to mix mineral and organic on shorter rotations (≤ 100 years) which horizons, improve nutrient availability pre-empt the natural windthrow distur- and soil aeration, and retard organic mat- bance cycle. ter accumulation. Given the appropriate On steep slopes susceptible to mass site conditions (i.e., surface organic hori- wasting (e.g., landslides, and debris flows), zons underlain by mineral soil), such however, forest harvesting and road build- activities may improve tree productivity. ing may promote excessive disturbance This mixing may not be possible or with potentially negative effects on pro- beneficial, however, on sites with deep ductivity, especially in the short term (see organic soils, or where mineral soils are Figure 1.4). Studies on Haida Gwaii/the very shallow or absent. Differences in soil Queen Charlotte Islands show that timber properties and site productivity often harvesting can leave hillslopes susceptible reflect differences in bedrock geology. to accelerated rates of mass wasting for Mineral soils are often thinner over hard, 15–20 years following harvesting, or until massive granitic rocks than over softer stabilizing root systems re-establish. A metamorphic rocks, especially the schists comparison of mass wasting rates on the (see section 4.5.1 for more detail). If tim- steep west coast of the Queen Charlotte ber harvesting expands into these lower-

50 productivity forests, candidate sites must growth regeneration and productivity. be carefully assessed using speciﬁc site See Chapter 6 for details about the treat- and stand criteria so that any treatments ments applied in operational trials near applied will ensure acceptable second- Prince Rupert.

4.3 Paludification One of the most significant concerns mounding is used in wet forests to pro- and Vegetation regarding forest harvesting activities on duce plantable sites, and to increase tree Dynamics lower-productivity, western redcedar- survival and growth (Londo 2001; Shaw dominated sites is site degradation and and Banner 2001a). This treatment, how- reduced forest productivity. This concern ever, can result in adjacent wet depres- is particularly relevant in north coastal sions, which may facilitate the invasion of British Columbia because paludification sphagnum mosses and the paludification appears to have extended wetlands into of previously forested ecosystems; there- formerly productive forests (Banner et al. fore, it is imperative to understand the 1983). Paludification is influenced by sev- ecological relationship between moss eral factors including soil physical and growth and forest dynamics, and how this chemical properties, long-term plant suc- relationship is affected by forest manage- cession, and climatic changes. In several ment practices. parts of the world, human activities, such To create a more complete picture as forest clearing and agriculture, also play of how plant species, climate, micro- a role in promoting paludification (Moore topography, and ultimately site productiv- 1987; Warner et al. 1989). Forest clearing ity interact on the scrub forest sites of the removes the rain-intercepting canopy and north coast, this section summarizes decreases evapotranspiration. This may information from Asada (2002), Asada et cause a rise in the water table, facilitate al. (2003a, 2003b), Asada et al. (2004), and the invasion by peat-forming sphagnum Asada and Warner (2005). It describes a mosses, and potentially retard decomposi- series of experiments carried out at the tion in saturated organic horizons. Diana Lake and Port Simpson study sites Mosses are a major component of the (Figure 2.9) that deal with moss ecology, vegetation in the hypermaritime, and peat paludification, and vegetation and envi- accumulations are composed primarily of ronment relationships. These experiments the remains of mosses mixed with sedges set out to: and other vascular plants. The response of • provide quantitative estimates of the mosses to forest management practices is growth and production of mosses and of interest because of possible interactions peatland community types on the outer with forest productivity and long-term coast of British Columbia; vegetation successional pathways. Peat • compare decomposition rates in differ- accumulates when moss production ent community types; exceeds decomposition rates. To deter- • document vegetation and environment mine the peat accumulation potential of relationships in natural and post- an area, measurements of productivity harvest communities; and decomposition rates are necessary. • examine the possible effects of forest Acquiring this baseline information for management practices on moss growth natural peatlands will be useful for com- and productivity; and parisons with managed areas. • examine the effect of harvesting and Site preparation following harvesting mounding activities on vegetation, may further promote the invasion of especially sphagnum mosses, at the Port sphagnum mosses. Throughout British Simpson operational trial. Columbia and in many other areas,

51 4.3.1 Study approach Each of the study were examined to determine the likely areas required a baseline classification of changes at the harvested Port Simpson vegetation communities to provide a site. framework for further vegetation and Moss productivity was determined environment studies. The cover of all using nine abundant moss species at the plant species was recorded in quadrats Diana Lake site: Sphagnum austinii along transects within the Diana Lake (Austin’s peat-moss), S. fuscum (common and Port Simpson study sites. These brown peat-moss), S. rubellum, S. papillo- quadrats were grouped by classification sum (fat peat-moss), S. lindbergii (brown- analysis (Two-Way INdicator SPecies stemmed peat-moss), S. tenellum (soft ANalysis – ; Hill 1979) into peat-moss), S. pacificum, Racomitrium plant communities for each study area. lanuginosum (hoary rock-moss), and Multivariate ordination analyses (detrend- Pleurozium schreberi (red-stemmed feath- ed correspondence analysis [] and ermoss). The selected mosses are the most canonical correspondence analysis []; representative peatland species in the Hill and Gauch 1980; ter Braak 1986) region and have fairly specific habitat revealed the relationship between the preferences (Table 4.1). Their growth was resulting plant communities and the envi- measured periodically and compared with ronment.7 Environmental variables local climatic parameters. included water table and water chemistry Growth measurements for all species measures, physical soil property measures, were made at approximately 2-week and slope. The Port Simpson study was intervals from May through August in conducted 8 years after harvesting and site 1999, and again on November 19, 1999. preparation treatments. As no comparable Measurements for R. lanuginosum and P. pre-harvest data existed for the plant schreberi were also taken on July 11, 2000, communities there, those of Diana Lake and again on June 5, 2001. Winter growth

 . Growth and production of sphagnum and other mosses and their correlation with climatic parameters (adapted from Asada et al. 2003a)

Correlation Correlation Correlation with mean with mean with Productiona daily daily Climatic Species Habitat preference Growtha (mm) (g/m2) precipitationb temperature Indexb Sphagnum austinii Large hummock 10 ± 3c 280 ± 80a 0.15 0.03 0.35 S. fuscum Large hummock 16 ± 4b 310 ± 70a 0.60 –0.24 0.72* S. rubellum Small hummock 15 ± 3b 220 ± 50ab 0.85** –0.60 0.81* S. papillosum Wet hummock 21 ± 4b 150 ± 50ab 0.75* –0.38 0.76* S. tenellum Around pools and wet lawns 15 ± 4b 110 ± 40ab 0.84** –0.39 0.88** S. paciﬁcum Wet lawns 52 ± 9a 230 ± 50ab 0.74* –0.30 0.88** S. lindbergii Depressions and small streams 43 ± 11a 260 ± 80a 0.73* –0.27 0.82* Racomitrium Dry mounds in bog 9 ± 1–10 ± 1 360 ± 40–410 ± 50 0.59 0.18 0.95** lanuginosum Pleurozium schreberi Bog woodland 20 ± 2–23 ± 3 290 ± 60–320 ± 80 0.47 0.25 0.89** a Growth and production for sphagnum mosses was estimated from May 21 to November 18, 1999; for other mosses the first-year growth (i.e., 1st number) is from July 16, 1999 to July 11, 2000, and the second-year growth (i.e., 2nd number) is from July 11, 2000 to June 5, 2001. Values are means ± standard error. Means followed by a different letter are significantly different (Tukey’s HSD, p < 0.05, tested among sphagnum mosses only). b Correlation between moss growth and climatic parameters is shown using Pearson correlation coefficients (*p < 0.05; **p < 0.01).

7 Refer to Asada et al. (2003b) for further details on classification and ordination approaches used in this study.

52 measurements for sphagnum species were was developed to reflect the following impossible because of interference from assumptions, which were expected from snow; therefore, winter growth was esti- previous studies: mated by using the relationship between • Growth of mosses is controlled prim- the growth and the climate derived from arily by precipitation. the climatic index (described below). • Precipitation cannot contribute to the Estimated winter growth was added to moss growth if temperatures are lower summer growth to obtain estimates of than a certain threshold. annual growth; however, winter growth • The higher the temperature (up to estimates do not take into account solar moderate temperatures), the more pre- radiation differences between summer cipitation relates to growth. and winter. Other concerns about esti- The climatic index adjusts the precipi- mates of winter sphagnum growth are tation for each day by the temperature for outlined in Asada et al. 2003a. that day. When the temperature is lower The climatic index produces a regres- than a set threshold, the amount of pre- sion equation for each sphagnum species, cipitation is adjusted to zero, while pre- and the winter growth was then estimated cipitation on warmer days receives an by inserting winter climate data into the increased weighting, based on the number equation. Note that the estimated values of degrees above the threshold. for hummock-forming sphagnum species Moss growth and all climate parame- should be treated with caution because ters were expressed as means per day in a the correlation coefficients between the given period. Correlation coefficients growth and the climatic index, though between the growth and each climate high, were not significant. Annual pro- parameter (i.e., precipitation, tempera- duction of each moss per unit area was ture, and climatic index) were calculated estimated by multiplying the average for each species. See Asada et al. (2003a) annual linear growth by the average mass for a more detailed description and math- per unit length (Table 4.1). ematical formula for the climatic index. To quantify concerns about paludi- Measurements of current year’s growth fication, the growth rates of three sphag- for the major herb, shrub, and lichen num species (S. pacificum, S. rubiginosum, species, and the moss productivity data and S. rubellum) were measured at Port described above, were used to determine Simpson and compared with those in ecosystem productivity in the five com- unharvested areas at Diana Lake. Snow munity types found in the open peatland compression led to problems in measur- at Diana Lake (Asada 2002). Below- ing sphagnum growth; the maximum ground productivity was estimated growth values were considered more accu- using root to shoot ratios found in other rate than mean values, and were therefore studies. The productivity of the entire used for comparison purposes. In addi- peatland was estimated by applying a tion, the annual changes in area and weighting to the production by the per- volume covered by mosses, especially cent cover of each community type within sphagnum, were measured at three Port the peatland. To estimate long- and short- Simpson locations. term peat accumulation rates, radiocar- Daily precipitation, and daily mean, bon and 210Pb dating techniques were maximum, and minimum temperatures applied to surface cores collected from were obtained from the meteorological the Diana Lake study site (Turunen and station in the open bog of the Diana Lake Turunen 2003; Asada and Warner 2005). site. These climate variables were treated The decomposition rate of organic as single parameters and also combined material (Sphagnum fuscum was used as a for the climate index. The climate index standard material) was measured in nine

53 plant communities at Diana Lake (e.g., forested communities were found in areas bog woodland, bog forest, scrub forest, of greater slope and (at least seasonally) upland forest, and open peatland, which lower water tables. Although these two was further subdivided into five commu- parameters are interrelated, steepness of nity types) and the four plant communi- slope influenced site drainage and soil ties that were identified at Port Simpson. water flux, and the water table influenced Organic matter placed in mesh bags was aerobic soil conditions and water chem- buried at a 10 cm depth in all plant com- istry. The distribution of productive forest munities, and also at a 25 and 45 cm depth (CWHvh2/04) on axis 2 correlated with in the bog woodland and open peatland at the maximum level of groundwater table Diana Lake. Bags were removed after 1 fluctuation and higher soil water conduc- and 2 years of incubation, and analyzed tivity parameters. This plant community for mass loss and changes in carbon and grows in areas with consistently good nitrogen content. drainage and is more influenced by groundwater in contact with mineral 4.3.2 Results: plant communities The soils.  classification of quadrats at At the Port Simpson operational the Diana Lake research site identified trial site, four plant communities were nine plant communities. These communi- identified: two were related to wet ties were analogous to some of the site hollows (Sphagnum angustifolium and series identified by Banner et al. (1993) S. pacificum); one was related to relatively (see section 5.2), except that the open bog dry (mesic) mounds (Cornus canadensis – community was further subdivided into Hylocomium splendens); and one was five sub-communities (Table 4.2). Site intermediate in moisture (Polytrichum for- series at Diana Lake include: Western mosum – Sphagnum girgensohnii)(Table hemlock – Sitka spruce – Lanky moss 4.3). The unmounded area contained only (CWHvh2/04–productive forest), Western one plant community that is generally redcedar – Western hemlock – Salal related to mesic areas—Cornus canadensis (CWHvh2/01–scrub forest), Yellow-cedar – Hylocomium splendens. The mounded – Western redcedar – Goldthread area contained a mixture of all four com- (CWHvh2/11–bog forest), Shore pine – munities, reflecting the altered micro- Yellow-cedar – Sphagnum (CWHvh2/12– topography created by the mounding bog woodland), and Non-forested slope – treatment. blanket bog (CWHvh2/32); sub-commu- The plant communities associated with nities identified within the open bogs were the mesic mound and the intermediate Menyanthes trifoliata pool, Carex utricula- moisture areas at Port Simpson were simi- ta – Sphagnum lindbergii depression, lar to those of the natural forest site at Rhynchospora alba – S. tenellum lawn, Diana Lake, while the two sphagnum- Racomitrium lanuginosum hummock, and dominated communities were very differ- S. austinii hummock. ent from those at Diana Lake. This An ordination of sample plots from the suggests that the species in these commu- above plant communities is presented in nities are responding to habitat changes Figure 4.2. Sample plots of similar species induced by forest management; the two composition and cover are clustered on sphagnum species that dominate the wet this graph. The distribution of plant com- hollows are not commonly found in munities on axis 1 correlated best with forested areas and therefore likely colo- the minimum level of groundwater table nized the site after harvesting. These fluctuation and slope. For example, open sphagnum-dominated communities were bog communities were found in areas of located mainly in fens in the larger Diana little slope and high water table, and Lake area. A paleoecological study

54  . Vegetation classiﬁed at the Diana Lake study site by Two-Way INdicator SPecies ANalysis (TWINSPAN) (adapted from Asada et al., 2003b)

Communitya C1 C2 C3 C4 C5 C6 C7 C8 C9 Number of plots 3 5 5 11 5 9 14 9 5 Species name Stratumb

Trees Abies amabilis (Dougl. ex Loud.) Dougl. ex Forbes 9 5.0c – –––––– – 8 0.7 0.6 – – – – – – – 7 1.7––––––– – 6 1.7––––––– – 5 1.3––––––– – 4 2.0––––––– – Tsuga heterophylla (Raf.) Sarg. 9 5.0 – – – – – – – – 8 3.3 3.6 – – – – – – – 7 2.3 4.0 0.8 0.3 – – – – – 6 3.7 3.8 2.4 0.3 – – – – – 5 2.0 – 1.2 – – – – – – 4 1.7 0.4 – – – – – – – Picea sitchensis (Bong.) Carr. 9 –0.6–––––– – 8 –0.8–––––– – 7 –1.2–––––– – 6 –1.2–––––– – 5 –0.4–––––– – Tsuga mertensiana (Bong.) Carr. 8 –2.6–––––– – 7 – 1.0 1.8 – – – – – – 6 ––1.2–––––– 5 – 0.2 0.8 – – – – – – Thuja plicata Donn ex D. Don 9 2.3 1.6 – – – – – – – 8 – 4.4 0.4 – – – – – – 7 – 2.6 2.2 – – – – – – 6 – 1.2 0.6 – – – – – – 5 – 0.2 1.6 – – – – – – 4 –0.6–––––– – Chamaecyparis nootkatensis (D. Don) Spach 8 – 1.6 1.0 – – – – – – 7 – 1.4 2.8 – – – – – – 6 – 0.4 2.6 – – – – – – 5 – – 3.2 2.2 – 0.4 – – – 4 – 1.0 3.2 1.0 1.0 – – – – Pinus contorta Dougl. ex Loud. var. contorta 8 ––1.4–––––– 7 – – 3.0 0.9 – – – – – 6 – – 0.2 1.7 – 0.4 – – – 5 – – 1.4 – – 0.7 – – – 4 – – – 0.3 – 0.6 – – –

Shrubs Vaccinium parvifolium Sm. 6 3.3 0.2 – – – – – – – 5 0.7 0.6 0.8 – – – – – – 4 1.7 1.0 0.8 – – – – – – Oplopanax horridus (Smith) Miq. 6 1.0 0.8 – – – – – – – 5 0.3 0.2 – – – – – – – 4 0.7––––––– – Vaccinium alaskaense Howell 6 2.0 4.0 – – – – – – – 5 1.0 0.6 1.2 – – – – – – 4 0.3 1.8 1.0 – – – – – –

55  . Continued

Communitya C1 C2 C3 C4 C5 C6 C7 C8 C9 Number of plots 3 5 5 11 5 9 14 9 5 Species name Stratumb

Shrubs Menziesia ferruginea Sm. 6 – 4.0 1.2 – – – – – – 5 1.7 – 1.0 – – – – – – 4 – 0.6 0.4 – – – – – – Vaccinium ovalifolium Sm. 6 – 1.8 – – – – – – – 5 – 1.0 1.4 – – – – – – 4 – 0.4 – – – – – – – Gaultheria shallon Pursh 5 – 2.6 0.6 0.2 – – – – – 4 – 2.0 3.4 0.3 – – – – – Ledum groenlandicum Oeder 4 – – 2.0 1.5 1.4 1.2 0.1 0.1 – Myrica gale L. 5 – – – 0.3 – – – – – 4 – – – 0.5 – – – – – Vaccinium uliginosum L. 4 – – 0.4 1.5 0.4 1.3 0.1 – – Juniperus communis L. 4 – – – 1.1 0.8 1.3 0.1 – – Kalmia microphylla (Hook.) Heller occidentalis 4 – – 1.4 1.5 1.0 1.9 0.3 0.8 – (Small) Taylor & MacBryde

Herbs and Dwarf Shrubs Cornus canadensis L. 3 2.3 3.4 3.4 1.5 1.2 1.1 – 0.1 – Tiarella trifoliata L. 2 1.7 – – – – – – – – Rubus pedatus J. E. Sm. 3 1.0 1.8 0.2 – – – – – – Listera cordata (L.) R. Br. 2 0.7 1.0 0.4 – – – – – – Streptopus lanceolatus (Ait.) Reveal var curvipes 2 0.3 0.8 0.4 – – – – – – (Vail) Reveal. Lysichiton americanus Hult. & St. John 2 – 2.2 – – – – – – – Moneses uniflora (L.) A. Gray 2 – 0.4 – – – – – – – Linnaea borealis L. 3 – 1.6 1.4 0.5 – – – – – Coptis aspleniifolia Salisb. 2 – 1.6 1.8 0.1 – – – – – Vaccinium vitis–idaea L. ssp. minus (Lodd.) Hult. 3 – – 1.4 0.4 – – – – – Vaccinium caespitosum Michx. 3 – – 1.8 – – – – – – 4 – – 1.4 0.3 0.2 – – – – Fauria crista–galli (Menzies ex Hook.) Makino 2 – 0.4 3.8 3.2 0.4 – – – – Rubus chamaemorus L. 3 – – 0.2 0.6 0.8 – – – – Oxycoccus oxycoccus (L.) MacM. 3 – – 0.2 1.0 0.6 0.6 0.1 0.4 – Sanguisorba officinalis L. 2 – – 1.2 2.1 0.4 2.0 0.6 1.4 0.2 Drosera rotundifolia L. 2 – – 1.0 2.2 2.0 0.6 2.9 2.0 – Empetrum nigrum L. 3 – – 1.0 1.8 1.8 0.9 0.1 – – Trientalis europaea L. ssp. arctica (Fisch. ex Hult.) Hult. 2 – – 0.4 0.8 0.2 0.7 0.1 0.2 Andromeda polifolia L. 3 – – 0.2 1.0 0.6 1.4 1.1 1.1 – Trichophorum cespitosum (L.) Hartm. 2 – – 0.2 1.7 1.2 2.0 0.1 1.0 – Eriophorum angustifolium Honck. 2 – – 0.2 1.4 0.2 1.7 1.1 1.0 3.0 Coptis trifolia (L.) Salisb. 2 – – 0.2 1.1 0.4 0.8 – 0.2 – Carex livida (Wahlenb.) Willd. var. radicaulis Paine 2 – – 0.2 0.7 0.2 0.1 – 1.0 1.0 Rhynchospora alba (L.) Vahl 2 – – – 0.9 – 1.6 3.4 1.6 1.2 Triantha glutinosa (Michx.)Baker 2 – – – 0.7 0.4 – 0.1 0.2 – Carex pauciflora Lightf. 2 – – – 0.5 – 0.1 – 0.6 – Gentiana douglasiana Bong. 2 – – – 0.4 – 0.6 – 0.2 – Dodecatheon jeffreyi van Houtte 2 – – – 0.3 – – – 0.8 – Geum calthifolium Menzies ex J. M. Smith 2 – – – 0.2 – – 0.1 0.6 –

56  . Continued

Communitya C1 C2 C3 C4 C5 C6 C7 C8 C9 Number of plots 3 5 5 11 5 9 14 9 5 Species name Stratumb

Herbs and Dwarf Shrubs Agrostis aequivalvis (Trin.) Trin. 2 – – – 0.2 – 0.1 – 0.3 – Drosera anglica Huds. 2 – – – – 1.0 0.1 2.7 0.4 – Carex pluriﬂora Hult. 2 – – – – – 0.2 0.2 0.9 0.8 Carex utriculata Boott 2 – – – – – 0.1 – 2.2 0.2 Scheuchzeria palustris L. ssp. americana (Fern.) Hult. 2 – – – – – – 0.3 0.1 0.2 Menyanthes trifoliata L. 2 – – – – – – – 0.9 4.6

Ferns / Clubmosses Gymnocarpium dryopteris (L.) Newman 2 1.3 – – – – – – – – Polystichum munitum (Kaulf.) K.B. Presl 2 0.7 – – – – – – – – Blechnum spicant (L.) Roth 2 1.3 1.6 – – – – – – – Lycopodium annotinum L. 2 – 0.4 1.2 0.4 – – – – –

Bryophytes Rhytidiadelphus loreus (Hedw.) Warnst. 1 4.7 2.4 3.0 0.2 – – – – – Rhizomnium glabrescens (Kindb.) T. Kop 1 2.7 1.8 1.6 – – – – – – Hylocomium splendens (Hedw.) Schimp. 1 2.7 4.2 3.0 0.1 – – – – – Eurhynchium oreganum (Sull.) Jaeg. 1 2.3 0.2 – – – – – – – Sphagnum rubiginosum Flatb. 1 1.7 4.0 – – – – – – – Scapania bolanderi Aust. 1 1.3 0.2 – – – – – – – Plagiothecium undulatum (Hedw.) Schimp. 1 1.0 1.0 0.8 0.1 – – – – – Plagiochila porelloides (Torr. ex Nees) Lindenb 1 0.7 1.0 0.2 – – – – – – Riccardia latifrons Lindb. 1 0.3 0.2 – – – – – – – Hookeria lucens (Hedw.) Sm. 1 0.3 0.8 – – – – – – – Sphagnum paciﬁcum Flatb. 1 – 2.6 3.2 1.7 – – – – – Pellia neesiana (Gott.) Limpr. 1 – 1.0 0.2 – – – – – – Sphagnum papillosum Lindb. 1 – 0.4 0.2 1.0 – 1.0 1.1 2.2 – Sphagnum magellanicum Brid. 1 – 0.4 – 0.2 – – – – – Calypogija sphagnicola (H. Arnell & J. Perss.) 1 – 0.4 – 0.1 – – – – – Warnst. & Loeske Sphagnum capillifolium (Ehrh.) Hedw. 1 – 0.2 2.6 1.5 – – – – – Pleurozium schreberi (Brid.) Mitt. 1 – – 3.0 1.5 – – – – – Sphagnum rubellum Wils. 1 – – 1.8 2.5 1.6 1.4 0.9 0.7 – Sphagnum fuscum (Schimp.) Klinggr. 1 – – 1.6 3.2 1.0 1.6 0.4 – – Bazzania trilobata (L.) S. Gray 1 – – 1.6 0.3 – – 0.1 – – Sphagnum tenellum (Brid.) Bory 1 – – 1.0 0.5 – 0.7 3.4 1.1 – Hypnum callichroum Funck ex Brid. 1 ––1.0–––––– Hepatophyta (Jungermanniales) spp. 1 – – 0.8 – – – – – – Dicranum majus Sm. var. majus 1 ––0.8–––––– Ptilium crista–castrensis (Hedw.) De Not. 1 – – 0.4 0.5 – – 0.1 – – Aulacomnium palustre (Hedw.) Schwaegr. 1 – – 0.4 – – – – – – Sphagnum recurvum P. Beauv. 1 – – 0.2 0.5 – – – – – Mylia anomala (Hook.) S. Gray 1 – – 0.2 0.8 0.2 0.1 0.2 – – Racomitrium lanuginosum (Hedw.) Brid. 1 – – – 0.3 – 3.0 0.4 0.6 – Sphagnum austinii Sull. 1 – – – – 5.0 0.7 – – –

57  . Concluded

Communitya C1 C2 C3 C4 C5 C6 C7 C8 C9 Number of plots 3 5 5 11 5 9 14 9 5 Species name Stratumb

Bryophytes Sphagnum compactum DC. 1 – – – – – 0.1 0.4 0.7 – Sphagnum lindbergii Schimp. 1 – – – – – – 0.3 2.8 – Scapania undulata (L.) Dum. 1 – – – – – – – 0.3 –

Lichens Cladina portentosa ssp. paciﬁca (Ahti) Ahti 1 – – 1.0 2.5 2.0 3.2 1.7 0.8 – Siphula ceratites (Wahlenb.) Fr. 1 – – – – – – 2.4 – – a C1 = Western hemlock – Sitka spruce – Lanky moss (CWHvh2/04–productive forest); C2 = Western redcedar – Western hemlock – Salal (CWHvh2/01–scrub forest); C3 = Yellow-cedar – Western redcedar – Goldthread (CWHvh2/11–bog forest); C4 = Shore pine – Yellow-cedar – Sphagnum (CWHvh2/12–bog woodland). C5–C9 are sub-communities in the Sphagnum open peatland (CWHvh2/32): C5 = Sphagnum austinii hummock; C6 = Racomitrium lanuginosum hummock; C7 = Rhynchospora alba – Sphagnum tenellum lawn; C8 = Carex utriculata – Sphagnum lindbergii depression; and C9 = Menyanthes trifoliata pool. b Numbers in the stratum column denote the stratum in which the species are categorized: 1 = bryophyte/lichen stratum; 2 = herb stratum; 3 = dwarf shrub stratum; 4 = low shrub stratum; 5 = shrub stratum; 6 = tall shrub stratum; 7 = tree stratum; 8 = tall tree stratum; and 9 = very tall tree stratum. c Values are means of categories of abundance within each community type. Only species whose values are greater than 0.2 in any community are listed.

Menyanthes trifoliata pool + 1.0 Carex utriculata – Sphagnum lindbergii depression CONMN PHMD Rhynchospora alba – Sphagnum tenellum lawn

Racomitrium lanuginosum hummock

Sphagnum austinii hummock

Shore pine – Yellow-cedar – Sphagnum woodland

Yellow-cedar – Western redcedar – Goldthread forest SLOPE Western redcedar – Western hemlock – Salal forest

Western hemlock – Sitka spruce – Lanky moss forest

GWTMN 2 CONMX S I X

A Enviromental variables abbreviated as follows: CONMN – conductivity, minimum level of fluctuation

OC10 CONMX – conductivity, maximum level of fluctuation GWTMN – groundwater table, minimum level of fluctuation GWTMX – groundwater table, maximum level of fluctuation PHMD – pH, median level of fluctuation GWT MX SLOPE – slope OC10 – soil organic matter content at 10 cm 1.0 – below ground surface – 1.0 AXIS 1 +1.0

 . Canonical correspondence analysis of Diana Lake study plots. TWINSPAN (Two-Way INdicator SPecies ANalysis) communities (described in Table 4.2) are superimposed (adapted from Asada et al., 2003b).

58  . Vegetation classiﬁed at the Port Simpson study site by Two-Way INdicator SPecies ANalysis (TWINSPAN) (adapted from Asada et al., 2004)

Communitya (# of plots) P1 P2 P3 P4 Species (18) (76) (156) (27) Shrubs and seedlings Vaccinium alaskaense Howell 0.3b – 0.2 – Menziesia ferruginea Sm. 0.2 1.2 1.4 – Gaultheria shallon Pursh 0.1 0.6 1.8 0.4 Tsuga heterophylla (Raf.) Sarg. – 0.4 0.2 – Vaccinium ovalifolium Sm. – 0.3 0.3 – Thuja plicata Donn ex D. Don – – 0.2 0.1

Herbs Lysichiton americanus Hult. & St. John 0.4 0.1 0.1 0.4 Maianthemum dilatatum (A. Wood) Nels. & J. F. Macbr. 0.3 0.5 2.6 0.1 Cornus canadensis L. 0.1 0.7 2.9 0.1 Rubus pedatus J.E. Sm. – 0.3 0.4 0.1 Linnaea borealis L. – 0.1 2.0 – Dryopteris expansa (K.B. Presl) Fraser-Jenkins & Jermy – 0.1 0.2 – Coptis aspleniifolia Salisb. – – 0.6 – Blechnum spicant (L.) Roth – – 0.5 – Schoenoplectus tabernaemontani (K. C. Gmel.) Palla – – – 0.2

Bryophytes Sphagnum angustifolium (C. Jens. ex Russ.) C. Jens. 2.6 0.1 0.2 0.2 Polytrichum formosum Hedw. 1.5 2.8 0.5 0.4 Dicranum fuscescens Turn. var. fuscescens 1.4 0.3 0.1 – Sphagnum palustre L. 0.8 0.2 0.0 – Sphagnum tenerum Sull. & Lesq. 0.5 0.0 – – Sphagnum rubellum Wils. 0.4 0.3 0.3 0.1 Sphagnum girgensohnii Russ. 0.2 1.3 0.6 0.3 Polytrichum juniperinum Hedw. 0.2 0.1 0.2 – Cephalozia bicuspidata (L.) Dum. ssp. bicuspidata 0.1 0.5 0.1 – Dicranella heteromalla (Hedw.) Schimp. 0.1 1.1 0.6 – Plagiothecium undulatum (Hedw.) Schimp. 0.1 0.3 0.5 – Scapania bolanderi Aust. 0.1 0.8 1.1 – Rhytidiadelphus loreus (Hedw.) Warnst. 0.1 0.7 1.8 – Hylocomium splendens (Hedw.) Schimp. 0.1 0.4 2.5 – Sphagnum pacificum Flatb. – 0.6 0.3 4.9 Pogonatum dentatum (Brid.) Brid. – 0.3 – – Lophozia cf. wenzelii (Nees) Steph. var. wenzelii – 0.3 0.1 – Sphagnum capillifolium (Ehrh.) Hedw. – 0.1 0.6 – Pleurozium schreberi (Brid.) Mitt. – – 0.2 – Barbilophozia floerkei (Web. & Mohr) Loeske var. floerkei – – 0.2 – Dicranum scoparium Hedw. – – 0.3 – Calypogeja muelleriana (Schiffn.) K.Müll. ssp. muelleriana – – 0.3 – a P1: Sphagnum angustifolium community; P2: Polytrichum formosum – Sphagnum girgensohnii community; P3: Cornus canadensis – Hylocomium splendens community; and P4: Sphagnum pacificum community. b Values are means of categories of abundance within each community defined by pseudospecies cut levels of TWINSPAN. Values are rounded to 0.1, and only species whose values are greater than 0.1 in any community are listed.

59 (Turunen and Turunen 2003) showed that Sphagnum rubiginosum, and the one of these areas had undergone palud- taxonomically closely related species, ification relatively recently, which helps to Sphagnum girgensohnii, commonly inhabit confirm the pioneering capacity of S. forested areas and occur at both the Port pacificum and S. angustifolium in natural Simpson and Diana Lake sites. At Port systems, as well. Simpson, however, these species were The multivariate ordination analysis of more abundant in the mounded the relationship between environmental portion of the harvested area than in variables and plant communities showed the unmounded portion. The presence that the distribution of these communities of pools in the mounded area is likely correlated best with water table depth; responsible for the persistence of these pH, conductivity, and slope showed up as species, which are often associated with secondary factors. This indicates that the the pits formed by blowdowns in the for- plants respond mainly to soil moisture est (Noble et al. 1984). In addition, S. and related conditions. Pools formed by pacificum and S. angustifolium, which the mounding, possibly in combination are closely related to known pioneering with a post-harvest rise in water table, species such as S. fallax (Grosvernier et al. appear to provide habitat conditions that 1997; Buttler et al. 1998), likely colonized allow colonization by these species (Figure the hollows created by the mounding 4.3). The acidifying ability of sphagnum process after harvesting. Mounding as a likely creates water chemistry gradients site preparation treatment appears, there- (i.e., pH and conductivity); these gradi- fore, to facilitate the persistence or colo- ents, in turn, facilitate additional sphag- nization of several sphagnum species. num growth and limit the potential for vascular plant establishment and growth (van Breeman 1995).

 . Depressions created by mounding at Port Simpson ﬁlled in with sphagnum moss after 6 years.

60 4.3.3 Moss growth and climate parame- schreberi. These growth threshold temper- ters Figures 4.4 and 4.5 illustrate the atures are preliminary, however, because growth patterns of Pleurozium schreberi of difficulties in obtaining winter growth and four of the sphagnum species studied measurements. See Asada et al. (2003a) for in relation to climatic parameters. For the more detail on the estimation methods for sphagnums, the hollow and the wet lawn temperature thresholds. species (i.e., S. lindbergii and S. pacificum) At Diana Lake, Sphagnum pacificum grew more than the hummock-forming was the fastest-growing species (i.e., verti- species (i.e., S. austinii and S. fuscum) cal stem growth), with an estimated (Figure 4.5); however, the growth rates of growth of 52 mm between May and the hummock-forming species were less November 1999 (Table 4.1); S. lindbergii variable than the hollow and the wet lawn also had rapid stem growth of 43 mm dur- species. Hummock species grew even during the same period. S. austinii had the ing the dry period, albeit slowly, but the slowest growth rate, which was estimated hollow and lawn species did not. at 10 mm. S. fuscum, S. rubellum, and S. Generally, the growth pattern of tenellum showed similar growth rates of Racomitrium lanuginosum, P. schreberi about 15 mm. (these two species showed very similar The most productive sphagnum species growth patterns), and the seven sphag- (total annual biomass) were the hum- num species reflected the precipitation mock-forming S. fuscum and S. austinii pattern rather than that of temperature (Table 4.1). Although the vertical growth (Figures 4.4 and 4.5). Correlation of the hummock species was small, their coefficients between precipitation and dense growth form contributed to this growth were higher than those between high productivity. In particular, the bulk temperature and growth for all species density of S. austinii was the highest (Table 4.1), and five species showed among the species studied. Lindholm and statistically significant correlations. Vasander (1990) showed the same trend The climatic index showed a much for S. fuscum. The next highest productiv- higher correlation with growth than ity values were observed in S. lindbergii either precipitation or temperature alone and S. pacificum. The high vertical growth for all species except S. rubellum (Figures of both species contributed considerably 4.4 and 4.5; Table 4.1). Growth was to this productivity, as they had the lowest significantly correlated with the climatic bulk density among the species studied. index for all of the species except The productivity of S. rubellum was close S. austinii. to that of S. pacificum, but this depended When the lowest temperature above more on bulk density than on vertical which vegetative growth occurs is used as growth. The vertical growth and bulk den- the exploratory temperature threshold in sity of S. papillosum were relatively low, the index, the climatic index should have resulting in low overall productivity. the highest correlation with moss growth. Although S. tenellum had the highest Correlation coefficients for the growth number of capitula, or compact heads of of R. lanuginosum and P. schreberi were individual Sphagnum plants, this species highest with the climatic index when daily had the lowest productivity per area mean temperature was set at 5°C, which among the species studied because of its implies that this is the temperature low bulk density (Table 4.1). The annual threshold for the growth of these two stem growth of P. schreberi was about species. For the sphagnum species, the 22 mm/yr compared to about 9 mm/yr for highest correlation with the climatic index R. lanuginosum (Table 4.1); however, the was at 0°C for most species, 5°C lower annual production of R. lanuginosum was than that for R. lanuginosum and P. higher than that of P. schreberi because of

61 (a) Pleurozium schreberi (n = 30) 0.25

0.20

0.15

0.10

0.05

0.00

16 (b) Precipitation 25 Maximum temperature 14 Minimum temperature 20 12 Mean temperature C) 10 ° 15 8

6 10 Temperature ( Temperature

Precipitation (mm/d)4 Growth rate (mm/d) 5 2

0 0

100 (c) 90 80 70 60 50 40

Climatic index 30 20 10 0 – – – 26 29 15 17 – – – – July 1 – June 30 July 30 July 2 June 6 July 16 August 12 August 27 November 18 August 13 June 18 November 19

 . Growth patterns of Pleurozium schreberi in relation to climatic parameters for eight consecutive sampling intervals from June 1999 to July 2000: (a) mean daily growth (±1 SE); (b) mean daily precipitation, and daily maximum, minimum, and mean temperatures; (c) mean daily climatic index (when temperature = daily mean, and temperature threshold, x = 7) (adapted from Asada et al., 2003a, see reference for the mathematical formula for climatic index).

62 (a) S. austinii (n = 20) 0.2 0.0

(b) S. fuscum (n = 32) 0.2 0.0

Growth rate (mm/d) (d) S. lindbergii (n = 20) 1.0 0.8 0.6 0.4 0.2 0.0

Precipitation 22 18 (e) Maximum temperature Minimum temperature 20 16 Mean temperature 18 14 16 C 12 14 ° 10 12 10 8 8

6 Temperature 6

Precipitation (mm/d) 4 4 2 2 0

200 (f) 150

100

50 Climatic index

0 – – 26 29 15 17 – – – – July 1 June 6 – – July 30 July 2 June 7 August 12 July 16 August 27 November 18 August 13 June 18 May 21

 . Growth patterns of four Sphagnum species in relation to climatic parameters for eight consecutive sampling intervals, May–November 1999: (a)–(d): mean daily growth (±1 SE) of sphagnum; (e) mean daily precipitation, and daily maximum, minimum, and mean temperatures; (f) mean daily climatic index (when temperature = daily mean, and temperature threshold x = 0) (adapted from Asada et al., 2003a, see reference for the mathematical formula for climatic index).

63 its denser growth form. Based on the 1998 comparison of measurements of the most widely measured species, Sphagnum fuscum, the productivity of sphagnum mosses tended towards the top of the range of similar measurements made in other sphagnum-dominated peatlands in Canada (Asada 2002). When the maximum growth rates of three common sphagnum species at the Port Simpson and Diana Lake sites were compared, S. rubiginosum showed considerably higher growth rates in the cutover area (85 mm/yr vs. 55 mm/yr) than in the natural area; the other two species had similar growth rates at both areas. This 0 20 cm Bare ground indicates that the conditions in the Sphagnum girgensohnii mounded cutblock may enhance the 1999 growth rate of S. rubiginosum. The area and volume covered by mosses, especially sphagnum, expanded considerably in 1 year, particularly at the two wetter locations (Figure 4.6), while at the driest location the changes were not nearly as great. This shows that moisture is important in moss colonization and that mosses are actively colonizing more area. Total ecosystem productivity among the five open peatland communities was highest on the Sphagnum austinii hummocks and lowest in the Rhynchospora alba – Sphagnum tenellum lawns (Table 4.4). Moss growth provided the greatest amount of productivity to all communi-  . Change in cover of Sphagnum ties except the Menyanthes trifoliata pool. girgensohnii between 1998 and The total net primary productivity () 1999 at one of the three Port for the bog was not high because the bog Simpson sites (adapted from Asada was dominated by the low productivity et al., 2004). Rhynchospora alba – Sphagnum tenellum lawns. Peatlands with a different plant community composition (e.g., one domi- site, decomposition was fastest in the nated by Sphagnum austinii hummocks) Sphagnum austinii hummocks and Carex would likely have a much higher . utriculata – Sphagnum lindbergii depres- The rate of mass loss was not statisti- sions and slowest in Menyanthes trifoliata cally different among the communities at pools in the open peatland (Asada et al. the Port Simpson site, ranging from 15.7 2004). Most of the mass loss occurred in to 17.7% (Table 4.5). The mass loss rates at the first year, a result which is in agree- the Port Simpson site were not signifi- ment with other studies. When mass loss cantly different from any communities at was examined in relation to the water the Diana Lake site. At the Diana table, decomposition was significantly

64 a  . Estimated total net primary production (NPP; g/m2 per year) for the ﬁve representative micro-communities in the open bog at the Diana Lake study site (adapted from Asada, 2002)

b Above ground Below ground NPP Total NPP Range of c NPP Minimum Maximum Minimum Maximum A/B ratio Menyanthes trifoliata pool 104.7 ± 23.5a 85.5 ± 18.6a 164.6 ± 40.0ab 190.2 ± 41.5ab 269.3 ± 62.8ab 1.2–0.6 Carex utriculata – Sphagnum 300.9 ± 32.4b 121.5 ± 38.8a 194.6 ± 41.5ab 422.5 ± 63.8ac 495.6 ± 51.8c 2.5–1.5 lindbergii depression Rhynchospora alba – Sphagnum 163.6 ± 23.6a 15.1 ± 2.9b 71.6 ± 13.9a 178.7 ± 25.2b 235.2 ± 32.9b 10.8–2.3 tenellum lawn Racomitrium lanuginosum 291.3 ± 30.5b 43.9 ± 5.0a 164.7 ± 19.2b 335.2 ± 30.4ac 456.1 ± 35.4ac 6.6–1.8 hummock Sphagnum austinii 402.4 ± 14.5b 24.1 ± 9.1ab 91.8 ± 34.6ab 426.5 ± 23.5c 494.2 ± 48.9ac 16.7–4.4 hummock a Values are means ± standard error. Means followed by a different letter are significantly different (p < 0.05). b A fixed ratio of (below ground ) / (Total ) = 0.5 was applied to estimate below ground  for Menyanthes trifoliata and 0.88 for Carex utriculata. For other vascular plants, the estimated below ground  includes only fine roots, with some range was considered. For the Menyanthes trifoliata pool, the Carex utriculata – Sphagnum lindbergii depression and the Rhynchospora alba – Sphagnum tenellum lawn, the ratio of 0.33 was used for the lowest estimation, and 0.70 for the highest estimation. For the Racomitrium lanuginosum hummock and the Sphagnum austinii hummock, the ratio of 0.38 was used for the lowest estimation, and 0.70 for the highest estimation. c Ratio of above- and below-ground NPP.

 . Mass loss (decomposition) of Sphagnum fuscum litter from litter bags incubated at 10 cm below ground surface for 1 year (adapted from Asada et al., 2004)

Study site Site seriesa Communityb Mass loss(%)c Port Simpson –d P1 17.4 ± 2.3ab (6) – P2 16.0 ± 1.1ab (20) – P3 17.7 ± 0.6ab (14) – P4 15.7 ± 1.2ab (6) Diana Lake 04 D1 16.5 ± 1.1ab (6) 01 D2 12.9 ± 1.3b (10) 11 D3 16.2 ± 1.2ab (9) 12 D4 16.5 ± 1.3ab (13) 32 D5 23.7 ± 0.9a (3) 32 D6 14.4 ± 1.5b (12) 32 D7 17.1 ± 0.6ab (6) 32 D8 21.0 ± 0.3ab (4) 32 D9 13.5 ± 0.4ab (2) a Site series 32: Non-forested slope – blanket bog; site series; 12: Shore pine – yellow cedar – Sphagnum; site series; 11: Western redcedar – yellow cedar – Goldthread; site series; 01: Western redcedar – Western hemlock – Salal; and site series 04: Western hemlock – Sitka spruce – Lanky moss. b P1 = Sphagnum angustifolium community; P2 = Polytrichum formosum – Sphagnum girgensohnii community; P3 = Cornus canadensis – Hylocomium splendens community; P4 = Sphagnum pacificum community. D1–D5 are micro-communities in the non-forested slope–blanket bog site series and D6–D9 are communities at site series level. D1 = Menyanthes trifoliata pool; D2 = Carex utriculata–Sphagnum lindbergii depression; D3 = Rhynchospora alba – Sphagnum tenellum lawn; D4 = Racomitrium lanuginosum hummock; and D5 = Sphagnum austinii hummock. c Values are means ± standard error; number of plots appears in parenthesis. Means followed by a different letter are significantly different (p < 0.05). d Mainly dominated by 01 before clearcutting and mounding.

65 greater in the aerobic zone above the conditions in the recent past (Turunen water table than in the anaerobic zone and Turunen 2003; Asada and Warner below the water table, with intermediate 2005). decomposition rates in the zone of water Researchers concluded from the studies table ﬂuctuation (Asada and Warner at Diana Lake that hypermaritime peat- 2005). The rate of mass loss was slightly lands rank lower than other continental higher in this study than in comparable peatlands in overall  and carbon accu- studies in other areas. mulation. Although some hypermaritime The long-term peat accumulation rate peatland microcommunities (e.g., S. fus- on the peatland is likely lower than in cum and S. austinii hummocks) have rela- continental peatlands. From a series tively high  and peat accumulation of C14-dated peat cores, Turunen and rates, others (e.g., Rhynchospora alba – Turunen (2003) found that the average S. tenellum lawns) are low in productivity. vertical peat accumulation rate (over the Relatively high decomposition rates in past ± 8000 years) at Diana Lake was hypermaritime peatlands tend to offset 0.15 mm/yr, with a range of 0.09–0.24 production, even in the most productive mm/yr. This accumulation rate is lower sphagnum communities, thus yielding rel- than that found in other studies in conti- atively low overall rates of peat and car- nental North America, which ranged bon accumulation (Malmer and Wallen from 0.39 to 1.05 mm/yr, as well as south- 1993; Asada and Warner 2005). Near sur- east Alaska, which ranged from 0.18 to face peat carbon balance studies indicate 1.05 mm/yr (Gorham et al. 2003). that both the S. austinii and R. alba – S. Recent peat accumulation rates at the tenellum communities are carbon sinks, Diana Lake bogs, measured using 210Pb although the carbon balance in the less- techniques, are 1.4–3.2 mm/yr over the productive R. alba – S. tenellum commu- past 65–70 years and 0.9–1.9 mm/yr over nities could be close to equilibrium the past 200 years, indicating that carbon (Asada and Warner 2005). has accumulated under normal climate

4.4 Vegetation The vegetation of the Diana Lake area is potential to paludify portions of adjacent Types and their characteristic of that on the north coast; upland sites. Dynamics: similar plant communities are described The sphagnum moss species examined Discussion within the Biogeoclimatic Ecosystem had different growth responses to climatic Classiﬁcation () system (Banner et al. variation, mostly related to their habitat 1993). The driving environmental factor in and growth form. Species that form hum- determining these communities is mois- mocks had lower linear growth rates and ture. This is exempliﬁed in the study area less seasonal variation in growth, than by the importance of drainage and water species that grew in wetter conditions, table depth. For example, the mounding such as lawns and hollows. Differences in treatment at the Port Simpson site altered moisture regime between hummocks and the moisture regime in the mounded area hollows may explain these differences. through the formation of pits adjacent Because hollows are wet most of the year, to most mounds. These pits (many had species in this habitat type can use water standing water) were subsequently invad- more easily and therefore undergo less ed by sphagnum mosses that were not stress than hummock-forming species. present or less common in the area before During dry periods when the water level harvesting occurred. These mosses are still drops, however, species in hollows cannot expanding in extent and may have the retain water for growth because of their

66 loose growth form. Conversely, hum- harvesting at Port Simpson, sphagnum mock-forming species, with their denser moss growth has progressed as follows: growth form, can retain water even in dry • Clearcutting alone has not yet promot- periods because of their superior water- ed significant colonization or advance- holding capacity. The moisture content in ment of sphagnum. hummocks, therefore, is lower but more • Mounding after clearcutting created hol- constant than that in hollows. This allows lows in which pools formed or where hummock-forming species to grow during the water table was very shallow. dry periods as well as during wetter peri- • The exposed peat provided a competi- ods, although the growth rate would be tion-free substrate for pioneer sphag- slow. These differences in growth pattern num moss species to invade. between hummock-forming and hollow • The water chemistry gradient set up by or lawn-forming species agree with some sphagnum along the mound–hollow previous findings (Moore 1989; Gerdol transition may further facilitate sphag- 1995). num moss growth and discourage the Even if adequate moisture is present, growth of other plant species. substantial growth will not occur if the Paludification at this site is evident by: temperature is too low. This hypothesis • The presence of S. pacificum and S. was supported by higher correlations angustifolium, which were presumably between growth and the climatic index almost absent before harvesting. These than precipitation alone for most of the species are increasing in area and vol- species studied (Table 4.1). Previous stud- ume, especially in the hollows. They are ies have observed this relationship for thought of as pioneer species, which only a few species. For example, Lindholm later provide conditions appropriate for (1990) determined that the minimum the establishment of other sphagnum temperature for growth of Sphagnum species. fuscum was 0°C; above this temperature, • The rapid expansion of S. girgensohnii growth was controlled by water availabili- patches that presumably help to create ty. Gerdol (1996) observed the same trend lawns on which other bog sphagnum for S. magellanicum. Vitt (1989) confir- species (e.g., S. capillifolium) can es- med the importance of precipitation tablish. above temperature thresholds with the • The vertical growth rate of sphagnum finding that yearly growth variation of at the Port Simpson site is about the Racomitrium microcarpon was related to same or faster than that at the Diana precipitation during the growing season. Lake site. Sphagnum species and the other two • The decomposition rates at the Port moss species exhibit different temperature Simpson site are similar to, or slightly thresholds for growth. Our preliminary slower than, those at the Diana Lake results on the relationship between moss site. growth and the climatic index indicate We are not clear how paludification that the temperature threshold for sphag- will proceed at the Port Simpson site in num growth is about 0°C; for R. lanugi- relation to forest regeneration; we will nosum and P. schreberi, it is about 5°C. continue site monitoring indefinitely. These low thresholds suggest potential Three developmental pathways are possi- winter growth, especially for sphagnum, ble for these sites: in this mild hypermaritime region. Winter 1. Tree regeneration doesn’t proceed well, growth appears considerable, as is evident sphagnum continues to expand, and for sphagnum in other hyperoceanic species composition changes through regions (Hulme and Blyth 1982). succession with expansion of fen or Over the 8 years following forest bog communities in the cutover area.

67 2. Tree regeneration proceeds moderately 3. Regeneration proceeds well on the well on the mounds; because of shad- mounds and, because of increasing ing the expansion of bog-type sphag- interception and evapotranspiration, num stops and shade-tolerant the water table drops. Sphagnum forest-type sphagnum becomes domi- species are unable to persist or expand, nant. The area becomes a wet lower- and an upland forest results with high- productivity forest (similar to er tree productivity than the pre- pre-harvest condition). harvest stand.

4.5 Soil Ecology 4.5.1 Soil/bedrock relationships Mineral biotite. It is a relatively hard rock that soils on the north coast are typically collu- weathers slowly, and the mineral soils vial or saprolitic in origin, most often derived from it are generally shallow developing in shallow veneers over and nutrient poor. Gneissic diorite is an bedrock. The most common bedrock igneous intrusive rock with less quartz types on the north and central coast are: and more biotite, garnet, and some horn- • granodiorite (including quartz diorite blende. Gneissic diorite is slightly banded, and diorite), or foliated, suggesting that partial meta- • gneissic diorite, and morphism has taken place. In this case, • schist or gneiss, with some localized the layering results from additional pres- areas of limestone (Figure 4.7). sure, temperature, or chemical reactions These bedrock types have differences in applied to the rock. Gneissic diorite is weathering rates and mineral composition scattered throughout the CWHvh2 (Table 4.6) resulting in a range of physical (Figure 2.1) and data suggest that this rock and chemical soil properties. Granodiorite type is associated with slightly more pro- is an igneous intrusive rock with a high ductive sites compared with the granodi- content of quartz, feldspar, and some orites. Schist is a strongly foliated, or

 . Four common bedrock types found on the north and central coast of British Columbia.

68  . Total chemical concentrations for bedrock typesa (adapted from Kranabetter and Banner, 2000)

PSCaMgKMoCuFeMnZnCo Bedrock type (g/kg) (g/kg) (g/kg) (g/kg) (g/kg) (mg/kg) (mg/kg) (g/kg) (g/kg) (mg/kg) (mg/kg) Granodiorite 1.07 0.33 29.5 14.8 33.8 < 2 4.8 37.1 0.7 50.2 5.3 (0.3) (0.2) (4.4) (3.7) (11.8) (0.75) (7.5) (0.1) (5.3) (1.39) Gneissic diorite 2.12 2.51 48.8 24.6 23.8 < 2 30.8 63.0 1.1 100.5 10.2 (0.2) (2.4) (6.8) (7.1) (6.9) (23.5) (13.6) (0.2) (37.9) (2.95) Schist 2.15 0.45 87.6 33.9 11.8 3.7 18.3 84.2 1.0 42.0 9.7 (0.2) (0.2) (40.1) (7.2) (2.3) (2.5) (7.3) (26.1) (0.4) (10.0) (4.16) Limestone 0.20 2.83 520.6 9.4 0.4 < 2 < 1 2.6 0.2 8.7 < 1 (0.1) (0.1) (15) (3.8) (0.2) (1.3) (0.1) (2.6) a Values in parentheses are standard errors.

layered, metamorphic rock, intermediate not reached in the soil pit; in these cases, between slate and gneiss with a high con- the measured mineral soil depth will par- tent of mica or mica-like minerals. This tially depend on the thickness of the over- rock type is relatively soft and weathers lying organic layer. quickly to create mineral soil and provide Tables 4.7 and 4.8 summarize soil nutrients for plant growth. As a result, depth related to site series and bedrock some of the highest forest productivity on type. Table 4.7 illustrates the trends in the outer coast is associated with schist mineral and organic soil depth among site bedrock, especially when it occurs in com- series; organic horizon depth tends to bination with limestone. Limestone is increase and mineral soil depth tends largely made up of calcium carbonate; in to decrease from the productive upland the CWHvh2, it is limited to small pockets forests (CWHvh2/04) to the bog forests scattered along the coast. Limestone (CWHvh2/11). These trends were generally weathers by solution and gives rise to not statistically significant (p < 0.05), generally rich, productive forests (e.g., except for the thinner organic horizon CWHvh2/05, Western redcedar – Sitka depth on the CWHvh2/04 sites series spruce – Swordfern), and often unique compared with the CWHvh2/01 and /11. plant communities (Kranabetter and Within both the CWHvh2/01 and /04 site Banner 2000). series, a trend exists in mineral soil depth We examined the relationship between as it relates to bedrock geology, with the bedrock type and mineral and organic soil deepest mineral soils occurring on the depth using information from the Prince metamorphic (schist) bedrock (Table 4.8). Rupert Forest Region ecological database, Again, the data are highly variable and which includes 165 ecosystem plots this trend was not statistically significant. collected from sites throughout the A trend in organic soil depth with CWHvh2. These plots were collected over bedrock type within site series was less the last 25 years to develop an ecosystem apparent, indicating slightly shallower classification, and thus were not specific- organic horizons on metamorphic rock ally designed to determine relationships within the CWHvh2/04 site series only. between bedrock and soil. Soil horizon The nutrient differences between soils thicknesses were combined for both the derived from the various rock types are organic and mineral layers to arrive at the largely due to varying amounts of phos- total depth for each of these soil layers. phorus (P), sulphur (S), magnesium (Mg), The depth of mineral soil must be inter- and potassium (K) (Table 4.9) (Kranabetter preted carefully, however, because in and Banner 2000). For example, schist- nearly one-half of the plots bedrock was derived mineral soils are higher in P, S,

69  . Mean organic and mineral soil depths for CWHvh2 site series on the north and central coastal of British Columbia

Site series n Organic soil depth (cm)a n Mineral soil depth (cm)a 11 29 37.0a (3.5) 24 22.5a (4.6) 01 60 31.7a (2.5) 57 30.9a (3.0) 04 76 20.4b (2.2) 76 36.8a (2.6) a Values in parentheses are standard errors. Means followed by a different letter are significantly different (p < 0.05).

 . Mean organic and mineral soil depths for CWHvh2/01 and CWHvh2/04 site series by bedrock type on the north and central coast of British Columbia

Site series Bedrock type n Organic soil depth (cm)a n Mineral soil depth (cm)a 01 Granitic 37 34.3 (3.7) 34 24.9 (3.7) Gneissic diorite 15 23.1 (5.9) 15 41.4 (5.6) Schist 7 35.1 (8.6) 7 37.6 (8.2) 04 Granitic 35 21.4 (2.3) 35 37.2 (4.1) Gneissic diorite 25 19.7 (2.8) 25 32.0 (4.9) Schist 14 17.9 (3.7) 14 45.4 (6.5) a Values in parentheses are standard errors. Means within a site series were not significantly different (p < 0.05).

 . Average chemical properties of mineral soils (0–20 cm), well-drained sites only a (adapted from Kranabetter and Banner, 2000)

Bedrock-derived Total N Total P Total S C:N C:P C:S Min.-N Avail. P Exch. Ca Exch. K Exch. Mg pH soil (g/kg) (g/kg) (g/kg) ratio ratio ratio (mg/kg) (mg/kg) (cmol/kg) (cmol/kg) (cmol/kg) (H2O) Granodiorite 1.8 0.23 0.22 29.1 220a 284a 14.6a 5.49 0.67 0.049a 0.19a 4.47 (0.3) (0.21) (0.05) (1.1) (14.9) (21.4) (1.6) (0.7) (0.06) (0.006) (0.02) (0.03) Gneissic diorite 2.4 0.35 0.34 26.6 169ab 195ab 18.9a 8.78 0.70 0.050a 0.22a 4.49 (0.8) (0.83) (0.18) (1.5) (13.6) (11.7) (3.0) (2.6) (0.14) (0.008) (0.04) (0.05) Schist 2.3 0.41 0.33 23.6 134b 170b 45.0b 8.79 1.64 0.109b 0.49b 4.64 (0.3) (0.47) (0.04) (1.0) (9.8) (12.0) (7.1) (1.6) (0.26) (0.010) (0.04) (0.10) a n = 3 for each bedrock type. Values in parentheses are standard errors. Values followed by a different letter are significantly different (p < 0.05).

Mg, and K than mineral soils derived coast has significant implications for for- from other bedrock types. These nutrients est productivity. Glacial till is typically on their own can influence site productiv- composed of a mixture of ground up ity, but they can also lead to higher nitro- rocks of varied mineralogy. It has high gen (N) availability (measured as surface area, and good potential for root mineralizable N), a nutrient fundamental access, balanced nutrient content, and to plant growth. At the other end of the weatherability. Soils derived from bedrock spectrum, soils derived from granodiorite that has weathered in situ, such as those are low in nutrient elements, while soils on the north coast, are generally less bal- from gneissic diorite tend to be interme- anced in their nutrient content and limit- diate between schist and granodiorite. ed by the specific chemical and physical The scarcity of glacial till on the north properties of the rock.

70 Where roots have access to rock sur- These disturbance events tend to mix faces, recent studies have demonstrated mineral and organic soil layers, slowing the capacity for root and mycorrhizae the buildup of surface organic material, exudates such as organic acids to weather and improving nutrient availability rocks and take up nutrients directly (Bormann et al. 1995). In contrast, the (Jongmans et al. 1997; Bormann et al. lower-productivity western redcedar- 1998). Root and mycorrhizae access may dominated sites (CWHvh2/01 and /11) be extremely limited, however, on hard found on the gentle terrain of the Hecate plutonic rocks because of the lack of frac- Lowlands are imperfectly to poorly tures and low surface area. Where deep, drained, and have much lower levels of wet organic horizons develop, they can available nutrients (Kranabetter et al. also prevent access to the underlying 2003). These sites lack disturbances, which weathered bedrock. On the more easily allows deep layers of organic matter to weathered and fractured metamorphic accumulate. If disturbance events are rare rock, root access is much better, but com- or small, deep accumulations of surface pared with glacial till, even this relatively organic matter result. On these sites, the nutrient-rich bedrock is less balanced and depth of the organic layers prevents tree more subject to single nutrient deficien- roots from gaining access to mineral cies. These rocks have already undergone soil. In some cases, mineral horizons are significant weathering, which has removed absent (Folisols) and forest floors play an many of the most weatherable minerals. increasingly important role in nutrient The implications to forest management supply (Chapter 2, section 2.3). of this lack of glacial till on the north coast are significant, especially because 4.5.3 Organic matter and nutrient avail- it is the harder, resistant, and relatively ability Edmonds et al. (1989) suggested nutrient-poor plutonic rocks that domi- that nutrient availability from forest floors nate the coast. Low rates of nutrient depends on the turnover rate and nutrient inputs to these systems via slow weather- content of the organic matter. These fac- ing and atmospheric deposition (rain, tors are examined in two HyP3 soil stud- clouds, fog) mean that longer rotations ies. Kranabetter and Banner (2000) will be required to re-establish mer- compared chemical properties and lab chantable forests in these areas, and fertil- microbial respiration rates (as an indica- ization treatments may also be necessary. tor of decomposition rates) in forest floor Initial results from the HyP3 studies sug- samples collected from productive, freely gest that the inherent forest productivity, drained forest sites occurring on contrast- as well as the potential to improve pro- ing bedrock types (granodiorite, gneissic ductivity through site treatments, is con- diorite, schist, and limestone). siderably higher in the areas dominated Kranabetter (B.C. Ministry of Forests by metamorphic bedrock. 2004, unpublished data) compared the same forest floor properties among 4.5.2 Soil disturbance and nutrient avail- CWHvh2/01, /04, and /11 site series, and ability Though bedrock plays a then manipulated water content of forest significant part in determining nutrient floor samples to see whether moisture availability and site productivity, distur- content influenced decomposition rates bance history also plays a role. On the (measured as microbial respiration in the north coast, high forest productivity is lab). generally associated with sites on steep Although organic matter turnover rates slopes with good soil drainage and aera- were expected to be higher on the richer tion, and often a history of natural distur- bedrock types, on the more productive bance by landslide or windthrow events. site series, and in the least-saturated forest

71 floors, this was not apparent in the lab content of partially decomposed organic respiration results. Microbial respiration matter (the end product of decomposi- was variable in the incubated forest floor tion) than lower decomposition rates. samples taken from the top 15 cm of soil These laboratory respiration experi- profiles, but broadly similar on freely ments do not completely mimic field drained sites across contrasting bedrock processes, however. The CWHvh2/01 and types (Figure 4.8a). Across site series /11 site series could experience periods of either at field moisture content, or at complete saturation and reduced decom- higher or lower moisture levels, no statis- position compared to well-drained sites, tically significant trends were evident especially at depths deeper than 15 cm, as (Figure 4.9). Surprisingly, some samples measured in this study. The tests conduct- representing the wettest forest floors from ed in this experiment were limited to car-

the poorest site series had the highest res- bon cycling (CO2 release). It is possible piration rates. that the wetter soil conditions could lead Lower C:N and C:P ratios on the richer to differences in faunal and microbial schist-derived soils (Figure 4.8b), and on activity that affect N rather than C miner- the most productive site series in both alization and this may result in differences old-growth and second-growth conditions in organic matter “quality.” The P content (Figure 4.10), suggest that organic matter of litter and soil has been reported to quality is better characterized by nutrient control N mineralization in upland and content than by turnover rates. The organic soils (Purchase 1974; Munevar and results imply that the decline in tree pro- Wollum 1977; Pastor et al. 1984; White ductivity across site series more strongly and Reddy 2000; Carlyle and Nambiar reﬂects a decline in the available nutrient 2001), and is generally recognized as

700 (a) 80 (b) C:N C:P 600

60 500

400

(ppm) 40 2 300 CO Carbon ratios

200 20

100

0 0 Granite Gneiss Schist Limestone Granite Gneiss Schist Limestone

Bedrock type Bedrock type

 . Comparisons of microbial respiration rates and chemical properties: (a) a comparison of forest ﬂoor (0–10 cm) respiration rates (laboratory incubation) across well-drained bedrock-derived soils (3 samples per bedrock type); (b) C:N and C:P ratios of upper forest ﬂoors across well-drained, bedrock-derived soils (adapted from Kranabetter and Banner, 2000).

72 1200 (a) 800 (b) 04 400% 01 700 600% 1000 11 800% 600 800 500 per gram per gram

2 600 2 400

300

ppm CO 400 ppm CO

200 200 100

0 0 Gneiss 1 Gneiss 2 Schist Granite 04 01 11 Transect Site series

 . Comparisons of microbial respiration rates and moisture content: (a) forest floor respiration rates (laboratory incubation) across site series at the appropriate field moisture content (400% for the 04, 600% for the 01, and 800% for the 11); (b) forest floor respiration (laboratory incubation) across moisture contents for the CWHvh2/04, /01, and /11 site series.

120 (a) 100 (b)

100 80

80 60 60 40 Carbon ratios Carbon ratios 40

20 20 C:P x10 C:P x10 C:N C:N 0 0 04 01 11 07 04–06 01

Site series Site series

 . Changes in C:N and C:P ratios across CWHvh2 site series in (a) old-growth and (b) second-growth stands. Site series numbers as per Figure 2.7.

73 exerting a large influence on N cycling retranslocation between current and and fixation (Chapin et al. 1978; Cole and older foliage was also examined. This use- Heil 1981; Vitousek and Howarth 1991). ful method is based on the theory that Low supplies of P, due to lower-quality trees on nutrient-poor sites will retranslo- parent materials or reduced rooting in cate, or move, nutrients from older foliage mineral soils beneath deep surface organic to younger foliage to compensate for layers, may limit N availability and this deficiencies in available soil nutrients may in turn result in a decline in forest (Nambiar and Fife 1991). productivity. Ecosystem decline resulting Foliar chemistry, rather than soil chem- from the long-term absence of catastroph- istry, was used to ascertain nutrient avail- ic disturbance has been linked to P limita- ability on these sites because studies show tions in a recent study of contrasting that soil chemistry is of limited value in chronosequences in tropical, temperate, determining nutrient availability. Soil and boreal zones (Wardle et al. 2004). analysis measures the supply of elements Early results from operational trials potentially available, whereas foliar analy- suggest that long-term improvements in sis provides an index of the amount actu- tree productivity require mixing of organ- ally taken up by the trees (Ballard and ic matter with mineral soil horizons to Carter 1986). In addition, soil analysis is improve soil aeration and to increase the often difficult to interpret when forest soil uptake and cycling of P, N and S. This depth and composition are extremely treatment is thought to mimic the variable, as is often the case on the outer beneficial consequences of natural distur- coast of British Columbia. bances, such as colluvial mixing or blow- Many foliar nutrient concentrations down events, which are associated with (e.g., N, P, K, S) had a positive relation- sites that support more productive stands ship with leader increment. As leader in these coastal forests (Kranabetter and increment continued to increase, these Banner 2000). nutrients did not appear to “plateau” at Mixing and mounding site treatments the adequate concentrations previously are being tested at operational trials at the determined in greenhouse growth tests by Port Simpson and Oona River study areas Ballard and Carter (1986) (Figures 4.11, (Chapter 6, sections 6.2 and 6.3). 4.12, and 4.13). Some foliar cation concentrations (e.g., Ca, Mg) showed little rela- 4.5.4 Tree growth and foliar nutrition tionship to growth. Trees on the better Tree growth and nutrition in second- growing sites (well-drained schist soils growth plantations (approximately and seepage sites; CWHvh2/04, /05, /06, 20 years of age) were compared across a and /07 site series) in this study exhibit range of sites (e.g., CWHvh2/ 01, /04, /05, the highest productivity that has been /06, /07, and /11 site series) occurring over found in the hypermaritime zone. Typical various bedrock types from granodiorite foliar nutrient concentrations for each to schist (Kranabetter et al. 2003). Foliar tree species from these more productive analysis was used to infer which nutrient sites (Table 4.10) were compared with elements were at adequate levels and published reports of adequate foliar nutri- which limited growth (van den Driessche ents. Western hemlock and Sitka spruce 1974; Ballard and Carter 1986; Walker and had nearly adequate concentrations of N Gessel 1991). To examine relationships (1.45–2.2%) and P (0.25–0.35%) on pro- between foliar nutrition and growth, foliar ductive sites (Radwan and Harrington analysis was carried out on sample trees 1986; Weetman et al. 1989a, 1989b; Walker from which height and increment meas- and Gessel 1991). In general, the cations urements were taken. To assess plant and micronutrients on productive sites response to nutrient limitations, nutrient were also at adequate concentrations, as

74 80 Current-year needles 80 1-year-old needles 70 70

60 60

50 50

40 40

30 30 Height increment (cm) Height increment (cm) 20 20

10 10

0 0 0 5 10 15 20 0.0 2.0 4.0 6.0 Foliar N concentration (g/kg) Foliar Ca concentration (g/kg)

80 80

70 70

60 60

50 50

40 40

30 30 Height increment (cm)

20 Height increment (cm) 20

10 10

0 0 0.0 1.0 2.0 3.0 4.0 0 5 10 15 Foliar P concentration (g/kg) Foliar K concentration (g/kg)

80 80

70 70

60 60

50 50

40 40

30 30 Height increment (cm) Height increment (cm) 20 20

10 10

0 0 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 2.0 2.5 Foliar S concentration (g/kg) Foliar Mg concentration (g/kg)

 . Western hemlock nutrient concentrations for current-year needles and 1-year-old needles across height increment (adapted from Kranabetter et al., 2003).

75 80 Current-year needles 80 1-year-old needles 70 70

60 60

50 50

40 40

30 30 Height increment (cm) Height increment (cm) 20 20

10 10

0 0 0 5 10 15 20 25 0 5 10 15 Foliar N concentration (g/kg) Foliar Ca concentration (g/kg)

80 80

70 70

60 60

50 50

40 40

30 30 Height increment (cm) Height increment (cm) 20 20

10 10

0 0 0.0 0.5 1.0 1.5 2.0 2.5 0 5 10 15 Foliar P concentration (g/kg) Foliar K concentration (g/kg)

80 80

70 70

60 60

50 50

40 40

30 30 Height increment (cm) Height increment (cm) 20 20

10 10

0 0 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 Foliar S concentration (g/kg) Foliar Mg concentration (g/kg)

 . Sitka spruce foliar nutrient concentrations for current-year needles and 1-year-old needles across height increment (adapted from Kranabetter et al., 2003).

76 40 Current-year needles 40 1-year-old needles 35 35

30 30

25 25

20 20

15 15 Height increment (cm) Height increment (cm) 10 10

5 5

0 0 0 5 10 15 20 25 0 5 10 15 Foliar N concentration (g/kg) Foliar Ca concentration (g/kg)

40 40

30 30

20 20

15 Height increment (cm) 10 Height increment (cm) 10

0 0 0.0 1.0 2.0 3.0 4.0 0 5 10 15 Foliar P concentration (g/kg) Foliar K concentration (g/kg)

40 40

35 35

30 30

25 25

20 20

15 15

Height increment (cm) 10 Height increment (cm) 10

5 5

0 0 0.0 0.5 1.0 1.5 0.0 0.5 1.0 1.5 2.0 Foliar S concentration (g/kg) Foliar Mg concentration (g/kg)

 . Western redcedar foliar nutrient concentrations for current-year needles and older needles across height increment (adapted from Kranabetter et al., 2003).

77  . Foliar nutrient concentrations for western hemlock, Sitka spruce, and western redcedar on productive sites of north coast British Columbia (adapted from Kranabetter et al., 2003)

NP SMgKCaB CuFeMoMnZn Species (%) (ppm) Western hemlock 1.45 0.28 0.12 0.120 0.90 0.25 15 3.0 35 0.02 1500 12 Sitka spruce 1.55 0.22 0.11 0.085 0.90 0.40 10 3.0 30 0.02 1000 25 Western redcedar 1.85 0.28 0.11 0.150 0.90 0.65 15 5.0 30 0.20 250 20

reported by Ballard and Carter (1986). The 4.13). The slightly higher rate of S accu- largest discrepancy between observed and mulation for western hemlock was the adequate nutrient levels occurred with P only difference in nutrient concentrations in western redcedar (0.28% P compared between new and older foliage that sug- to the suggested level of 0.16%). According gested a larger deficiency on poorer sites. to published standards, levels as high as On richer sites (CWHvh2/05 and /07 sites 0.28% P occur more often in interior red- series), where N availability might be nat- cedar (Radwan and Harrington 1986). urally quite high, the large decrease in S Such a large variation from the expected P and Mg concentrations in older needles concentration implies that the suggested suggested Sitka spruce was limited by level of 0.16% may underestimate the true these elements. This is similar to the P requirements for western redcedar on induced deficiencies that can sometimes these sites. occur when N fertilizer is applied All three tree species had strong posi- (Brockley et al. 1992). Western hemlock tive correlations between average leader also showed similar patterns of possible increment and foliar N, P, and S, along Mg retranslocation on seepage sites. with secondary correlations for many Overall, the observed patterns of retrans- cations or micronutrients. The generally location are opposite from the pattern positive, linear response of many foliar originally expected. Rather than finding macro- and micronutrients made it greater retranslocation on nutrient-poor difficult to infer specific growth limita- sites as a response to stress, greater move- tions. It is unclear, for example, whether ment of nutrients between old and new the availability of N, P, S, K, Mg, Cu, Fe, foliage was recorded on richer sites. These Mn, and Zn in soils changed across mois- preliminary findings raise new questions ture and bedrock regimes, or whether the concerning nutrient limitations to growth, deficiencies of N or P simply limited the especially on richer sites; further field tests uptake of these other elements. The strong with added nutrients would be needed to correlations between micronutrients such draw more complete conclusions. as Fe and Zn and leader increment were Although vegetation competition or often species specific, an aspect that would edaphic conditions posed no apparent be interesting to test further in field trials. difficulties in establishing trees on the Retranslocation between new and older CWHvh2/01 sites studied, the height foliage was determined by comparing increment results show considerable dif- nutrient concentrations of current needles ferences in growth rates from well-drained against the previous year. The largest dif- to imperfectly drained sites. Increment ference in foliar nutrient concentrations growth on the CWHvh2/01 sites averaged generally occurred in more productive 42% less for western hemlock, 56% less trees; nutrient concentrations on the most for Sitka spruce, and 32% less for western stressed sites showed generally more sta- redcedar compared with the better- bility between years (Figures 4.11, 4.12, and drained sites. Bedrock also had an

78 influence on growth increment. The sites. The autecological characteristics of CWHvh2/01 sites on granodiorite and western hemlock are intermediate between gneissic diorite bedrock showed the lowest those of western redcedar and Sitka growth rates (Table 4.11), suggesting that spruce. This species, therefore, could be these sites are at the lowest threshold of considered an acceptable or preferred operability. The CWHvh2/01 schist sites, species on CWHvh2/01 sites, depending however, had more acceptable rates of tree on specific management objectives and growth, and are thus considered to have other factors (e.g., mistletoe risk). See higher potential for forestry operations. Chapter 5 (section 5.3 and Table 5.1) for a The height increment results for west- summary of tree species productivity in ern redcedar, Sitka spruce, and western the CWHvh2, and Chapter 7 for a further hemlock illustrate some important aspects discussion of species selection guidelines. of the autecology of these species. Western The growth and foliar responses redcedar, although relatively slow grow- observed largely confirm the lower pro- ing, had the smallest decrease in height ductivity of the CWHvh2/01 site series, increment across the site series, and thus especially on poorer bedrock types, and seems better adapted to the poorer soils provided further evidence that N and P over the long term. Considering ecological availability declines along the productivity suitability as well as species value, western gradient. Operational trials are under way redcedar should be chosen as the preferred at Port Simpson and Oona River to test species on most CWHvh2/01 sites. Sitka whether the availability of N and other spruce exhibited by far the best growth on nutrients is enhanced by mixing mineral the good sites, but showed dramatically soil with forest floors, which simulates reduced growth on the poor sites, espe- blowdown events, or through additions of cially on granodiorite. Species selection P fertilizer (see Chapter 6). The growth guidelines reflect the higher nutrient and and nutrition results from these current soil drainage demands of this species studies should allow us to better evaluate (Banner et al. 1993), and thus spruce is the the potential, and investment required, to least acceptable tree species on CWHvh2/01 improve site productivity on CWHvh2/01

 . Average height increment (cm) for each tree species by soil moisture regime and bedrock typea (adapted from Kranabetter et al., 2003)

Bedrock type Site series Granodiorite Gneissic Schist Western hemlock 01 CwHwb Salal 14.0 (1.6) 5.6 (0.9) 38.0 (5.2) 04–06 Site Seriesc 26.6 (4.6) 15.5 (1.8) 57.4 (3.8) 07 CwSsb-Devil’s club 37.1 (5.4) 17.6 (1.9) 58.4 (5.6) Sitka spruce 01 CwHw Salal 5.8 (1.0) 9.1 (1.4) 21.7 (2.2) 04–06 Site Series 14.0 (2.0) 21.3 (2.6) 49.1 (2.0) 07 CwSs-Devil’s club 52.4 (5.0) 26.8 (3.6) 51.4 (4.1) Western redcedar 01 CwHw Salal 15.0 (1.8) 13.2 (1.2) 23.6 (1.5) 04–06 Site Series 21.4 (1.8) 26.1 (2.3) 28.5 (2.0) 07 CwSs-Devil’s club 26.3 (2.7) 25.8 (2.4) 31.1 (1.5) a n = 3 per combination. Values in parentheses are standard errors. b Cw = western redcedar, Hw = western hemlock, Ss = Sitka spruce. c See Figure 2.7 for site series names.

79 sites. Although the lowest-productivity rock. Metamorphic (schist) sites have the sites on poorer bedrock may initially seem greatest potential for improving nutrient to have a greater need for productivity- availability through soil-mixing treat- improving site treatments, fertilization ments because mineral soils are often (rather than soil mixing) may be the only much deeper and higher in nutrient option on these sites because very little cation content. Although our existing mineral soil is associated with the harder operational trials are both located on igneous rocks; the soils are most often metamorphic bedrock, we plan to estab- Folisols, which consist of deep  (forest lish trials on poorer bedrock types to bet- floor horizons) layers with a thin layer ter deﬁne operability limits. (less than 10 cm) of mineral soil over

4.6 Model of From the studies of ecosystem patterns, ecosystem development to some degree in Ecosystem processes, and productivity outlined most other terrestrial environments, their Development and above, a simple model of ecosystem devel- inﬂuence is especially dramatic in the Productivity in opment in the CWHvh2 has emerged CWHvh2. This model relates directly to the CWHvh2 (Figure 4.14). In this model, three main the edatopic grid typically used to portray factors operate in combination to drive  site series (Figure 2.7); soil moisture ecosystem development and productivity and nutrient regime (and thus site series) in this hypermaritime environment: are largely determined by the interaction 1. bedrock geology of bedrock geology, soil drainage, and dis- 2. soil drainage turbance history. 3. disturbance history The scarcity of glacial till in this coastal Although these same factors inﬂuence environment highlights the importance of

Rapid Rapid hic

Productive Drainage Drainage Metamorphic MetamorpHigh Forests Biomass Forest Bedrock Bedrock Productivity Trees vs. Mosses Poor Poor Medium Allocation eous productivity Blanket Bogs Medium Low Forests and Bog Forests Igneous Ign Dynamic Stable Dynamic Stable Disturbance Disturbance

 . Simpliﬁed model of ecosystem development and forest productivity in the CWHvh2. The version on the left emphasizes the role of bedrock geology, soil drainage, and disturbance history in controlling tree productivity; the version on the right emphasizes how these same environmental factors determine the relative allocation of tree versus moss biomass in north-coast ecosystems.

80 bedrock geology. Most soils develop nutrient availability is relatively low directly from the weathering of bedrock because of the wet, acidic conditions and or colluvial material. This contrasts with low rates of nitrogen mineralization. many other areas where a mantle of gla- Better-drained sites that often have a his- cial till of mixed lithology masks the tory of natural disturbance, especially influence of bedrock. In addition, sharp where soil organic and mineral horizons contrasts in bedrock type occur on the are mixed, exhibit higher forest product- outer coast, from the hard, slowly weath- ivity. ering granodiorites with relatively low Although models are inherently sim- amounts of available nutrient elements, to plistic, on the majority of sites on the the much softer, faster weathering meta- outer coast, ecosystem development and morphic rocks and limestone with more forest productivity can be explained by nutrient-rich lithologies. These different the above three factors working in combi- bedrock types manifest themselves in dra- nation. The model presented in Figure matic differences in plant communities 4.14 can also be used to guide forest man- and forest productivity. agement investments and activities, and to Excess soil water is the rule in this help define and understand the limits of hypermaritime environment, and subtle operability in the CWHvh2. For example, variations in slope or internal soil drain- marginally productive sites occurring on age result in significant differences in metamorphic rock will likely exhibit high- forest productivity. In contrast to the er second-growth productivity following majority of other subzones in the province harvesting and site treatments, compared (where moisture deficits are common), with a similar site on granodiorite the most freely drained sites in the bedrock. CWHvh2 are the most productive sites for Note that two variations of the model trees. Even these “drier” sites are fresh to are presented—one emphasizing forest moist in absolute terms, but as long as soil productivity and one emphasizing bio- water is dynamic rather than stagnant, mass allocation. As indicated by the soil then tree productivity will remain moder- ecology, moss productivity, and succes- ate to high. sion studies, a switch in biomass alloca- The tendency for organic matter to tion from trees to mosses (and other accumulate on sites that have not been understorey vegetation) occurs as sites disturbed by windthrow, landslides, or progress along the (slow) trajectory of fluvial disturbances for hundreds (or organic matter accumulation and declin- thousands) of years is also dramatic in the ing tree productivity. Bogs and bog forests CWHvh2. As soil organic matter accumu- are often referred to as “low productivity.” lates, soils become wetter and tree roots They are, however, highly productive if become more confined to surface organic one considers the annual rates of total horizons. Although the nutrient capital biomass accumulation measured in these in these organic horizons is considerable, ecosystems (see section 4.3.3).

81 5 CLASSIFICATION AND INVENTORY

5.1 Introduction The classification and inventory compo- establish baseline growth patterns and and Approach nent of the HyP3 Project serves as the link rates for these sites, we combined the lim- between the hydrology and ecosystem ited site index and “years to breast height” process components, and the application sampling data available for second-growth of results across the north coast. The proj- stands with stem analysis of trees in old- ect has used the Biogeoclimatic Ecosystem growth stands. Classification () system (Pojar et al. At each of the HyP3 study sites, timber 1987) as the framework to make ecologi- cruising was carried out to quantify stand cally based forest management recom- structure, species composition, and gross mendations.  uses the site series to and merchantable volume. Several forest classify forests for management purposes. mensuration attributes are summarized Ecosystem classification is invaluable for from these data for each of the CWHvh2 choosing appropriate sites for in-depth site series studied. studies, and also for extrapolating the A review of rare, or otherwise threat- results to other similar sites throughout ened or imperiled ecosystems of the the north coast. CWHvh2 is presented to examine any We conducted sampling in old-growth potential impacts on these ecosystems and second-growth forests to collect base- that might result from expanding forestry line information on tree growth and site operations into the lower-productivity productivity throughout the range of forest types. forested site series in the CWHvh2. Forest A predictive ecosystem mapping () harvesting in the CWHvh2 has largely model was developed for the outer coast. been limited to the higher-productivity The resulting maps identify the site series forest types. For these sites, we have most likely associated with each forest regeneration and site index data from sec- cover polygon. These maps help to estab- ond-growth and old-growth forests, which lish the extent and location of potentially provide information on regeneration and operable low-productivity cedar–hemlock productivity under full-light and partial- forest types. Site series productivity data light conditions. On the lower-productivi- can also be combined with these maps to ty sites (CWHvh2/01, /11, and /12), few aid in growth and yield analysis for the second-growth stands exist; therefore, to .

5.2 Site Series The  system classiﬁes sites within each the necessary comparisons between forest Description subzone into a range of site series depend- productivity and soil moisture–nutrient ing on relative soil moisture and relative relationships, study transects include soil nutrient regimes (see Figure 2.7). other common site series within the Within the CWHvh2, the HyP3 Project is CWHvh2. mostly concerned with lower-productivity Depending on the soil development forests with mesic and wetter moisture and the site series, three phases of site regimes, and medium to poor nutrient series are recognized in this subzone regimes on the edatopic grid; the site (Banner et al. 1993). series representing these forest types are: 1. Mineral phase: occurs on sites with col- CWHvh2/01 (Western Redcedar – luvial, morainal, weathered bedrock, or Western Hemlock – Salal) and CWHvh2/11 fluvial deposits (> 10 cm). (Western Redcedar – Yellow-cedar – 2. Lithic phase: occurs on sites with an Goldthread) (Banner et al. 1993). To draw organic veneer over thin (< 10 cm)

82 mineral soil over bedrock or boulders. Lowlands. These very open and scrubby 3. Peaty phase: occurs on sites with a “forests” are found on a variety of slope peaty veneer or blanket (> 10 cm) over positions, but mostly on gentle terrain; bedrock. however, on poor bedrock these forests can extend up considerable slopes in some 5.2.1 Zonal forests Zonal forests areas. Soils are organic veneers or blankets (CWHvh2/01; Western redcedar – over bedrock or saprolite. The tree species Western hemlock – Salal) have relatively are usually yellow-cedar and western red- low tree stature, open canopies, and well- cedar with some shore pine interspersed developed shrub layers compared with (Figure 2.4 and Figure 5.2). Forests on the productive forests (see Figure 2.3 and CWHvh2/11 site series are of lower pro- Figure 5.1). These forests are found on a ductivity than those of the CWHvh2/01 range of sites from upper to lower slopes. (Banner et al. 1993). The soils are usually imperfectly drained Podzols and Folisols with relatively deep 5.2.3 Bog woodlands and open bog organic horizons in comparison to the ecosystems Bog woodlands (CWHvh2/12; underlying mineral horizons. The open Shore pine – Yellow-cedar – Sphagnum) scrubby forests are dominated by western and open bogs (CWHvh2/32; slope–blan- redcedar, yellow-cedar, and western hem- ket bog) are very common on the outer lock, with shore pine and mountain hem- coast (Figures 2.5 and 2.6; Figures 5.3 and lock abundant in some locations. Forests 5.4). These woodland and bog complexes on the CWHvh2/01 site series often have are typical of the subdued terrain of the low productivity compared to zonal sites Hecate Lowlands where organic soils pre- found in other CWH subzones (Banner dominate. A sparse tree cover of less than et al. 1993).

5.2.2 Bog forests Bog forests (CWHvh2/11; Western redcedar – Yellow- cedar – Goldthread) are very extensive in the CWHvh2, especially on the Hecate

 . Zonal forest (CWHvh2/01), Oona River.  . Bog forest (CWHvh2/11), Diana Lake.

83  . Bog woodland (CWHvh2/12), Diana Lake.  . Open bog (CWHvh2/32), Diana Lake.

10% is typical of the woodlands; scattered, spruce – Devil’s club) site series. These very scrubby trees occur in the open bogs. forests are most commonly located on The main tree species is shore pine, with steep colluvial slopes, but are also found some yellow-cedar and western redcedar on inactive coarse fluvium with free (Banner et al. 1993). Based on detailed drainage, toe slope seepage sites, deep vegetation sampling, Asada (2003b) iden- morainal soils, and shallow Folisols. tified five sub-communites within the CWHvh2/05 is restricted, almost exclu- CWHvh2/32 open bogs (see section 4.3.2). sively, to areas of metamorphic or limestone bedrock. Depending on disturbance 5.2.4 Productive forests Productive non- history and chance, varying mixtures of floodplain forests are represented by the western hemlock, western redcedar, Sitka CWHvh2/04 (Western hemlock – Sitka spruce, and amabilis fir dominate these spruce – Lanky moss), CWHvh2/05 sites (Figure 2.2 and Figure 5.5). Compared (Western redcedar – Sitka spruce – with zonal sites, these site series occur on Swordfern), CWHvh2/06 (Western red- better-drained or more nutrient-rich soils, cedar – Sitka spruce – Foamflower), and which results in higher-productivity CWHvh2/07 (Western redcedar – Sitka forests (Banner et al. 1993).

84  . Productive upland forest (CWHvh2/06), Port Edward.

5.2.5 Floodplain forests Productive forests found on floodplains are site series CWHvh2/08 (Sitka spruce – Lily-of-the- valley), CWHvh2/09 (Sitka spruce – Trisetum), and CWHvh2/10 (Red alder – Lily-of-the-valley) (Figure 5.6). The three different site series are distinguished by the height and frequency of flooding of the high, middle, and low benches, respectively. The low benches (CWHvh2/10) have Regosolic soils, with a progression to Brunisolic and Podzolic soils occurring on the less frequently flooded middle and high benches (CWHvh2/09 and /08). Sitka spruce, western hemlock, and western redcedar dominate the CWHvh2/08 site series; the CWHvh2/09 site series is dominated by Sitka spruce, while the CWHvh2/10 site series is dominated by red alder (Banner et al. 1993).

5.2.6 Swamp forests Swamp forests (CWHvh2/13; Western redcedar – Sitka  . Productive spruce stand on a spruce – Skunk cabbage) are found in CWHvh2/08 site, Barnard Creek, poorly drained areas with mineral seepage. Princess Royal Island.

85 These forests are localized in lower slope cedar – Salal) are uncommon, but do positions and level areas sometimes over occur on some upper-slope and ridge- ﬂuvial deposits, with organic blankets and crest positions on Folisols over (mostly veneers. The mineral seepage results in a nutrient-poor) bedrock. Species composi- richer nutrient regime and better forest tion, stand structure, and productivity are productivity than in the bog forests and all very similar to the CWHvh2/01 site bog woodlands (CWHvh2/11 and /12), series (Western redcedar – Western which have a similar moisture regime. Hemlock – Salal). On the most exposed, These forests are most often dominated by dry rocky knolls and outcrops, the Shore western redcedar, less commonly by Sitka pine – Yellow-cedar – Racomitrium spruce, with a vigorous and consistent (CWHvh2/02; Figure 5.8) site series cover of skunk cabbage characterizing the occurs. These shrubby, open habitats with understorey (Figure 5.7) (Banner et al. very thin soils typically occur on rock out- 1993). crops interspersed throughout open bogs on the Hecate Lowlands (Banner et al. 5.2.7 Drier forest and scrub Drier forests 1993). (CWHvh2/03; Western redcedar – Yellow-

5.3 Site In British Columbia, the vast majority of at a breast height age of 50 years. The pro- Productivity forest land is covered with old-growth ductivity of a site largely determines how stands (“old” depends on the zone). The quickly trees grow and thus volume pro- B.C. Forest Service used data derived from duction and merchantable rotation age. In inventory plots located in old stands to recent years, extensive site index sampling establish a baseline measure of site quality of second-growth stands (< 120 years, or productivity, commonly referred to as Figure 5.9) indicates that site productivity “site index.” Site index () is an estimate estimates from the old-growth forest of potential tree height growth on a site cover inventory underestimate actual site over a ﬁxed period of time. In British productivity of regenerated stands (Table  Columbia, we use 50, or total tree height 5.1). Second-growth forests tend to grow

 . Swamp forest (CWHvh2/13), Diana Lake.  . Dry, windswept rock outcrop (CWHvh2/02), McCauley Island.

86 faster than projected by the inventory- based site index estimates derived from old-growth stands (Nigh 1998; Nussbaum 1998; Olivotto and Meidinger 2001). Tree growth and thus site index is strongly influenced by ecological site factors such as soil moisture and nutrient regime. A significant relationship exists between site index and  site series. The Site Index–Biogeoclimatic Ecosystem Classification Project () produced a database that summarizes site index estimates (from second-growth field data) by site series for coniferous tree species in British Columbia (B.C. Ministry of Forests 2003). These data are collected from second-growth stands in which trees have regenerated under open conditions, and therefore the resulting site index estimates are believed to better represent growth potential on these sites following a disturbance. On a sample of five map sheets from the north coast, for example,  . Second-growth CWHvh2 stand used current forest cover information shows for site index sampling, Khyex River. that more than 50% of the total land base  has a 50 of eight or less. Estimates of productivity for the same area using Table 5.1 summarize data collected over a  estimates puts just 4% of the land large area of the north coast in the last base into this category (Olivotto and 10 years. The data include information Meidinger 2001; see section 5.6 for a fur- obtained from old-growth stem analysis ther discussion of ecosystem-based pro- plots from four locations, second-growth ductivity and yield analysis). Although foliar nutrient plots from 14 locations, other factors will also determine operabil- and  plots from 50 locations. These ity, many areas on the north coast cur- data show that estimates of site productiv- rently listed as inoperable may indeed be ity from old-growth stands significantly more productive than currently estimated underestimate second-growth site poten- by the forest inventory and therefore have tial (e.g., western redcedar old growth, some potential for sustainable forestry. CWHvh2/01 site series;  = 3.9 vs.  50 second-growth 50 = 17.8; old-growth 5.3.1 Site Index and Years to Breast years to breast height () = 50 vs. sec- Height The site index values presented in ond-growth years to  = 7).

87  . Old-growth and second-growth productivity dataa for the CWHvh2, north coast of British Columbia. Site series numbers as per Figure 2.7 (see section 5.2 for site series descriptions).

Old Growth, Mean Site Indexb Western Mountain Western Site series Amabilis fir redcedar hemlock hemlock Shore pine Sitka spruce Yellow-cedar 01 3.9 3.0 2.7 4.8 4.7 4.0 (1.9–10.5) (2.0–7.7) (1.3–6.2) (2.3–9.5) (2.5–5.7) (1.7–9.8) 04 2.9 5.2 3.2 (1.7–5.0) (2.8–7.4) (1.7–5.3) 11 2.9 3.1 3.1 3.8 2.9 (2.0–4.5) (2.3–3.9) (1.4–5.3) (1.8–7.1) (1.7–5.5) 12 3.3 3.0 2.0 2.8 2.4 (2.5–4.5) (2.2–5.5) (1.9–2.1) (1.8–3.7) (1.7–3.5) Old Growth, Mean Years to Breast Heightb Western Mountain Western Site series Amabilis fir redcedar hemlock hemlock Shore pine Sitka spruce Yellow-cedar 01 58 50 69 65 59 67 45 (21–120) (15–124) (24–105) (9–173) (17–84) (27–89) (11–137) 04 70 37 61 34 (12–163) (21–50) (6–158) (34–34) 11 73 72 73 51 73 (32–137) (37–105) (40–159) (31–70) (32–158) 12 79 101 108 89 107 (37–184) (38–178) (63–172) (39–174) (45–361) Second Growth, Mean Site Indexc Western Mountain Western Site series Amabilis fir redcedar hemlock hemlock Shore pine Sitka spruce Yellow-cedar 01 17.8 18.0 16.6 (13.5–22.3) (8.0–31.0) (13.5–21.0) 04 26.9 22.7 22.9 27.4 (14.9–35.4) (17.0–34.3) (10.0–33.5) (19.5–40.8) 05 31.7 28.3 (24.7–36.0) (24.4–32.8) 06 29.6 23.2 27.0 33.0 (18.2–34.7) (18.9–26.6) (21.0–32.8) (23.1–42.4) 07 21.7 21.9 29.3 (15.5–28.0) (11.1–36.2) (18.6–43.1) Second Growth, Mean Years to Breast Heightc Western Mountain Western Site series Amabilis fir redcedar hemlock hemlock Shore pine Sitka spruce Yellow-cedar 01 7 6 5 6 (3–11) (3–10) (3–6) (3–8) 04 7 8 5 5 (5–12) (5–12) (3–9) (4–8) 05 6 5 (5–8) (5–6) 06 6 10 6 6 (5–11) (9–10) (5–7) (4–7) 07 10.0 6 6 (9–11) (4–9) (3–11) a Mean site index data: height (m) at 50 years (breast height age). Range of site index in parentheses. b Values derived from HyP stem analysis plots.  c Values derived from HyP stem analysis samples and BC Forest Service SIBEC plots.

88 5.4 Forest To quantify and compare the volume and Sitka spruce, with some amabilis ﬁr and Mensuration quality of timber across the spectrum of minor amounts of yellow-cedar, dominate site series, timber cruises were done at the CWHvh2/04 site series. Stems per three HyP3 study sites (Diana Lake, Oona hectare by species follow similar trends River, and Smith Island). Results present- to volume, except for the CWHvh2/04, ed in Table 5.2 are shown using a lower where relatively few stems of Sitka spruce limit of both 7.5 and 17.5 cm . Differ- and amabilis ﬁr (these species are mostly ences among the site series are most evi- restricted to the upper canopy layers) dent in volumes and basal area, with the make up the volume for these sites CWHvh2/04 site series having the highest (Figure 5.11). gross and net volume, the most basal area, The stems per hectare by diameter and trees with the largest . The class curves all show a similar and typical CWHvh2/01 and /11 site series are progres- reverse “J” shape (exponential distribu- sively lower for all of these measures. tion), with many small trees and fewer Stems per hectare followed the opposite large trees. The slopes of the curves exhib- pattern with the CWHvh2/01 and /11 site it some differences, however, with the series having higher densities than the CWHvh2/11 and /01 site series showing CWHvh2/04 sites. The number of snags steeper curves as a result of fewer large per hectare above 7.5 cm  was highest trees. Basal area diameter class distribu- on the CWHvh2/11 site series, followed by tions by site series show clear differences the CWHvh2/01 and /04. Above 17.5 cm among sites. Basal area on the CWHvh2/11 , the CWHvh2/04 site series had the site series is concentrated in the smaller most snags followed by the CWHvh2/11 diameter classes, with very little basal area and /01. When compared to zonal sites in above 55 cm diameter (Figure 5.12). On other CWH variants, the CWHvh2/01 site CWHvh2/01 site series, there is little basal series contains the lowest volume per area over the 100 cm diameter classes, and hectare and the highest number of snags on the /04 site series, the curve ends at 110 per hectare (B.C. Ministry of Forests cm. The peaks in basal area in the larger 2001). size classes on the CWHvh2/04 sites are Western redcedar contributes the most produced by a few large trees. volume on the CWHvh2/01 and /11 site The distribution of trees by height class series, with lesser amounts contributed by clearly shows the differences among the western hemlock, yellow-cedar, and shore site series with the CWHvh2/04 including pine (minor amounts of Sitka spruce are more trees in the taller height classes than found in the CWHvh2/01) (Figure 5.10). the CWHvh2/01 and /11 site series (Figure Western hemlock, western redcedar, and 5.13). Merchantable trees on the

 . Summary of average stand characteristics for the CWHvh2/11, /01, and /04 site series at the Diana Lake, Oona River, and Smith Island study site areas

3 a Volume/ha (m ) Basal area/ha Average  Site series n (cm) Gross Net (m2) Stems/ha Snags/ha (cm) 11 21 7.5 188.7 133.4 38.0 787 399 28.7 17.5 159.0 107.6 33.8 459 123 33.8 01 44 7.5 329.3 229.3 54.2 809 202 30.3 17.5 298.4 202.9 50.4 457 107 37.9 04 11 7.5 508.1 398.7 60.6 760 152 35.8 17.5 479.0 373.2 56.6 372 152 44.7 a Diameter at breast height values represent the lower diameter limit used in the cruise compilation. Site series numbers as per Figure 2.7.

89 400 Western redcedar Yellow-cedar Western hemlock Shore pine /ha)

3 300 Sitka spruce Amabilis fir Totals

200

100 Net merchantable volume (m Net merchantable

0 11 01 04 Site series

 . Net merchantable volume per hectare (> 17.5 cm DBH) by site series and species at the Diana Lake, Oona River, and Smith Island study sites. Site series numbers as per Figure 2.7.

500 Western redcedar Yellow-cedar Western hemlock 400 Shore pine Sitka spruce Amabilis fir 300 Totals

200 Stems per hectare

100

0 11 01 04 Site series

 . Stems per hectare (> 17.5 cm DBH) by site series and species at the Diana Lake, Oona River, and Smith Island study sites. Site series numbers as per Figure 2.7.

90 (a) CWHVh2/11

6 250

5 200

ha) 4

2/ 150 3 100 2 Stems per hectare Basal area (m 50 1

0 0 10 25 40 55 70 85 100 115 130 145 200 10 25 40 55 70 85 100 115 130 145 200 Diameter (cm) Diameter (cm)

(b) CWHVh2/01

6 250

5 200

4 /ha) 2 150 3

100 2 Basal area (m Stems per hectare

1 50

0 0 10 25 40 55 70 85 100 115 130 145 200 10 25 40 55 70 85 100 115 130 145 200

Diameter (cm) Diameter (cm)

6 250

5 200

4 /ha)

2 150 3 100 2 Basal area (m Stems per hectrare 1 50

0 0 10 25 40 55 70 85 100 115 130 145 200 10 25 40 55 70 85 100 115 130 145 200 Diameter (cm) Diameter (cm)

 . Basal area and stems per hectare (≥7.5 cm DBH) in diameter classes at the Diana Lake, Oona River, and Smith Island study sites by site series: (a) CWHvh2/11; (b) CWHvh2/01; and (c) CWHvh2/04. Site series numbers as per Figure 2.7.

91 500 All sites 11Sites 01 Sites 400 04 Sites

300

200 Stems per hectare 100

0 1 2a2b3a3b4a4b5 6 Height class

350 CWHvh2/11Sites Western redcedar Yellow-cedar 300 Western hemlock 250 Shore pine Sitka spruce 200

150

100 Stems per hectare 50

0 12a2b3a3b4a4b5 6 Height class

350 CWHvh2/01 Sites Western redcedar Yellow-cedar 300 Western hemlock 250 Shore pine Sitka spruce 200 Amabilis fir

150

100 Stems per hectare

0 1 2a 2b 3a 3b 4a 4b 5 6 Height class

350 CWHvh2/04 Sites Western redcedar Yellow-cedar 300 Western hemlock 250 Sitka spruce Amabilis fir 200

150

100 Stems per hectare

0 12a2b3a3b4a4b5 6 Height class

 . Stems per hectare (≥7.5 cm DBH) in height classes by site series at all sites and by species at the Diana Lake, Oona River, and Smith Island study sites. Site series numbers as per Figure 2.7.

92 CWHvh2/01 and /11 site series are was dominant in all height classes, with concentrated in height class two, while yellow-cedar and shore pine also promi- CWHvh2/04 sites contain many mer- nent in the shorter height classes. A sum- chantable trees in height class three and mary of stand characteristics for all three four. On all sites, there is a significant site series at each site is presented in number of stems less than 7.5 cm  Tables 5.4, 5.5, and 5.6. (e.g., advance regeneration ) not tallied. Species distributions in height classes  . (Table 5.3) vary greatly among site series. Tree heights used for height class The CWHvh2/04 site series are dominated designations by hemlock in all height classes, but hemlock is especially dominant in the shorter Height class Height range (m) height classes because of its high shade 1 0.1–10.4 tolerance and ability to regenerate well on 2a 10.5–14.9 organic substrates. Hemlock also domi- 2b 15.0–19.4 3a 19.5–23.9 nated the shorter height classes in the 3b 24.0–28.4 CWHvh2/01. Western redcedar was more 4a 28.5–32.9 prominent in the taller height classes on 4b 33.0–37.4 the CWHvh2/01 site series. On the 5 37.5–46.4 CWHvh2/11 site series, western redcedar 6 46.5–55.4

 . Summary of average stand characteristics for the CWHvh2/11 (Western redcedar – Yellow- cedar – Goldthread) site series at the three study sites

3 a Volume/ha (m ) Basal area/ha Average  Study site n (cm) Gross Net (m2) Stems/ha Snags/ha (cm) Diana 4 7.5 165.0 120.0 33.3 546 374 27.9 17.5 137.0 97.1 30.2 481 212 29.6 Oona 7 7.5 200.7 135.2 38.9 702 228 29.5 17.5 179.1 116.3 36.0 353 61 38.5 Smith 10 7.5 189.7 137.4 39.4 944 528 28.5 17.5 153.6 105.8 33.8 526 132 32.8 a Diameter at breast height (DBH) values represent the lower diameter limit used in the cruise compilation.

 . Summary of average stand characteristics for the CWHvh2/01 site series (Western redcedar – Western hemlock – Salal) at the three study sites

3 a Volume/ha (m ) Basal area/ha Average  Study site n (cm) Gross Net (m2) Stems/ha Snags/ha (cm) Diana 8 7.5 429.0 288.1 69.8 1532 267 25.9 17.5 375.0 242.3 61.9 618 108 34.7 Oona 22 7.5 331.5 235.0 50.5 574 98 36.1 17.5 309.1 215.6 48.5 412 84.1 41.3 Smith 14 7.5 268.7 186.5 51.0 684 330 29.5 17.5 238.9 161.7 47.4 437 143 36.3 a Diameter at breast height (DBH) values represent the lower diameter limit used in the cruise compilation.

93  . Summary of stand characteristics for the CWHvh2/04 site series (Western hemlock – Sitka spruce – Lanky moss) at the three study sites

3 a Volume/ha (m ) Basal area/ha Average  Study site n (cm) Gross Net (m2) Stems/ha Snags/ha (cm) Diana 2 7.5 592.0 457.4 55.1 189 29 63.3 17.5 586.0 453.0 55.1 189 29 63.3 Oona 4 7.5 453.8 359.3 49.0 438 48 37.9 17.5 429.9 338.7 47.0 361 48 43.5 Smith 5 7.5 517.8 406.7 72.0 1246 621 31.7 17.5 475.3 368.9 64.8 469 271 42.0

a Diameter at breast height (DBH) values represent the lower diameter limit used in the cruise compilation.

3 5.5 Biodiversity As the HyP Project was analyzing the red- and blue-listed ecosystems (Table Considerations potential of harvesting in previously inop- 5.7). These forests fall into two groups: erable forests, the biodiversity implica- 1. inland forests mostly on floodplains, tions of including these forests in the fans, and colluvial slopes; and operable land base were investigated. This 2. forests that occur in salt-spray zones was done at the ecosystem, plant commu- along windward shores or in brackish nity, and species levels. shoreline habitats. Operational implementation of the 5.5.1 Red- and blue-listed ecosystems HyP3 project’s research findings does not, Over 200 rare ecosystems in British for the most part, pose significant or seri- Columbia are listed with the Conservation ous risks to these forest ecosystems. Data Centre () in Victoria. Many of Harvesting activities in the forests targeted these ecosystems are in the “old” structur- by the HyP3 Project, however, could al stage of commercially valuable forests, impinge on rare forest types if: or in mature forest and grassland ecosys- • the stands targeted for harvesting are tems targeted for agricultural and urban accessed via roads built through rare development, especially in the southern forest types; one-third of the province. • the higher-productivity stands repre- A red-listed ecosystem is considered senting red- or blue-listed ecosystems by the  as “imperiled provincially are used to economically justify har- because of extreme rarity or because of vesting of the lower-productivity some factor(s) making it especially vul- cedar–hemlock forests occurring adja- nerable to extirpation or extinction.” A cent to them; or red-listed ecosystem typically has fewer • camp facilities or log-sorting and than 20 high-quality occurrences within booming activities damage the rare for- the province. A blue-listed ecosystem may est types. have from 21 to 100 occurrences, or is considered vulnerable to either large-scale 5.5.2 Other rare or threatened ecosystems disturbance or small-scale, but chronic, Several additional rare, sensitive, human-caused disturbance. Both red- and or threatened ecosystems occur in the blue-listed ecosystems can be either natu- CWHvh2 that are presently not listed with rally rare, or depleted and rare because of the . These ecosystems are either not human activities. listed because of incomplete inventories, Currently, the mainland portion of the or because the -listed ecosystems use Very Wet Hypermaritime Coastal Western  as a framework; many rare ecosys- Hemlock subzone (CWHvh2) contains 11 tems have not been properly classified

94 list ) a Biogeoclimatic Provincial Provincial B.C. Conservation Data Centre, 2004 Lanky moss fluvium coarse inactive Western redcedar – Sitka spruce – spruce – Sitka redcedar Western fernSword Alluvial/colluvial; limestone CWHvh2/05 S2S3 and metamorphics Blue Western redcedar – Sitka spruce – spruce – Sitka redcedar Western forest Alluvial/colluvial CWHvh2/07 S3 Blue Sitka spruce – False lily-of-the-valley – False spruce Sitka floodplain bench High – Trisetum spruce Sitka CWHvh2/08 floodplain bench Middle S2 CWHvh2/09 Red S2 Red Red alder – False lily-of-the-valley alder – False Red - spruce – Sitka redcedar Western floodplain bench Low Skunk cabbage slopes on lower Swamps CWHvh2/10 CWHvh2/13 S3 S3 and depressions Blue Blue Sitka spruce – Kindbergia spruce Sitka – Reedgrass spruce Sitka fern – Sword spruce Sitka zone Spray zone Spray terraces Marine CWHvh2/15 CWHvh2/17 CWHvh2/16 S3 S3 S3 Blue Blue Blue Sitka spruce – Pacific crab apple – Pacific spruce Sitka Estuaries, brackish sloughs CWHvh2/19 S3 Blue – – spruce hemlock – Sitka Western Alluvial/colluvial; CWHvh2/04 S3 Blue Polystichum Oplopanax Lysichitum – – – Maianthemum dilatatum Maianthemum Trisetum canescens Trisetum Kindbergia oregana Kindbergia Calamagrostis nutkaensis munitum Polystichum Malus fusca Malus Picea sitchensis Picea sitchensis – – – – – – Maianthemum dilatatum Maianthemum Picea sitchensis – – Red- and blue-listed ecosystems of the hypermaritime mainland coast British Columbia (adapted from / – Very Wet Hypermaritime 2Wet Very Hypermaritime 2 Wet Very Devil's club Group 1.Group mostly on floodplains forests and alluvium/colluvium Inland – Picea sitchensis heterophylla Tsuga loreus Rhytidiadelphus Thuja plicata munitum Thuja plicata horridus Picea sitchensis Wet Hypermaritime 1Wet Picea sitchensis rubra Alnus Hypermaritime 1 Wet Thuja plicata americanum 2.Group forests / Shoreline Sea-spray Picea sitchensis Picea sitchensis Picea sitchensis  .  Scientific name name Common situation Typical unit site Picea sitchensis rank a Provincial ranks. S1 = critically imperilled; S2 = imperilled; S3 = vulnerable; S4 = apparently secure; and S5 = secure.

95 within the  framework, or they have occurred in many of them. A moderately specific attributes, such as bedrock geolo- productive old-growth forest with good gy, which make them special cases within amounts of both yellow-cedar and west- a given site series. ern redcedar, including veterans, was identified at Stair Creek on Douglas Forested ecosystems Although yellow- Channel in the early 1990s. Ecosystems cedar is common in the CWHvh2, moder- represented included CWHvh2/01, /03, ately productive old-growth stands of /04, /05, and /06. This area was proposed yellow-cedar, with healthy trees of good as an ecological reserve in 1992, and is still form in height class four and five, are rare a valid candidate for protection. (Figure 5.14). They typically occur at mid- Yellow-cedar decline (i.e., the death of elevations (250–400 m) and harvesting mature yellow-cedar trees) over consider- (generally helicopter logging) has able areas of southeast Alaska has been recognized as an ecological and management issue for many years (Hennon and Shaw 1997) Although various factors are implicated, including poor drainage and climate change (linked to early spring freezing injury), the causal agents remain unclear and continue to be studied. Some north coast stands located at 300–400 m elevations have recently been observed to have symptoms of yellow-cedar decline (P. Hennon, U.S. Department of Agri- culture, Juneau, Alaska, pers. comm., Dec. 2004). Forests on postglacial volcanic deposits are another category of regionally rare ecosystem. Strikingly productive forests of western hemlock, amabilis fir, western redcedar, and Sitka spruce occur on volcanic cones at Lake Island and Kitasu Hill (Swindle Island), with deep well-drained soils of ash and other unconsolidated material. Somewhat similar forests occur on deep tephra soils at Crow Lagoon, a caldera near the mouth of Khutzeymateen Inlet, and a sister caldera further upslope. All of these areas have been affected by harvesting. Karst landforms with gentle (but freely drained) topography can support productive forests (Figure 5.15), although limestone bedrock is rare on the north and mid-coast of British Columbia. Karst topography is a unique landscape, with  . Productive yellow-cedar stand on Mount Genevieve, unusual and distinctive physical features Haida Gwaii/Queen Charlotte Islands. and hydrology. The associated ecosystems have highly productive soils, which support

96 • northwest Aristazabal Island (and as yet unspecified areas at Kettle Inlet, Switzer Cove, Turtish Harbour–Borrowman Bay, south of Nob Hill; field assessments of these four areas are required) • east side of Aristazabal Island (area opposite the Ramsbotham Islands has karst, but the limestone deposit was quarried in the past, and recently has been further explored) • Kumealon Inlet (the karst here has been logged over, but more may exist in the vicinity); some impressive second- growth forests occur on limestone in this area. Further field assessment and documen- tation of karst ecosystems are necessary.

Non-forested ecosystems Although the non-forested habitats we describe below should not be directly affected by HyP3 applications, we include them for com- pleteness, and because these ecosystems are rare, sensitive, and play significant roles in regional landscape diversity.  . All seabird islands and marine mam- Productive Sitka spruce– western redcedar forest on limestone mal rookeries and haul-outs are intrinsi- bedrock, Hamner Island. cally unique, and therefore singularly rare (Figure 5.16). Examples include: Lucy populations of specialized invertebrates. Islands; Bonilla Island; North Danger Although the combination of productive Rocks; Mud Island; Prince Leboo Island; old-growth forests (CWHvh2/04, /05, and the Moore, Whitmore, and McKenney /06) on limestone-karst is very rare in the islands of Ecological Reserve 23; the mainland CWHvh2, harvesting has Dewdney and Glide islands of Ecological occurred in stands on limestone because Reserve 25; and the Byers, Conroy, of the relatively high productivity of these Harvey, and Sinnett islands of Ecological stands. Except on karst, productive old Reserve 103. Collectively, these islands are forests seldom occur on gentle topogra- very rare, biologically significant, sensitive phy, which usually supports low-produc- to disturbance, and threatened by oil tivity ecosystems such as the CWHvh2/01, spills, careless recreationists, fishermen, /11, and /12. Karst ecosystems are incom- and introduced species; however, these pletely known in the study area. These seabird and marine mammal islands will rare karst ecosystems may occur in the not be directly affected by HyP3 activities. relatively common site series and thus the All estuaries are unique and are excep- Conservation Data Centre has not iden- tionally biologically productive (Figure tified them as rare. 5.17). Ecologically, estuaries are considered We know of several well-developed “keystone” ecosystems; that is, ecosystems karst ecosystems in the CWHvh2: whose influence on the surrounding • Chapple–Emily Carr inlets on Princess watershed and landscape is disproportion- Royal Island ately large relative to their abundance.

97  . Kerouard Islands, south of Kunghit Island, Haida Gwaii/Queen Charlotte Islands.

 . Tidal estuary, Kwatna Inlet, east of Burke Channel.

98 Estuaries are also very sensitive to marine crabs. These ecosystems typically occur as pollution, excessive harvesting, and sus- narrow shoreline strips or small pockets. ceptible to harvest-related damage from Large expanses of saline tidelands are log booming, roads, and camp facilities. uncommon and have high conservation The two largest and most important values. Notable examples include Big Bay and complex estuaries in the mainland and Kitkatla Inlet (including Billy Bay). CWHvh2 are those of the Skeena and Sandy beaches are another intrinsically Nass rivers. These big estuaries provide rare type of ecosystem along the rocky, habitat for numerous species, such as: often steep, and predominantly low- juvenile salmon, eulachon, crab, bears, energy shoreline of the north coast. Most trumpeter swan, brant, great blue heron, are very small pocket beaches, as on the western grebe, and many other water west side of Digby Island and on Kitson birds, as well as rare plants and plant Island; a few are medium-sized, such as communities on brackish mudflats those on Tugwell Island. Large sand beach- (MacKenzie and Moran 2004). es occur just south of Cape Caution, and Other smaller estuaries in this sub- on the west sides of Calvert (Figure 5.18), zone include the Koeye, Winter Inlet, Campania (McMicking Inlet), and Kumealon Inlet, Lowe Inlet, Barnard Porcher islands. These beaches are valu- Harbour, and Codville Lagoon; the Koeye able, not only because of their spectacular is probably the most significant of the beauty and Crown land status, but also smaller estuaries. Significant estuaries also because the organisms associated with exist in the adjacent CWHvm, including them are sensitive to marine pollution. the Stagoo, Kwinamass, Quottoon, Tombolos on southwest Princess Royal Kitikiata-Quall, Klekane, Khutzeymateen, Island (along Laredo Channel) and Fin Bay of Plenty, Laredo Inlet, and Kwatna. and Bonilla islands are rare landforms and High-salinity tidal marshes, mudflats, sites of special cultural significance. and eel-grass (Zostera marina) beds are Although peatlands are common and also very productive systems, and are extensive on the north coast, nutrient- especially important as habitat for migra- rich, minerotrophic fens and marshes are tory and wintering water birds and for uncommon, and almost never extensive in tidal invertebrates, such as clams and the CWHvh2 (Figure 5.19). Rich sedge fens and marshes mostly occur as narrow fringes along sluggish streams and the margins of lakes.

5.5.3 Rare plant species or habitats Rare plant species occurring in the CWHvh2/01 forests were investigated as part of the HyP3 Project. The focus of ﬁeld investiga- tions was lichens and mosses because of our general lack of knowledge about these plant groups. During harvesting at the Oona River operational trial, lichens and bryophytes were collected from felled trees, and later examined for rare species (Williston 2003b). In addition, the general area of Oona River was assessed for rare species, or species growing on unusual substrates. These collections did not reveal  . Sandy beach on the west side of Calvert Island. any rare or endangered species of

99 of Porcher Island (Williston 2003b). Four species are new to the foliicolous flora of North America, including two lichens, one moss, and one liverwort (Table 5.8). Their presence reflects the distinctively stable, mild, and very humid conditions in coastal rainforests of British Columbia. These forests support a long and favour- able season for the establishment and growth of foliicolous lichens and bryophytes. Though foliicolous species are well known from tropical and subtropical regions, the floristics and ecology of their temperate counterparts have been the subject of only two studies. In 1943,  . Carex sitchensis fen near Prudhomme Lake, Prince Rupert. Daubenmire documented eight foliicolous lichens from northwestern Idaho; 30 years later, Vitt et al. (1973) listed 16 lichens and bryophytes or lichens (Geiser et al. 1994; five bryophytes growing on living western Goward et al. 1994; Ryan 1996; Goward redcedar scale leaves from a few localities 1996; Goward 1999); however, the results in coastal Washington and British Colum- of this limited survey should not suggest bia. Whether the substrate specificity an absence of these species in zonal noted among these organisms is related forests. to nutrient enrichment, pH, or the lack Two species of normally terrestrial of inhibitory compounds is not known. lichens, Cladina portentosa ssp. pacifica The current  list of red- and blue- and Cladina arbuscula ssp. beringiana, listed vascular plants for the North Coast were observed growing as epiphytes on Forest District does not contain any species the boles and lower limbs of shore pine that are normally found in CWHvh2/01 in peatlands of north coastal British forests nor any species that may be Columbia (Williston 2001). These lichens regionally rare or at the limits of their dis- have not been previously reported as tribution, although these species are also demonstrating an epiphytic habit; they not likely to occur on zonal sites (J. Pojar, are likely found as epiphytes in this area Canadian Parks and Wilderness Society, owing to their abundance in adjacent ter- Whitehorse, Yukon; pers. comm., 2003). restrial habitats and the windy, humid maritime climate, which provides suitable 5.5.4 Animal species of conservation con- dispersal and growing conditions (P. cern The investigation of rare animal Williston, Gentian Botanical Research; species in the CWHvh2/01 was done by pers. comm., 2004). consulting local wildlife biologists and Foliicolous lichens and bryophytes (i.e., using the  list of red- and blue-listed those that grow on the leaves [including animal species for the North Coast Forest scales and needles] of vascular plants) District. Three species were identified that are relatively rare in temperate North may be sensitive to increased harvesting in America; they are known only from the the CWHvh2/01 forests: rainforests of the northwest part of the 1. the red-listed northern goshawk continent. Seventeen foliicolous lichens (Accipiter gentilis ssp. laingi); and bryophytes are reported from a single 2. the red-listed marbled murrelet western redcedar growing along the shore (Brachyramphus marmoratus); and

100  . A comparison of foliicolous lichens and bryophytes from Porcher Island and those reported by Vitt et al. (1973) from other coastal localities in British Columbia

Foliicolous Species Porcher Island Vitt et al. (1973) Lichens Candelariella vitellina (Hoffm.) Müll. Arg. + Catillaria bouteillei (Desm.) Zahlbr. + Cavernularia hultenii Degel. + + Cetrelia cetrarioides (Duby) Culb. & C. Culb. + + Tuckermannopsis chlorophylla (Willd.) Hale + + Hypogymnia physodes (L.) Nyl. + + Hypogymnia tubulosa (Schaerer) Hav. + + Hypotrachyna sinuosa (Sm.) Hale + + Lecanora pulicaris (Pers.) Ach. + Lepraria sp. + + Physcia tenella (Scop.) DC. + + Parmelia sulcata Tayl. + + Placynthiella sp. + Platismatia glauca (L.) Culb. & C. Culb. + + Ramalina farinacea (L.) Ach. + + Rinodina sp. + Usnea sp. + + Xanthoria candelaria (L.) Th. Fr. + + Liverworts Frullania franciscana M.A. Howe + Porella cordaeana (Huebener) Moore + Mosses Orthotrichum consimile Mitt. + Orthotrichum lyellii Hook. & Tayl. + Orthotrichum pulchellum Brunt. + Orthotrichum speciosum Nees + Ulota phyllantha Brid. +

3. the blue-listed coastal tailed frog Columbia. Some genetically unique, in- (Ascaphus truei). sular forms of species may also occur on While these species do not depend par- north coast islands; however, little infor- ticularly on CWHvh2/01 forests, they may mation exists about this aspect of the face an additional threat if harvesting rates area’s biodiversity (D. Steventon, B.C. increased on the north coast. Research on Ministry of Forests, Smithers, B.C.; pers. these species is ongoing in coastal British comm., 2004).

5.6 Predictive An ecologically based inventory is re- jurisdictions such as the coastal forest dis- Ecosystem quired to apply results from ecosystem- tricts, however, detailed ﬁeld-based  is Mapping based studies such as those conducted for prohibitively expensive and will not be the HyP3 Project. The terrestrial ecosys- available for the foreseeable future. tem mapping () methods developed Alternatives to  have been developed for British Columbia (Banner et al. 1996) and piloted over the past several years in provide the preferred level of mapping British Columbia and elsewhere. These detail and reliability in the application of approaches use existing inventories, and ecosystem management approaches to known or expected relationships between landscape units. For very large and remote ecosystem units (e.g., site series) and

101 inventory attributes, to predict ecological cover features, slope, aspect, water and map units (Figure 5.20). riparian features, and bedrock type. To Ecologists and geographic information produce the final  maps, knowledge system () specialists at the B.C. tables, which were developed for each of Ministries of Forests and Sustainable the applicable biogeoclimatic units, were Resource Management in Victoria and used to run the  polygon attributes Smithers co-operatively developed a through a knowledge engine (EcoNGen). Predictive Ecosystem Mapping () These first draft maps received a field- approach called “EcoGen” (Meidinger based reliability assessment; subsequent et al. 2000; Figure 5.21). The result of this refinements to the knowledge tables led to initiative is a predictive ecosystem map- map revisions (Jones 2001). These final ping model for the outer coast. To pro- EcoGen maps received another reliability duce predictive ecosystem maps for the assessment that involved polygon checks North Coast , this model established throughout the area, and comparisons relationships between ecosystems and for- between the EcoGen mapping and the est cover, Terrain Resource Inventory detailed  mapping carried out at the Mapping (), digital elevation models Diana Lake and Smith Island intensive () and bedrock geology mapping, study sites (Jones 2001). This reliability within the context of refined biogeocli- assessment indicated that the EcoGen pre- matic subzone mapping. These maps dictive mapping was 67% accurate for the identify the site series most likely associat-  label matching the dominant ecosys- ed with each forest cover polygon and thus tem unit on the ground, and 80% accu- help to establish the extent and location of rate when the adjacent ecosystem unit potentially operable poor- and low-site (i.e., adjacent on the edatopic grid) cedar–hemlock forest types. (Figure 2.7) was deemed acceptable. As part of the HyP3 Project, an EcoGen When the EcoGen initiative started pilot was established near Prince Rupert several years ago, the existing available involving 75 000 ha within five 1:20 000 inventories (forest cover, , bedrock forest cover map sheets. Fieldwork deter- geology) were recognized as significantly mined the relationships between site series limited for use in predicting ecosystems. and inventory attributes, such as forest At that time, a  accuracy of 65–70%

DEM (TRIM), FC, Terrain and Other Inventories

Ecosystem Classification Remote Sensing – Satellite and Airborne and BEC Mapping

• Field Guides • Maps Digital PEM Model PEM Map • Reports Information Systems and • Knowledge • Digital maps Enabling base tools • Attribute Technologies databases Large- • GIS scale BEC • Databases maps • Knowledge management

 . The predictive ecosystem mapping (PEM) procedure.

102 was regarded as a reasonable goal. Recent Based on the satisfactory results obtain- accuracy assessments of  projects ed from our pilot EcoGen project on the around the province range from 65–85%; north coast, we received additional funds therefore, the EcoGen results represent an to complete EcoGen mapping for the acceptable and more cost-effective (a few entire North Coast  (1.95 million ha), cents per hectare vs. a few dollars per and incorporate further reﬁnements to the hectare) alternative to  mapping. knowledge tables and  features. This Most importantly, EcoGen allows us to  mapping project is now completed get maximum use out of existing invento- (Jones 2003). Further reﬁnements to the ries before we decide on where additional biogeoclimatic mapping for the north coast funds should be directed for more detailed (e.g., better linking of the mapping to the ground-based ecosystem inventories.  elevational base) are also complete.

EcoGen Process EcoPrep EcoNGen EcoMap • Prepare GIS • Knowledge • Produce layers engine maps and • Knowledge • Processes databases base knowledge development base

EcoPrep involves: Input coverages

1. Large-scale BEC BEC subzone 2. Selecting primary polygons variant

(e.g., forest cover) Elevation class 3. Creating secondary polygons using slope and Slope/aspect aspect classes class

4. Creating additional GIS Forest cover layers with information type to assess site series in Terrain secondary polygons 5. Creating knowledge base

Overlay

 . The EcoGen predictive ecosystem mapping approach. GIS inventory layers are prepared and overlaid; then the attributes of the resultant polygons are run through a “knowledge table” that is developed for each biogeoclimatic unit. Site series predictions are based on known or expected relationships between polygon attributes and ecosystem characteristics.

103 An independent accuracy assessment plete discussion of site productivity issues) has now been completed for the North to assign site index values to ecosystem Coast  mapping (Yole and Cushon polygons. This ecologically based analysis 2003) and the results indicate that the was compared with the traditional timber CWHvh2 is 75% accurate. As the assess- supply analysis, which uses site productiv- ment did not follow the current provincial ity estimates derived from the (largely old- accuracy protocol (Meidinger 2003), the growth) forest cover inventory. Applying result is not directly comparable to other the EcoGen model and second-growth site map assessments. The result does appear index data to the yield analysis resulted in to indicate, however, that the mapping significant increases to the mid- to long- can be used to predict site series composi- term harvest flow in the pilot area. The tion of forest cover polygons and will thus Land and Resource Management Plan be a useful tool for determining the () Table for the north coast consid- location of potentially operable poor- and ered the implications of using these recent low-site cedar–hemlock forest types. The ecologically based, second-growth site  maps will also be of use for other productivity data for yield analysis. On strategic planning processes including the reviewing the “base case” North Coast implementation of ecosystem-based man- Timber Supply Analysis,  table agement on the coast. members decided to use the traditional A yield analysis project using the five forest inventory productivity estimates, initial EcoGen pilot map sheets is also and to incorporate the latest site produc- finished (Olivotto and Meidinger 2001). tivity data in a “sensitivity analysis” This analysis used second-growth site pro- (North Coast Government Technical ductivity () data from the HyP3 Team 2002). Project (see section 5.3, for a more com-

104 6 OPERATIONAL RESEARCH TRIALS

6.1 Introduction The HyP3 Project established operational This is a more expansive trial and was research trials at Port Simpson and Oona established in 1998 to test some of the River. The trial near Port Simpson, north management ideas gained from both the of Prince Rupert, was established in 1990 Port Simpson trial and the multitude of to examine second-growth productivity in research studies undertaken on CWHvh2/01 the poor cedar–hemlock forest type. sites around Prince Rupert. These two Initially funded by South Moresby Forest operational trial sites are described in Replacement Account () research Chapter 2 (sections 2.6.3 and 2.6.4). Three funds, this study was subsequently taken HyP3 extension notes also provide infor- over by the HyP3 Project in 1999. The mation on the Port Simpson and Oona Oona River operational trial is located on River trials (Appendix 1; Shaw and Banner Porcher Island, south of Prince Rupert. 2001a and 2001b; LePage et al. 2002).

6.2 Port Simpson The Port Simpson operational trial is con- (CWHvh2/01). The major tree species cerned with improving site productivity before harvesting included western hem- on imperfectly to poorly drained sites. lock, western redcedar, and yellow-cedar, The trial addresses two specific issues: with minor amounts of mountain hem- 1. seedling growth response on artificially lock, Sitka spruce, and shore pine. Mean mounded and unmounded microsites; height and diameter at breast height and () of main canopy trees were 20 m 2. seedling nutrition on five substrate and 65 cm, respectively. Gross volume per types created by mixing and mounding hectare was 500 m3 and net volume per treatments. hectare averaged 280 m3. In this study, we hoped to determine Variability in soil composition and the impact of manipulating soil mineral thickness is common on the outer north and organic content on seedling nutrition coast. In general, the soils of the study and growth. To do this, we compared tree area consist of deep surface organic hori- growth between mounded and unmound- zons (average depth 52 cm). This organic ed sites. Although mounding has been layer is primarily composed of forest used for site preparation in other areas of humus on drier microsites and sphagnum British Columbia (McMinn and Hedin peat on wetter sites. This layer usually 1990), this is the first trial established in overlays a thin mantle of mineral soil wet north coastal forests. Some baseline which is often less than 50 cm deep. The hydrological monitoring was also carried soils are mostly classified as Podzolic and out at the Port Simpson operational trial the horizons are derived from metamor- as described in Beaudry et al. (1994) and phic bedrock (schist and gneiss). Beaudry and Sagar (1995) (see Chapter 3, The study area was skidder-logged sections 3.2.5 and 3.4.2). in the late summer and fall of 1990. Following harvest, the treatment area was 6.2.1 Study area description and research divided into eight plots (i.e., four plots as approach The study area is located 30 km mounding treatments and four left as northwest of Prince Rupert near the vil- controls), with an average plot size of lage of Port Simpson (see Figure 2.9), approximately 0.18 ha. A John Deere 790 within the CWHvh2. The study area is  excavator equipped with a bucket largely dominated by the Western red- and thumb attachment created the cedar – Western hemlock – Salal site series mounds (Figure 6.1a). The objective was

105 a b

 . Port Simpson mounding trials: (a) after completion of mounding in 1990; and (b) 6 years after planting.

to build the mounds by overturning one In the spring of 1991, mounded and scoop of soil and then mixing the mineral unmounded plots were planted with equal horizons with the surface organic hori- proportions of western hemlock, western zons. Mounds averaged 0.5 m in height redcedar, and shore pine. Height and and 1.5 m in diameter. Mound density caliper of planted trees were measured varied from 250 to 670 per hectare. The in 1991, 1992, 1994, and 1996. In 1997, mounding treatment resulted in five whole trees were collected from both the substrate types (Table 6.1). The two mounded and unmounded sites (Figure unmounded substrates are controls repre- 6.1b). At that time, 63 trees were manually senting post-harvest conditions typical of excavated to compare root development poorer forested sites of the north coast. In between the mounded and unmounded the mounded treatments, soil variability plots. In addition, 28 soil samples were resulted in three substrate types differing collected for chemical analysis, and foliar by degree of mixing and mineral and samples of new growth were taken from organic composition. the upper crown of 63 planted trees. Soil and foliar samples were collected from each of the five substrate types.  . Substrate descriptions at Port Simpson mounding trial 6.2.2 Port Simpson results Five years Substrate Composition after planting, shore pine and hemlock showed significant treatment effects a A Undisturbed LFH and LFH with (p < 0.05). Both species exhibited a 30% surface disturbance (unmounded) increase in mean height growth and a B Undisturbed peat and peat with surface 66–68% increase in mean caliper growth disturbance (unmounded) on the mounded sites (Figure 6.2). C Mineral mound with low organic Western redcedar, however, did not incorporation exhibit a significant difference between D Mineral mound with moderate to high treatments (p > 0.05). Preliminary results organic incorporation, usually humus show western redcedar did marginally bet- E Organic mound, dominantly O (peat) ter on mounded sites in average height material growth, but differences in caliper growth were negligible between treated and a LFH = forest floor horizons. untreated areas.

106 Although no difference in root to shoot exhibited significant increases in root and ratios was evident between treatments, the shoot biomass between treatments (Figure mean weight of root and shoot biomass 6.3). Both mean above- and below-ground increased on the mounds for all species. biomass doubled for western hemlock and Western hemlock and shore pine both tripled for shore pine on mounded sites. Western redcedar also showed increases in root and shoot biomass between treat- 200 Mean height ments, but the differences were not signi- Mean caliper ficant (p > 0.05). Rooting depth on mounded sites also 150 showed a significant difference for all species (Figure 6.4). Mean rooting depth

Caliper (mm) was 75–100% greater for all three species 100 — growing on mounded sites compared with unmounded sites (Figure 6.5). The mean length of the longest lateral root was also 50 greater on the mounds, especially for Height (cm) western hemlock (28% increase) and shore pine (37% increase). In many cases, 0 Cw Cw Hw Hw Pl Pl lateral roots extended well beyond the (m) (u) (m) (u) (m) (u) limits of the mounds. Species (treatment) In general, western redcedar performed poorly compared with shore pine and  . Mean height and mean caliper of western western hemlock, and showed no signiﬁ- redcedar (Cw), western hemlock (Hw), and cant difference in height and caliper shore pine (Pl) 5 years after planting on mounded (m) and unmounded (u) plots between treatments (p > 0.05). Overall at the Port Simpson study site. mortality throughout the study area was

3 300 Average weight of root Average length of longest lateral root Average weight of shoot 250 Average root depth

2 200

150

Dry weight (kg) 1 100 Length / depth (cm)

0 0 Cw Cw Hw Hw Pl Pl Cw Cw Hw Hw Pl Pl (m) (u) (m) (u) (m) (u) (m) (u) (m) (u) (m) (u)

Species (treatment) Species (treatment)

 . Root and shoot biomass of western redcedar  . Rooting characteristics of western redcedar (Cw), western hemlock (Hw), and shore pine (Cw), western hemlock (Hw), and shore pine (Pl) 6 years after planting on mounded (m) (Pl) 6 years after planting on mounded (m) and unmounded (u) plots at the Port Simpson and unmounded (u) plots at the Port Simpson study site. study site.

107  . Root development of western redcedar growing on unmounded (left) and mounded (right) plots 6 years after planting at the Port Simpson study site.

also greatest for redcedar (68%) compared on pure organic (especially peat, rather with western hemlock (26%) and shore than forest humus) mounds. pine (14%). The increased mortality and Results of the foliar nutrient analysis poorer growth response was largely support these ﬁndings (Figures 6.6 and attributed to the poor condition of the 6.7). In general, shore pine needles from cedar stock (i.e., low root to shoot ratios) seedlings growing on mineral mounds had and heavy deer browsing after planting the greatest needle mass and content of all (seedlings were not initially protected). macro- and micronutrients. The mineral– Although these factors have complicated forest ﬂoor mix of substrate D yielded a the interpretation of treatment effects on western redcedar, the biomass and root 25 growth data showed some positive trends related to treatment. Initial trends suggest that mounding 20 treatments can have a positive effect on shoot growth, above- and below-ground biomass, and root development for 15 seedlings planted on these imperfectly to poorly drained sites (Figure 6.5). The 10 mounding treatment resulted in soil mixing that revealed some other important 5

trends in seedling growth and nutrition. Nitrogen (mg per 100 needles) The variable thickness of mineral and organic horizons, and the nature of the 0 soils throughout the study area, created ABCDE considerable variation in mound charac- Substrate teristics. We observed trends in seedling response that reﬂected this variation in  . Nitrogen content of pine needles substrate type, with the best growth from trees growing on ﬁve occurring on mixed mineral-organic substrate types (see Table 6.1) at mounds and the poorest growth response the Port Simpson study site.

108 8 A B 7 C D 6 E 5

1 Macronutrients (mg per 100 needles)

0 P K Ca Mg S

 . Macronutrient content of pine needles from trees growing on ﬁve substrate types (see Table 6.1) at the Port Simpson study site.

slightly lower needle mass and content of has been improved by the mounding macro- and micronutrients, followed by treatments. Although this may be partially mounded peat (substrate E). The attributed to improvements to microsite unmounded peat of substrate B yielded drainage, the mixing of mineral and the lowest foliar mass and nutrient con- organic horizons, similar to the natural tent of all substrates tested. turbation resulting from windthrow and Because of the dramatic differences in landslide events, is likely the more critical foliar mass among the various substrate element in improving soil nutrient types, foliar nutrient concentrations regimes (Bormann et al. 1995). (expressed as a percentage of foliar We recognize that the Port Simpson weight) did not reﬂect the differences in trial is only a preliminary investigation. productivity. In situations like this (i.e., Future studies should focus on the differ- where a series of treatments gives rise to ences in tree species response to mixing signiﬁcant differences in biomass produc- and mounding treatments, acceptable tion), expressing the foliar nutrient data levels of site disturbance, impacts on in terms of content (milligrams per 100 paludification (see sections 4.3 and 4.4), needles) instead of concentration avoids and optimal treatment methodologies. the “dilution” complications brought Although not included in this trial, yel- about by the biomass differences (Ballard low-cedar is an important species on these and Carter 1986). Interpretations of foliar sites and should be included in future nutrient data are not straightforward in research. The trends we observed at Port these situations, but it is reasonable to Simpson helped direct the design of the conclude from the Port Simpson trial that Oona River operational trial. initial productivity and nutrient uptake

6.3 Oona River The Oona River trial was established lower-productivity western with the overall objective of examining redcedar–western hemlock stands. the ecological and operational feasibility • Test the efﬁcacy of fertilization and of harvesting and regenerating lower- mechanical site preparation treatments productivity forests. This trial set out to: for promoting the establishment and • Assess the feasibility of harvesting growth of natural and planted conifers.

109 • Compare the factors affecting establish- area consists of two adjacent blocks that ment and growth of western redcedar cover a total of 17.6 ha (10.2 and 7.4 ha, following harvesting. respectively). The trial is also situated • Assess and compare the growth per- within the CWHvh2 subzone, formance of planted and natural west- and includes three site series: Western ern redcedar. redcedar – Western hemlock – Salal • Assess the nutritional status of seedlings (CWHvh2/01) covers approximately 84% established on a variety of microsites of the harvested area; Western redcedar – with and without the application of fer- Yellow-cedar – Goldthread (CWHvh2/11) tilizer. covers 10%; and Western hemlock – Sitka • Document the growth history and pro- spruce – Lanky moss (CWHvh2/04) cov- ductivity in lower-productivity, old- ers 6%. Both blocks occur on gentle slopes growth western redcedar–western (5–25%) with a southerly aspect. Soils are hemlock stands and compare this with imperfectly to poorly drained and consist second-growth productivity on similar primarily of organic , or peat veneers sites. over saprolitic veneers (decomposed • Assess the quality of timber harvested schistose bedrock). Soil depth varies from from these lower-productivity stands. 20 cm to over 100 cm. Stands in the area • Document end-product recovery and are dominated by western redcedar, which utilization rates. accounts for about 50% of the volume, and western hemlock, with lesser amounts 6.3.1 Study area description and research of yellow-cedar, Sitka spruce, and shore approach The Oona River trial is located pine. Based on a pre-harvest timber near the community of Oona River on cruise, gross and merchantable volumes Porcher Island, 40 km south of Prince within the CWHvh2/01 site series were Rupert (see Figure 2.9). The operational 333 m3/ha and 235 m3/ha, respectively. In 1998, timber cruising and ecosystem sampling were carried out within a 50-ha candidate area to identify sites dominated by the CWHvh2/01 site series. Using the L. 6786 ecosystem sampling data, together with 11 ﬁeld notes and air photo interpretation, 01 04 an ecosystem map was produced for the study area. Preliminary block boundaries 12 were laid out to include mainly the CWHvh2/01 site series (Figure 6.8). 11 04 O Additional cruise plots were established o 12 na 04 Riv 01 within both blocks to obtain more er 12 detailed information on species distribu- 01 tion, stand structure, and wood quality. Inoperable Forest 12 Detailed soil depth and ecosystem mapping was also conducted on a 50-m grid Operable Forest L. 2203 within each block. A 1:3000 ecosystem– Research Trial soil depth map was produced for both blocks to reﬁne the original block boundaries, identify wetter leave patches (mostly  . Ecosystem map of Oona River study site showing preliminary site series CWHvh2/13 [Western redcedar block boundaries that primarily encompass the Western – Skunk cabbage] and CWHvh2/11), and redcedar – Western hemlock – Salal (CWHvh2/01) site series. plan harvesting and silvicultural treatments.

110 Block harvesting began in June 2000. in height were also felled; since neither Following a diameter limit approach, species was considered as a crop tree for all western redcedar and yellow-cedar the next rotation, leave-tree speciﬁcations between 17.5 cm and 150 cm  were were not required. Hand-felling was com- felled. Western redcedar and yellow-cedar pleted over several weeks. The main skid less than 17.5 cm  were retained for roads were constructed with an excavator crop trees in the next rotation, and those using non-merchantable wood (rotten greater than 150 cm  were retained as logs, snags, and undersized stems) as cor- seed and wildlife trees. The majority of duroy material. One main skid road was hemlock and shore pine greater than 2 m constructed through the centre of each block, with short spurs constructed to access block extremities (Figure 6.9). Logs were “hoe-chucked” to the main skid roads using a  320L, wide-tracked (32- inch) excavator (Figure 6.10) and moved to the haul road by a low-ground-pressure (< 6 )  tracked skidder equipped with chokers (Figure 6.11). Following harvest, twelve 0.1 ha treatment plots were laid out across the two blocks. Uniformity in slope, soil moisture, and soil depth were major criteria for plot selection. Areas dominated by peaty soils (mainly site series CWHvh2/11) were not included in the plots. The site treatments selected for the operational trial were based on existing knowledge of ecosystem processes and the results of the research  . Block 1 at the Oona River study site showing the main corduroy trial established on similar sites near Port skid trail. Simpson (Shaw and Banner 2001a and 2001b). The Port Simpson trial indicated that planted seedlings generally performed better on mounds which consisted of a mixture of organic and mineral soil horizons. In addition, experience on northern Vancouver Island (Prescott and Weetman 1994) has shown good tree growth response to fertilization with nitrogen (N) and phosphorus (P). We, however, hypothesize that the addition of P alone will enhance N availability by stimulating the nitrogen cycle (Cole and Heil 1981; White and Reddy 2000) (See Chapter 4, section 4.5.3). The lower-productivity sites contain a huge amount of organic material (e.g., dead and down trees, humus layers, moss, and vegetation). Disturbance of the sur-  . Excavator “hoe-chucking” logs to main skid trail at the Oona face organic soil layers and the removal River study site. and/or mixing of excess organic material

111 can warm the soil, increase soil aeration, organic and mineral soil horizons to and subsequently improve nutrient avail- form low mounds (Figure 6.13). ability. Surface scarification could also All mechanical treatments were carried create better seedbeds for natural regener- out using a wide-tracked excavator ation of western redcedar. Based on the equipped with either a five-fingered brush above rationale, the following three site rake or a bucket. Disturbance in the treatments were randomly assigned to the remaining area of the blocks (excluding plots (4 replications of each): treatment plots and trails) resulted only 1. Light surface scarification, and raking from logging activities (felling, forward- and piling of slash (Figure 6.12). ing, and excavator travel). 2. Light scarification and raking (as above) Both blocks were planted with a mix- combined with applications of phos- ture of western redcedar (61%) and phorus fertilizer at the rate of 75 kg/ha. yellow-cedar (39%) in April 2002. To 3. Spot-raking followed by mixing the determine optimal regeneration methods for these lower-productivity sites, we will examine the factors that affect the establishment and growth of both natural and planted western redcedar seedlings. These factors include substrate composition, degree of soil disturbance, proximity to seed trees and stand edges, vegetation competition, and deer browsing. After 5 years, we will also assess the nutritional status of planted and naturally regenerated trees, with and without the application of fertilizer. Within the blocks, we will monitor the natural regeneration of all coniferous species (western redcedar, yellow-cedar, western hemlock, shore pine, Sitka spruce, and amabilis fir), and compare the survival rates and growth patterns of natural western redcedar and  . FMC tracked skidder moving logs to the landing at the Oona yellow-cedar with the planted stock. River study site.

 . Excavator raking and piling slash in block 1  . Mixed mineral and organic mound on a at the Oona River study site. CWHvh2/01 site at the Oona River study site.

112 Heavy browsing of western redcedar for stem analysis (Figure 6.15). The sample seedlings by the large deer population on trees were used to gather growth history Porcher Island continues to impede the and old-growth site productivity informa- successful artificial regeneration on operation to refine existing site index and rota- tional sites; therefore, all seedlings planted tion length estimates for these lower- within the treatment plots were protected productivity sites. We will compare the using 122-cm ® rigid tubes, double- growth history data from the operational anchored with cedar and bamboo stakes. trial with data gathered from the Smith These protectors were also used through- Island and Diana Lake old-growth study out the remaining area within the blocks. sites and with ongoing growth studies in Three other seedling protector designs second-growth stands. (Growcone® tubes, Sinocast® cones, and One of the overall goals of the HyP3 Free-Grow® shelters) were also installed Project was to assess the feasibility of con- on a limited number of seedlings. (Figure ducting commercial forestry operations 6.14). We will monitor these protectors to on these lower-productivity sites. Project assess their susceptibility to wind and researchers, therefore, recognized that, in snow damage, and their effectiveness in addition to ecological concerns, questions promoting seedling survival and growth. would arise about the quality and value of To determine how second-growth site the available timber. Two areas of concern productivity compares with that of the were identified: old-growth forests on these low-produc- 1. the utilization levels (volume and tivity cedar–hemlock sites, we needed grade) expected from the timber found some background information on the on these sites; and growth history of the existing old-growth 2. the achievable levels of end-product forest. Before harvesting, we identified 37 recovery. dominant and co-dominant sample trees

 . Seedling protectors tested at the Oona River study site: Free-Grow® (left), Sinocast® (front right), and Growcone® (back right).

113 trial used a random selection of log grades and included logs from the #2, #3, and #4 sawlog and #5 utility grades. For a complete description of log grades, refer to B.C. Ministry of Forests (1994).

6.3.2 Oona River results Pre-harvest ecosystem mapping proved an effective tool in helping to delineate block boundaries. The irregularly shaped, relatively small blocks that resulted from following the boundaries of the CWHvh2/01 site series will not only help to promote the natural regeneration of western redcedar with seeds coming from adjacent stands, but will also blend well into the blanket bog–upland forest landscape pattern (Figure 6.16). Although the Oona River trial consisted mainly of the CWHvh2/01 site series, soil conditions varied considerably throughout the blocks—a situation that had operational implications. For exam-  . Western redcedar sample tree marked for stem-analysis cutting. ple, soil puddling and surface water ponding occurred in some flat or gently sloping areas, especially where soils were shallow. To address the first point, a detailed Excavator mixing and mounding treat- field assessment of log quality was com- ments in these areas were more likely to pleted. This assessment compared stan- degrade the site and produce negative dard timber cruise grades with grades hydrological impacts than to improve obtained from “call-grading.” Log grades microsites for seedling establishment and from a standard cruise are assigned by a growth. Therefore, in the wettest portions computer program that tallies pathologi- of the block, the passes with the excavator cal indicators and compares them with a were minimized and naturally elevated standard database for timber growing on microsites used for planting seedlings. similar sites. With call-grading, each tree Throughout the bulk of the blocks where in a cruise plot is physically checked for slopes were greater than 15–20%, the mix- visible pathological and quality indicators ing and mounding treatments were more and sounded to determine the presence successful in providing beneficial soil dis- or absence of rot. A log grade is then turbance and improving microsite assigned in the field by the cruiser. drainage. Because very limited harvesting of Lower-productivity coastal forests have CWHvh2/01 sites has taken place, an a high degree of structural diversity with assignment of standard cruise-based log many veteran trees and snags. The felling grades is highly suspect. To address con- of these non-merchantable trees during cerns surrounding end-product recovery, harvesting operations can lead to very the volume of dimensional lumber pro- large accumulations of woody slash on duced at the Group Mills sawmill at Oona sites that already have excessively deep River was compared with the scaled vol- surface organic horizons. To reduce the ume of logs entering the mill. The milling amount of organic material (decaying

114  . Aerial view of block 1 at Oona River showing the irregular ecosystem-based boundaries and the individual and patch leave trees.

 . Average percent survival and height a (cm) of planted wood) added to the forest ﬂoor, these western redcedar seedlings at Oona River trees should be left standing wherever possible (Figure 6.16). Trees left as seed Plot no. Treatment Survival (%) Average height (cm) trees and wildlife trees can contribute to C1 Control 98 51.8 habitat diversity goals. Although the C2 Control 98 53.3 diameter limit approach used in this trial C3 Control 100 46.9 proved effective in meeting objectives for C4 Control 100 49.4 both slash management and seed and Average 99.0 50.4 wildlife trees, a liberal interpretation of 4 Mound 100 64.1 the existing wildlife danger tree assess- 5 Mound 98 55.5 ment guidelines was required. Developing 10 Mound 100 56.7 harvesting guidelines for these lower- 11 Mound 100 59.2 Average 99.5 58.9 productivity sites will pose signiﬁcant challenges as the desire to leave as many 3 Rake and Fertilize 100 53.8 veteran green trees and snags as possible 6 Rake and Fertilize 100 52.7 7 Rake and Fertilize 100 50.6 must be tempered with the need for safe- 13 Rake and Fertilize 100 53.0 ty. Chapter 7 provides more details on Average 100 52.5 harvesting and site treatment options and 1 Rake 96 55.2 guidelines for these sites. 2 Rake 98 51.6 In the fall of 2003, survival and height 8 Rake 100 50.9 growth assessments of the planted western 9 Rake 100 55.7 redcedar seedlings took place in each of Average 98.5 53.4 the treatment plots. Overall survival was a Survival and height growth were measured after two growing excellent and exceeded 96% in all treat- seasons (3-year-old trees) ment plots (Table 6.2). This is especially encouraging because of the typically poor

115 survival rate of unprotected seedlings is indeed poor and that the actual site planted in nearby operational blocks and index averages just 4 m for trees that the associated uncertainties in establishing regenerated within the undisturbed old- a viable second-growth crop. Although it growth forest. Stem analysis also revealed is too soon to examine the results for that, on average, these trees take 50 years significant differences in height growth, to reach breast height under the old- some early trends were observed. The growth canopy (see Table 5.1). Preliminary untreated controls showed the least height data collected from second-growth stands growth and the mounded plots showed on the same site series at other locations the best growth (Table 6.2). Both the suggest, however, that the second-growth raked and the raked and fertilized plots site index for western redcedar is actually had similar growth, but averaged only closer to 18 m and the average time to marginally more than the control plots reach breast height is just 7 years (see (Table 6.2). Table 5.1). Mounding or other site prepa- Stem analysis of naturally established ration treatments may reduce this time western redcedar growing in old-growth even further. Although a site index of 18 forests has shown that initial height m is still relatively low for coastal forests, growth is very slow on these CWHvh2/01 it is significantly higher than indicated by sites (see Table 5.1). Across all treatments, the current forest cover inventory (8–10 the average initial height growth rate of m). This information is encouraging and the planted seedlings in clearcuts is reinforces the belief that some level of approximately seven times that of the nat- disturbance to these sites will provide a ural seedlings in old-growth forests (17.9 beneficial boost to tree growth and forest cm/yr vs. 2.6 cm/yr). productivity. Indeed, some sites currently Current site index estimates in the for- classified as “inoperable” because of poor est cover database are derived primarily growth rates may well prove manageable from measurements of old-growth stands. in the near future. Most of the CWHvh2/01 sites are classified Table 6.3 presents a detailed compari- as “low” and have an assigned site index son of log quality, as determined by cruise of 10 m or less. Detailed stem analysis of and call-grade methods, for the trees har- old-growth western redcedar growing on vested from the Oona River operational CWHvh2/01 sites at Oona River confirms trial blocks. The results indicate that the that conifer growth in the existing forests current cruise compilation programs,

 . Cruised and call-graded merchantable timber volumes (m3/ha), by log grade and species, from the Oona River operational research trial

Western redcedar Yellow-cedar Western hemlock Shore pine Sitka spruce Total Call Call Call Call Call Call Log typea Gradea Cruise grade Cruise grade Cruise grade Cruise grade Cruise grade Cruise grade #2 Lumber F 0.6 0.6 #2 Sawlog H 12.3 16.5 4.9 3.9 17.2 20.4 #3 Sawlog I 2.5 9.5 1.7 2.5 3.7 6.6 13.2 #4 Sawlog J 39.4 40.8 16.1 5.8 22.9 8.5 4.9 1.6 14.5 6.8 97.8 63.5 #2 Shingle L 4.7 4.7 #5 Utility U 53.0 16.3 4.0 13.9 24.7 12.0 0.8 4.4 4.8 86.0 47.8 #6 Utility X 2.5 9.6 1.6 0.5 6.3 22.0 1.8 3.5 10.3 37.3 #7 Chipper Y 13.6 25.3 0.7 2.2 1.7 14.9 0.7 1.1 4.5 17.0 47.5 Total 123.2 123.2 22.4 22.4 57.3 57.3 4.9 4.9 27.3 27.3 235.1 235.1 a For log type and grade definitions, see: http://www.for.gov.bc.ca/tasb/legsregs/forest/faregs/scalreg/sr-1.htm#part 1

116 developed for more productive coastal of log profile presents a significant chal- sites, do not provide an adequate portray- lenge for any lumber processing facility al of the log-quality profile obtained from trying to achieve acceptable utilization harvesting lower-productivity western levels. When sawing these western red- redcedar–hemlock stands on the north cedar logs to produce dimensional coast. For western redcedar, the biggest lumber, the high degree of taper and difference between the cruised and call- numerous large branch knots in the top graded volumes was the significant of the tree, combined with the large butt decrease in #5 utility logs. Forty-nine per- flare, can result in significant waste. Initial cent of this volume was moved into higher- results of the Oona River milling data quality and more valuable logs (L grade or show that of a typical tree producing three better). For western redcedar, the field- 5-m logs, the total accumulated waste based method of call-grading resulted in a averaged 46% (27% from the butt log, 24% increase in the volume of sawlogs. 14% from the top log, and 5% from the For the other harvested species, significant centre log). Although the Group Mills decreases resulted in the volume of saw- facility is a basic operation using a twin- logs and a corresponding increase in the bladed circular saw with a 0.25-inch kerf volume of lower-grade utility and chipper for primary breakdown, this amount of logs, again indicating the inadequacies of waste is still within the normal range for the current log-quality profile for these milling western redcedar. More modern sites (Table 6.3). facilities typically experience total accu- The western redcedar growing on the mulated waste in the 45–55% range, imperfectly drained zonal sites on the depending on the log grade milled (P. outer north coast are typically much Edwards, International Forest Products, shorter and have a larger butt flare than pers. comm., 2004; M. Wilson, Delta those growing on better-drained, more Cedar Products Ltd., pers. comm., 2004). productive sites. In addition, the tree tops An increase in end-product recovery in are often dead (spike-topped). This type our study would have been possible if: • shorter pieces of lumber (< 6 ft.) from the butt log were utilized, • less one-inch material was cut, and • the primary headrig was a more efficient, narrow-kerf bandsaw. If logs were processed in a facility with true taper-sawing capabilities, even more volume recovery would be possible. Despite the problems associated with milling the logs, the quality of the western redcedar dimensional lumber and siding produced from these lower-productivity stands is very high (Figure 6.17).

 . Some redcedar siding and dimensional lumber produced at the Group Mills operation at Oona River. Sawlogs were harvested from the nearby operational trial.

117 7 MANAGEMENT INTERPRETATIONS

7.1 Identification Marginally operable, low-productivity in this study. By combining this informa- of Potentially sites in the CWHvh2 belong primarily to tion with HyP3 Project results from our Operable Sites the Western redcedar – Western hemlock intensive study sites and operational trials, – Salal site series (CWHvh2 /01; Banner et we have defined a set of criteria to identify al. 1993). Although there is a range of pro- those CWHvh2/01 sites with the greatest ductivity and species composition within potential for sustainable forest manage- the site series, the vast majority of these ment (Table 7.1). These criteria include: sites are currently outside the operable depth and nature of mineral and organic land base. At the upper end of the pro- soil horizons, bedrock geology, overstorey ductivity spectrum for this site series, and understorey composition, and stand soil and vegetation conditions become volume. Other information, such as loca- transitional to the Western hemlock – tion and accessibility, should be used in Sitka spruce – Lanky moss site series combination with these site factors to (CWHvh2/04), which is currently includ- determine overall operability. ed in the operable land base. At the Ultimately, these site identification lower extremes of productivity for the criteria, and additional information on CWHvh2/01 site series, conditions are bedrock identification and silvicultural transitional to the Western redcedar – strategies, will be summarized in a supple- Yellow-cedar – Goldthread site series ment to A Field Guide to Site Identification (CWHvh2/11), in which standing wood and Interpretation for the Prince Rupert volumes are well below current and pro- Forest Region (Banner et al. 1993). This jected operability limits (typically less than information will help to assess lower-pro- 150 m3/ha). ductivity cedar-dominated sites under We have summarized data from over consideration for harvesting. These crite- 400 ecological plots collected by the B.C. ria are not absolute, however, and the Ministry of Forests between 1978 and the final decision on operability must weigh early 1990s, as well as additional data col- positive indicators against negative ones. lected by HyP3 researchers between 1998 We will further refine the operability cri- and 2002. These data have been used to teria with monitoring information from develop better descriptions of these hyper- the operational trials as we gain more maritime ecosystems, especially for the experience in these forest types. lower-productivity forest types of interest

7.2 Silvicultural A silvicultural system is a cycle of activi- of these systems is typically the produc- Systems ties by which a forest is harvested, regen- tion of timber. The vast majority of har- erated, and tended over time to meet vesting in British Columbia has used the stand or landscape management objec- clearcut silvicultural system. Since the tives. Traditional silvicultural systems, early 1990s, partial cutting or selection ﬁrst developed in Europe during the systems were used to retain some portion 1800s, generally reﬂect the type of regener- of the original stand structure and to ation method employed and the extent of emulate the size and pattern of natural the original forest canopy structure disturbance regimes. In the interior of the remaining after the initial harvest (e.g., province, many of these “retention sys- shelterwood, seed tree, clearcut, strip tems” met a wide variety of ecological and cut). The primary management concern social goals while still allowing for timber

118  . Site identiﬁcation criteria for determining operability on Western redcedar – Western hemlock – Salal (01) sites in the CWHvh2

Operable sites Inoperable sites

Site series phasesa CWHvh2/01a, (01b), more productive sites may be CWHvh2/01c, (01b), sites often transitional to transitional to CWHvh2/04a or 04b CWHvh2/11 or CWHvh2/13

Indicator plant Western redcedar, yellow-cedar, and western hemlock Western redcedar, yellow-cedar, western hemlock, and speciesa are the dominant tree species; Sitka spruce is uncom- shore pine appear scrubby and are largely limited to the mon and of low vigour. Forests are open with numer- shrub layer (≤ 10 m). Mountain hemlock and shore ous spike-topped western redcedar. pine may be more frequent than on “operable” sites. Understorey dominated by Alaskan blueberry, oval- Presence of species indicating poor nutrient availability leaved blueberry, and red huckleberry, as well as and wetter conditions, including Labrador tea, crowber- abundant amounts of salal and false azalea. Lanky ry, lingonberry, sedges, deer cabbage, sphagnum mosses moss and step moss are the dominant moss species. (especially common red sphagnum, common brown Common green sphagnum and skunk cabbage are sphagnum, and fat sphagnum), common scissor-leaf often present, but not dominant. liverwort, Indian hellebore, and Paciﬁc reedgrass. Absence or scattered presence of Labrador tea, crow- Greater dominance of common green sphagnum, and berry, lingonberry, sedges, deer-cabbage, Indian helle- skunk cabbage. Dominance and high vigour of skunk bore, Paciﬁc reedgrass cabbage indicates CWHvh2/13 (swamp forests); avoid harvesting.

Organic soil depth < 30 cm > 30 cm and composition Forest floor horizons (LFH) dominate. Usually com- Peaty organic (O) horizons dominate. These horizons posed of fine roots, wood, bark, and other plant are largely composed of residues from sedges and residues from communities typically associated with sphagnum mosses or other plants associated with soil “upland” sites. A well-developed H horizon is typical. moisture regimes 6–8, with water tables at or near the Peat materials (e.g., residues from sedges and sphag- surface for a significant period during the growing num mosses or other typically “wetland” species) are season. absent or minimal.

Mineral soil depth > 20 cm < 20 cm

Bedrock type schist granodiorite gneiss quartz diorite diorite diorite gneissic diorite gneissic diorite

Minimum stand ≥ 230 m3/hab ≤ 230 m3/hab volume

Height class ≥ 3 ≤ 3

Other operability Sites include some more productive forest patches No higher-productivity sites (usually site series 04) are considerations (usually site series 04) to increase merchantable vol- present in proximity to site. ume and balance costs. Access cuts through signiﬁcant patches of wet forest Area is accessed by minimal disturbance through wet (site series 11, 12, 13) or non-forested wetland (site forests (site series 11, 12, 13) or non-forested wetlands series 31, 32, 33). Sites dominated by slopes less than (site series 31, 32, 33). Sites dominated by slopes 10%. greater than 10%. a Site series phases and plant common names as per Banner et al. 1993. b Minimum stand volume represents net volume of conifers and is based on a minimum DBH of 17.5 cm. These volumes are based on results from the Oona River and Port Simpson operational trials. Operable volumes will vary depending on site-specific costs.

119 harvest. On the coast of British Columbia, patches within the block will provide however, the species composition, ecolog- structural diversity, wildlife habitat, and a ical characteristics, and size of the timber, good seed source for natural western red- combined with the typically steep terrain, cedar regeneration. To increase the total presented significant challenges for the merchantable volume harvested from any application of partial cutting and reten- one unit, it may be desirable to include tion harvesting techniques. As a result, some patches of more productive forest the use of partial cutting systems has been (site series 04 or 05), typically found on limited primarily to single- or group- steeper slopes adjacent to the CWHvh2/01 selection cuts done by helicopter, sites. Some features that determine oper- although ground-based or cable systems ability, such as soil depth and composi- have been successfully used on the south tion and bedrock type, are not discernible coast in recent years. On the central and from air photos and, therefore, initial north coast, however, modern experience block boundaries will require on-site with partial cutting (as opposed to old modification. To reduce overall site dis- selective or high-grading cuts done during turbance and off-site hydrological the early 1900s) is very limited; harvesting impacts, planned access routes to and on the lower-productivity cedar–hemlock through blocks should avoid areas of wet sites has occurred only recently (e.g., forest (site series CWHvh2/11, /12, and /13) Kumealon Inlet over the past few years). and non-forested wetlands (site series These stands present several new opera- CWHvh2/31, /32, and /33). Although not tional concerns that pose challenges for yet tried on these specific sites, it may be sustainable management. For this reason, possible to construct a temporary access we considered several silvicultural sys- road, or a trail across small areas of wet tems, both traditional and non-tradition- forest or bog, using geotextiles or geosyn- al, during the planning of the Port thetics. These products allow a more even Simpson and Oona River operational tri- distribution of loads, stabilize and rein- als. While the primary silviculture objec- force the soil matrix, and reduce rutting. tive of both trials was to re-establish a Avoiding these areas entirely, however, is productive stand of commercially valuable the preferred option. conifers, another important objective at After establishing block boundaries and the Oona River trial was to retain some of delineating leave patches, plans should be the original stand structure and biological made to promote natural western red- complexity. cedar regeneration. Retention of western redcedar seed trees throughout the block 7.2.1 Block layout Pre-harvest ecosystem is highly recommended. Western redcedar mapping of potential harvest units proved seeds are very light (up to 1.3 million seeds an effective tool for the accurate delin- per kilogram), but do not travel very far eation of block boundaries. Air photo from the parent tree (Burns and Honkala interpretation is a critical first step in 1990). To increase the likelihood of ade- defining the initial ecosystem boundaries quate seed dispersal, we recommend that and significantly reduces layout time in the distance between a block boundary the field. Block boundaries should encom- and an individual seed tree (or group of pass the CWHvh2/01 sites and exclude the retained seed trees) be no more than 100 much wetter and typically inoperable m. Seed trees must withstand long-term CWHvh2/11, /12, and /13 site series. If these exposure to wind, often severe on these site series cover greater than 0.1 ha within sites, and retain some amount of a the block, the areas should be flagged as healthy, live crown. Thus, managers must leave patches and assessed for windthrow consider a trade-off in this situation— potential before final layout. Leave seed trees with large, healthy crowns that

120 will provide regular seed crops are more if any merchantable volume. Larger susceptible to windthrow and damage veteran stems located on the richer sites than those with thinner, less vigorous (e.g., CWHvh2/04, /05) harvested in con- crowns (Stathers et al. 1994). This is of junction with these low-productivity particular concern when an isolated tree is stands can be cut. Although specific selec- left. Small groups of trees provide for bet- tion criteria should be determined on a ter long-term stability and are the pre- block-by-block basis, the upper limit on ferred option. Large veteran trees, even the CWHvh2/01 sites typically averages those with significant amounts of stem 100–150 cm . Depending on future rot, can also play an important role as stand structure goals, merchantable shore seed trees. These “vets” produce fewer and pine can either be removed or retained; less frequent seed crops than younger, however, under the Forest Planning and healthier trees, but are usually more stable Practices Regulation (Section 46 [2]) and likely to remain standing during shore pine is only considered an “accept- severe wind events. The size and location able” crop species, and thus seed tree of retained seed trees will ultimately retention is not recommended. If western depend on the stand structure present. hemlock will be a commercial component of the next crop, all mistletoe-infected 7.2.2 Harvesting To maintain or increase hemlock stems higher than 2 m must be tree productivity on the CWHvh2/01 sites, removed. If the hemlock is not infected canopy openings are needed to increase with mistletoe, its retention can act as a sunlight, soil warming, and nutrient avail- wind buffer for western redcedar seed ability. Therefore, some form of clearcut trees, enhance visual quality, or improve with retention harvesting system (e.g., wildlife habitat values. Hemlock retention modified diameter limit) is required. will also maintain some canopy intercep- To define a workable cutting regime, we tion, and thus reduce the potential for highly recommend obtaining additional water table rise. information on stand structure and com- The wet soil conditions typically found position. We suggest conducting at least on lower-productivity sites, combined two cruise plots per hectare (more if stand with the potentially positive benefits of composition and structure is highly vari- harvest and site preparation disturbances able) to collect additional data on diame- on second-growth tree productivity, pres- ter class distribution. These data will ent some significant operational chal- provide a more complete picture of the lenges. Some level of site disturbance is species and size distribution present, and beneficial; however, to avoid site degrada- allow the setting of suitable diameter lim- tion and off-site (hydrological) impacts, its. Upper and lower diameter limits will operators must recognize site- and weather- depend on size and species distribution specific limitations. The CWHvh2/01 site and total volume on the site. A significant series exhibits variable slope and soil char- proportion of the largest diameter western acteristics and these variations result in redcedar veterans should be retained as conditions that respond quite differently seed trees (see section 7.2.1). In addition, to machine traffic. Flat and gently sloping every effort should be made at the time areas with deeper organic soils, and areas of harvest to retain any advance western with thin organic veneers over bedrock, redcedar regeneration. On these low- have greater potential for soil puddling, productivity sites, retaining veteran trees surface water ponding, and (over the should not lower the total harvest volume long-term) paludification. This is especial- significantly as these stems typically have ly true if operations are not suspended high levels of stem rot and provide little, during very wet periods (> 75 mm

121 precipitation in 12 hours). To ensure these ductivity except, perhaps, through some sites are not degraded, the current opera- marginal improvement of surface soil aer- tional shutdown guidelines may require ation. Excessive machine traffic and site revision. Low-ground-pressure, wide- preparation on these non-mineral phases tracked equipment (e.g., excavators with will likely lead to soil puddling, a decrease 32-inch [82 cm] tracks) will minimize the in the number of plantable spots, and a negative effects of machine traffic on these decline in long-term site productivity. The sites, but still provide desirable levels of best strategy on the lithic and peaty phases surface soil disturbance. This equipment is to use naturally elevated microsites is capable of performing multiple func- when choosing plantable spots (e.g., tions, such as trail construction, log for- beside stumps). These sites will only be warding, slash piling, and site preparation. subjected to the surface disturbance creat- Corduroy roads, built of logging slash and ed by harvesting activities, and these activ- dead and down woody material (non- ities should be curtailed during very wet merchantable), should be used for skid- periods. Raking treatments to reduce the ding. Using less material, secondary trails accumulated organic matter and slash can can also be constructed and then pulled be applied to all phases of the CWHvh2/01 apart by the machine operator as the area site series as well as 04 sites. On sites series is cleared of logs. This method not only CWHvh2/11 (occurring mainly on peaty minimizes the site disturbance associated soils), initial treatment results indicate with skid roads, but also aids in slash that harvesting should be avoided wherev- management. During the harvesting phase er possible (see section 7.2.1). of the HyP3 Project, low-ground-pressure Our operational trials show that machines (< 6 psi) such as the  machine operators must receive a basic tracked skidder, proved ideal for trans- level of training to recognize the soil con- porting logs from the block to the landing ditions appropriate for applying site treat- or main haul road. ments. From an operational perspective (based on feedback from the machine 7.2.3 Site preparation treatments Within operators), harvesting and hoe-chucking the CWHvh2, three phases of 01 site series activities should be combined with the site are recognized: 01a – mineral, 01b – lithic, preparation activities to minimize the and 01c – peaty (Banner et. al. 1993). The number of entries into the block. After mineral phase has proved the most suit- assessing soil conditions by visual indica- able for mounding or mixing treatments tors and by test-probing with the excava- because more opportunities are available tor bucket or rake, operators can apply to mix surface organic layers with subsur- the appropriate raking or mounding treat- face mineral horizons. On these sites, low, ments as they retreat from that area of the broad mounds are preferred over higher block. mounds that result in deep pit–mound topography, a condition which favours the 7.2.4 Planting Although harvesting and establishment of sphagnum mosses and mechanically treating the CWHvh2/01 site paludification (see sections 4.3 and sites should encourage natural regenera- 4.4). The lithic phase consists of forest tion of western redcedar, planting should floor () horizons (sometimes over 40 be carried out within 1 year of completing cm deep) occurring directly over bedrock. the site treatments (i.e., allow mixed and The peaty phase is composed of organic mounded spots to settle over a winter soils (generally deeper than 40 cm) before planting). To achieve the optimum derived from sphagnum moss. On sites of planting density, seedlings should be either phase, mounding of pure organic planted on both the naturally raised material is not expected to improve pro- microsites and the artificially created

122 mounds. Western redcedar is the most and quality are also critically important as ecologically and economically suitable a broken stake will result in the loss of the species for these sites and should make up seedling. A 2.5 × 2.5 × 150 cm knot-free the majority of planted stems. Experience wood stake, preferably western redcedar, with planting yellow-cedar on these sites that is driven into the ground a minimum is limited; however, it is a naturally occur- of 30 cm is recommended. Because high ring species and is considered acceptable winds and snow press often cause the as a minor component of the stand (e.g., most damage to seedling protectors, two up to 20%). Although western hemlock stakes per protector may be required is currently listed as a primary species on (Henigman and Martinz 2001). Some pro- these sites (Banner et al. 1993), planting tector designs require only a single stake, is not recommended for the following but may need some sort of additional pin reasons: to prevent the structure from shifting. • natural regeneration will occur on all Protection of seedlings should be done sites; concurrently with planting. • the cost of planting is not justified as As part of our efforts to protect planted the species is of less economic value western redcedar seedlings from deer than western redcedar; and browsing, we recently initiated a research • hemlock dwarf mistletoe (Arceuthobium trial to determine the effectiveness and tsugense) can be a significant problem practicality of using seedlings derived on these sites, thereby reducing overall from rooted cuttings taken from yield and value. unbrowsed, advance western redcedar Browsing of planted western redcedar regeneration. Research shows that deer by coastal black-tailed deer (Odocoileus browsing is sensitive to the levels of hemionus) is often very heavy on these monoterpenes in the foliage (Vourc’h et sites and seedling protection is therefore al. 2001, 2002). The unbrowsed advance considered mandatory. Although various regeneration may contain higher levels of types of seedling protectors are available, monoterpenes, and cuttings taken from the type selected should be at least 1.2 m this root stock could retain this chemical tall. Manual removal of tree protectors defence. In addition, we are examining significantly increases total establishment numerous nursery fertilizer regimes to costs, particularly on remote, difficult to determine whether these affect a seedling’s access sites. We, therefore, recommend palatability to deer. Some combination of protectors that are designed to photo- higher levels of natural chemical defence degrade in 5–8 years (depending on site and altered foliage palatability may even- location and growth rates). Since photo- tually reduce the need to protect seedlings degradation rates are quite inconsistent, from deer browse. Seedlings for these tri- the costs of follow-up site inspections and als were planted at Oona River in the maintenance must be included. Stake size spring of 2004.

7.3 Future Through the HyP3 Project, we have combination of pure science, involving Research learned a great deal about the ecology, co-operation among specialists from relat- Direction hydrology, silviculture, and management ed fields, and practical operational trials of hypermaritime forests and related non- has resulted in some initial management forested ecosystems. This knowledge has guidelines with a solid ecological founda- supplemented our previous experience tion. Nevertheless, we have just scratched gained from over 25 years of ecological the surface in the study of the long-term research in coastal British Columbia. The development of these cedar–hemlock

123 forests following disturbance. Our stem lower second-growth productivity and analysis work in old-growth forests pro- operational potential (though still higher vided some clues about their development than the old-growth stands indicate). that we have compared with initial growth Future operational trials should include a rates in second-growth stands. We still hydrological component to monitor soil face uncertainties, however, about project- and watershed hydrology 1–2 years before ing these growth rates into the future, and forest harvesting and for at least 2 years these will only be lessened with continu- after harvest. This was the intended ing research. approach at the Smith Island study site, Some of the HyP3 scientists have where extensive hydrology data were col- recently initiated an ecosystem recovery lected; however, logistics, economics, and project on the north coast of British visual constraints prevented harvesting on Columbia that involves detailed ecological this site. While we learned a great deal sampling in older second-growth stands. about the baseline hydrology of hyper- While searching for study stands that had maritime watersheds, which allowed us to originated from forest harvesting over the speculate informatively about the hydro- last century, several locations were discov- logical effects of harvesting, we still lack ered where 150–250-year-old, second- actual before and after scenarios. The growth cedar stands had developed after HyP3 studies now provide a wealth of fire, probably Aboriginal burning. Many baseline knowledge and data on which to of these stands represent second-growth build an effective pre- and post-harvest CWHvh2/01 sites and will provide valu- hydrological monitoring program within able data on forest development following future operational trial areas. disturbance. This information, as well as Many opportunities also exist for co- observations (by the authors) of a few operative research with our counterparts recently regenerated cedar-dominated in southeast Alaska. Some joint field trips stands on slash-burnt cutblocks, suggests have already permitted us to observe and that fire may be a potential management discuss common forest ecology and man- tool on CWHvh2/01 sites and thus needs agement concerns. Four high-priority further research. issues have emerged as having the greatest With the completed HyP3 research as potential for co-operative research efforts a foundation, monitoring of our existing (D. D’Amore and P. Hennon, U.S. De- operational trials must continue and new partment of Agriculture Forest Service, trials established throughout the coast. Juneau, Alaska, pers. comm., November, Similar forest ecosystems to those studied 2004): on the mainland coast occur on Haida 1. Developing a common framework in Gwaii/the Queen Charlotte Islands, and which to apply ecosystem classification thus opportunities exist there for the and mapping in coastal British application of results and the establish- Columbia and southeast Alaska. ment of operational trials. Our opera- 2. Using age structure analysis to better tional trials on the mainland coast are all quantify disturbance histories across located on richer metamorphic bedrock. various hypermaritime stand and site Although monitoring of some previously types; in particular, to better quantify established second-growth stands on the the role that wind has played in stand poorer granodiorites was also part of the (and soil) development. HyP3 studies, additional trials on this 3. Quantifying second-growth productivi- widespread bedrock must be established. ty in wet, lower-productivity forest This is necessary to further test our initial types and better defining limits of oper- conclusions that, compared with the ability along the upland forest–bog for- meta- morphic areas, these sites have est continuum.

124 4. Better defining the problem of yellow- tem function. Future research in the cedar decline (i.e., its extent, causes, hypermaritime upland forest–blanket bog implications, and potential solutions). complex should also include components Further development and refinement that continue to examine the soil and veg- of guidelines for these and other shared etation ecology, nutrient cycling, and forest ecology and management issues hydrology of this fascinating landscape. would be significantly enhanced by cross- The research results and operational border co-operation in pure research and recommendations of the HyP3 Project, operational trials. together with future research and opera- Because operational trials are cost- tional trial initiatives of this and related effective and more likely to provide projects, will hopefully contribute to immediate, practical results, they are effective ecosystem- and science-based becoming the favoured research approach. management in coastal areas of British We should not, however, ignore the need Columbia. for continued baseline research on ecosys-

125 APPENDIX 1 HyP3 Project-related Extension Notes

B.C. Ministry of Forests Research extension notes are available at: www.for.gov.bc.ca/rni/Research/Extension_notes/ Extension_Notes.htm

University of British Columbia Extension Series are available from the authors of this report.

Note # Title B.C. Ministry of Forests Research Extension Notes 38 Pattern, process, and productivity in hypermaritime forests: The HyP3 Project 39 Basin hydrology and canopy interception in hypermaritime forests: Issues and approach 44 Excavator mounding to enhance productivity in hypermaritime forests: Preliminary results 45 Effects of soil mixing on foliar nutrient content of shore pine in hypermaritime forests of northern British Columbia: Preliminary results 48 The Oona River operational research trial 49 Canopy interception in a hypermaritime forest on the north coast of British Columbia 50 Moss growth, production, and paludiﬁcation in the hypermaritime north coast of British Columbia 51 Surface water discharge and groundwater storage patterns in a hypermaritime bog near Prince Rupert, B.C. 52 The blanket bog–upland forest complex of north coastal British Columbia: Succession, disturbance, and implications for management 54 Soil biogeochemical dynamics in hypermaritime ecosystems of north coastal British Columbia

University of British Columbia Extension Series (Scientia Silvica) 42 Regeneration, growth, and productivity of trees within gaps of old-growth forests on the outer coast (CWHvh2) of British Columbia

For additional information on the HyP3 Project, please refer to the Web site at: www.for.gov.bc.ca/rni/Research/HyP3/hyp3-pg1.htm

126 GLOSSARY8

Aerobic – occurring in the presence of Folisol – a soil order containing soils oxygen as applied to chemical and bio- composed of upland organic materials, chemical processes; opposite of anaerobic. generally of forest origin, that are greater than 40 cm thick, or at least 10 cm thick if Anaerobic – occurring in the absence of over bedrock or fragmental materials. oxygen as applied to chemical and bio- chemical processes. Gleysol – a soil order containing soils that are saturated with water and under reduc- Basal area – the cross-sectional area at ing conditions either continuously or for a breast height (1.3 m) of all the stems of significant period of the year. interest in a stand over a unit of land area; expressed as m2/ha. Hardpan – horizons or layers in soils that are strongly compacted, hardened, Baseflow – the contribution that ground- cemented, or very high in clay content. water makes in sustaining water yields in a watercourse during periods of no rainfall Hummock – a small, mounded rise of or snowmelt. organic matter and vegetation on a level surface. Biogeoclimatic Ecosystem Classification () – a hierarchical ecosystem Hydraulic conductivity – a coefficient of classification system applied in British proportionality describing the rate at Columbia that describes variation in which water can move through a perme- climate, vegetation, and site conditions. able medium. Brunisol – a soil order containing soils Hydraulic gradient – the gradient or that have sufficient development to slope of a water table. exclude them from the Regosolic order; Hydrograph separation – a technique has a B horizon showing some soil genesis. that uses the composition of water from Bulk density – the mass of dry soil per different sources and in the receiving area unit volume. Also used in this report as to calculate the proportion of the total moss bulk density: g/cm of linear growth water coming from each contributing per square metre. source. Climax vegetation – stable, self-perpetu- Lag time – has various definitions; used ating vegetation that represents the final here to measure the difference between stage of succession. the start of a rainfall event and a measura- ble response in a stream. Colluvium – unconsolidated material moved by gravity, often occurring at mid- Lawn – a level area in a peatland with an dle or lower slope positions. elevation between that of a hummock and a hollow. First-order stream – an unforked or unbranched stream. Two first-order Macropore – a preferential flow channel streams flow together to form a second- whose effect is most pronounced on order stream, two second-order streams infiltration. combine to make a third-order stream, Minerotrophic – receiving nutrients from etc. groundwater containing dissolved minerals.

8 Based in part on Cauboue et al. 1996

127 Net primary production () – the Quick flows – water that is immediately gross primary production of plants minus released from a watershed (see baseflow). the biomass used in respiration by pri- Redox – sometimes reactants gain and mary producers. lose electrons, as in oxidation–reduction, Orographic precipitation – precipitation or redox, reactions. In an oxidation– that results from the lifting of moist air reduction reaction, one reactant is oxi- over an orographic barrier such as a dized (loses one or more electrons) and mountain range. the other reactant is reduced (gains one or more electrons). Overland flow – water that travels over the ground surface to a point of concen- Regosol – a soil order containing weakly tration where turbulent flow occurs. developed soils in which there is not a rec- ognizable B horizon at least 5 cm thick. Paludification – process of bog expansion caused by a gradual rise in water table, or Retranslocation – the movement of development of a perched water table as nutrients between older and newer foliage peat accumulation impedes drainage. within a plant. Mineral soils are transformed into organic Saprolite – bedrock decomposed in situ. soils as bog vegetation expands. Shelterwood – a silvicultural system that Peak flow – the maximum instantaneous involves the retention of a small number discharge of a stream or river at a given of widely dispersed trees for seed produc- location. It usually occurs at or near the tion in order to regenerate a new age class time of maximum flood. in an exposed microenvironment. Predictive ecosystem mapping () – Site index – a species-specific measure of a method of predicting ecosystem occur- forest productivity expressed in terms of rence on the landscape using available height of trees at a specified age (usually spatial data and knowledge of ecological 50 years at breast height in British and landscape relationships. This infor- Columbia). mation is used to automate the computer generation of ecological map units. Site Index – Biogeoclimatic Ecosystem Classification () – site index meas- Perched groundwater – a water table urements tied to the  system. formed by the perching of water on a relatively impermeable layer at some depth Site series – sites capable of producing the within the soil. The soil within or below same mature or climax plant communities the impermeable layer is not saturated within a biogeoclimatic subzone or variant. with water. Soil pipe – subsurface channels parallel to Piezometer – an instrument for measur- the slope that are sufficient in length to ing the pressure head of liquids. influence the flow processes at the hillslope scale. Podzol – a soil order containing soils in which the dominant accumulation prod- Terrain resource inventory mapping uct in the B horizon is amorphous mater- () – the provincial program to pre- ial composed mainly of Fe, Al, and (or) pare computerized base maps for British organic carbon. Columbia at the 1:20 000, 1:250 000, and 1:2 000 000 scales. Preferential flow – water flow through channels in the soil and not the soil Terrestrial ecosystem mapping () – matrix. the stratification of the landscape into

128 map units according to a combination of elevation at which the pressure in the ecological features, primarily climate, water is zero with respect to atmospheric physiography, surficial material, bedrock pressure. geology, soil, and vegetation. Zonal site – a site that is intermediate in Time Domain Reflectrometry () – a soil moisture and nutrient status within a method of measuring soil water content biogeoclimatic unit. The vegetation on a using electromagnetic pulses. zonal site thus reflects the overriding influence of regional climate. Water table – the upper surface of a sub- terrestrial water saturation zone; the

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