Production and Quality of Sap from the Bigleaf Maple (Acer Macrophyllum Marsh) on Vancouver Island, British Columbia

Production and quality of sap from the bigleaf maple (Acer macrophyllum Marsh) on Vancouver Island, British Columbia

Deirdre Bruce B.Sc. in Forestry, University of British Columbia, 2003

A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in the Department of Geography

¬ Deirdre Bruce, 2008 University of Victoria

Production and quality of sap from the bigleaf maple (Acer macrophyllum Marsh) on Vancouver Island, British Columbia

Deirdre Bruce B.Sc. in Forestry, University of British Columbia, 2003

Supervisory Com m ittee

Dr. Dan Smith, Co-Supervisor (Department of Geography)

Dr. W illiam W agner, Co-Supervisor (Department of Geography)

Dr. Dave Duffus , Supervisory Committee Member (Department of Geography)

Dr. Simon Shamoun, External Examiner (Pacific Forestry Centre)

ii iii

Supervisory Committee

Dr. Dan Smith, Co-Supervisor (Department of Geography)

Dr. W illiam W agner, Co-Supervisor (Department of Geography)

Dr. Dave Duffus , Supervisory Committee Member (Department of Geography)

Dr. Simon Shamoun, External Examiner (Pacific Forestry Centre)

Abstract

Bigleaf maple tapping has become increasingly popular on Vancouver Island and additional information is needed to assist in the sustainable development of this non- timber forest product. This research is an exploratory study that investigates sap flow in the 2006/2007 season on Vancouver Island, British Columbia. Sap flow was highly variable throughout the season. Fluctuations in air temperature, above and below zero, were shown to trigger sap flow. This study characterizes the dissolved solid components of the sap and syrup collected during the 2006/2007 season. The carbohydrate content of the bigleaf maple sap is mainly sucrose with a minor component of fructose and glucose. The concentration of carbohydrates varied throughout the season. The main cations in the bigleaf maple sap and syrup are calcium, potassium and magnesium.

iii iv

Table of Contents

Supervisory Committee ...... ii Abstract...... iii Table of Contents...... iv List of Figures...... vi List of Tables ...... vii Acknowledgments...... viii Dedication...... x Chapter One: Introduction ...... 1 1.1 Introduction...... 1 1.2 Forestry in British Columbia ...... 1 1.3 The Potential of Non-timber Forest Products ...... 4 1.4 British Columbia Forest Policy...... 7 1.5 Objectives of The Study...... 9 1.6 References...... 10 Chapter Two: Research Background ...... 13 2.1 Description of the Bigleaf Maple...... 13 2.2 Geographic Distribution...... 15 2.3 Habitat...... 19 2.4 Bigleaf Maple Regeneration ...... 20 2.5 Ecological Importance of the Bigleaf Maple...... 21 2.6 Cultural Importance of the Bigleaf Maple to Coastal First Nations ...... 24 2.7 Bigleaf Maple Management...... 24 2.71 Bigleaf Maple Control ...... 28 2.8 Timber Uses...... 31 2.9 Non-timber Uses ...... 32 2.10 Maple Physiology ...... 33 2.11 Maple Carbohydrates and Cations...... 34 2.12 References...... 37 Chapter Three: Yield and Characteristics of Bigleaf Maple Sap...... 41 3.1 Introduction to Sap Flow Characteristics...... 41 3.2 Methods...... 43 3.2.1 Study Sites and Plot Selection ...... 44 3.2.2 Sap Flow Measurement...... 47 3.2.3 Climate Data ...... 49 3.2.4 Soil Analysis ...... 49 3.2.5 Data Analysis...... 51 3.3 Results and Discussion ...... 52 3.3.1 Sap Flow and Air Temperature...... 52 3.3.2 Seasonal and Monthly Flows...... 56 3.3.3 Soil Type and Flow...... 60 3.3.4 Diameter at Breast Height (DBH) and Flow...... 63 3.3.5 Edge Versus Non-Edge and Flow...... 65 3.5.6 Sap Flow Model...... 66

iv v 3.4 Limitations ...... 67 3.5 Conclusions...... 68 3.6 References...... 70 Chapter Four: Chemical Analysis of Bigleaf Maple Sap and Syrup ...... 72 4.1 Introduction...... 72 4.2 Methods...... 73 4.3 Results and Discussion ...... 76 4.3.1 Bigleaf Maple Sap Carbohydrates and Cations ...... 76 4.3.2 Bigleaf Maple Syrup Carbohydrates and Cations...... 80 4.4 Limitations ...... 84 4.5 Conclusions...... 84 4.6 References...... 86 Chapter Five: Summary ...... 88 5.1 Summary of Research...... 88 5.2 Social Benefits of Syrup Production...... 89 5.3 Tapping into the Economic Benefits...... 92 5.4 Future Research and Forest Management Recommendations...... 96 5.5 References...... 99 Appendix 1...... 101 Vita...... 102

v vi

List of Figures

Figure 1. Bigleaf maple flowers...... 15 Figure 2. The native range of bigleaf maple trees (modified from Minore & Zasada 1990)...... 17 Figure 3. The natural range of bigleaf maple trees in British Columbia (modified from Krajina et al. 1982)...... 19 Figure 4. Bigleaf maple coppice in a cutblock near Port Alberni, Vancouver Island. 21 Figure 5. Heron nests in the bigleaf maple crowns in Stanley Park, Vancouver...... 22 Figure 6. Mosses, lichen and licorice ferns growing on the bigleaf maple stem...... 23 Figure 7. Bigleaf maple coppice ingress in a cutblock...... 25 Figure 8. Notice of herbicide use, posted in the field near Port Alberni...... 30 Figure 9. Map of bigleaf maple study plots on Vancouver Island (see table 2 for the list of numbered study plots)...... 45 Figure 10. A typical study plot of single stems at Glenora, Cowichan Valley...... 47 Figure 11. A 7/16-inch spile (photo by D. Smith)...... 48 Figure 12. Measuring the particle size of the soil samples...... 50 Figure 13. The influence of air temperature and sap flow in Sproat Lake, Port Alberni, from December 31, 2006-February 27, 2007...... 54 Figure 14. The influence of hourly air temperature and sap flow in Nanaimo, from January 16-January 31, 2007...... 56 Figure 15. The highest producing single stem, Sproat Lake, Port Alberni...... 58 Figure 16. Monthly average and total sap flow in the 2006/2007 tapping season...... 58 Figure 17. January total sap yield (l) versus sand content (%)...... 61 Figure 18. January total sap yield (l) and silt content (%)...... 61 Figure 19. January total sap yield (l) and clay content (%)...... 62 Figure 20. Relationship between total sap flow (l) per plot in January versus dbh (cm)...... 65 Figure 21. The distribution of the model residuals over time...... 67 Figure 22. Mean concentrations (ppm) of potassium, calcium and magnesium ...... 80 Figure 23. Comparison of the mean concentration (ppm) of potassium,...... 83 Figure 24. Lawrence Lampson, at Glenora Farms, conducting an educational...... 91

vi vii

List of Tables

Table 1. The rule of 86 equation...... 36 Table 2. List of study plots to correspond with the plot map in ...... 46 Table 3. Number and location of study plots...... 46 Table 4. Seasonal yields from plots (litres) ...... 57 Table 5. Total flow per plot in January 2007 and the average flow per stem (l)...... 60 Table 6. Total sap yield and the average dbh (cm) for the plots in January and February 2007 (l)...... 64 Table 7. Summary of sap samples collected during the 2006/2007 tapping season... 74 Table 8. Comparison of the total solids content of the bigleaf maple ...... 76 Table 9. Average carbohydrate content of sap samples...... 77 Table 10. Average carbohydrate content of murky sap samples...... 78 Table 11. Range of the carbohydrate content (%) and mineral ...... 79 Table 12. Range of the carbohydrate (%) and mineral concentrations (ppm)...... 82 Table 13. List of interviews conducted during this research project...... 92

vii viii

Acknowledgm ents

To my supervisory committee members, Drs. W illiam W agner, Dan Smith

and Dave Duffus, who encouraged and supported me throughout this process.

Special thanks go to the Canadian Forest Service, and more specifically the Pacific

Forestry Centre, who provided financial support and an office space. To the many

technologists and scientists at the Pacific Forestry Centre for their assistance: Dr. Bill

W ilson, Dr. Doug Maynard, Anne Harris, Dr. Simon Shamoun, Linda Bown, Dr.

Brad Stennes, Dr. Brian Titus and Murielle W arbis. A special thanks to Andrew Dyk

for his mapping and technological assistance.

The Agroforestry Industry Development Initiative, for their financial support.

Chris Law, from Sproat Lake Forestry Services, who supported my ideas from the

beginning and assisted me with a truck, seasonal employment and lots of other

forestry equipment. To Clive Dawson and Dave Dunne, at the Ministry of Forest

Research lab, who were extremely helpful with the sap and syrup chemistry.

To Dr. Tim Perkins, from the Proctor Maple Research Center, who always responded

to my emails with insights and recommendations.

Special acknowledgements go the bigleaf maple sapsuckers that assisted with

this research: Harold and Judy Macy, Gary, Katherine and Teesh Backlund, Lawrence

and Annette Lampson, Louis and Gail Lapis, Jay and Nina Rastogi, Sandra and Lon

Gaspardone, Louie and Gary Swaan, Steve and Laura Titus. A special thanks to

Lawrence Lampson, at Glenora Farms, whose enthusiasm and love of the maple

sugaring, motivated me throughout my field season. Also, to all of the volunteers at

Glenora Farms who contributed to the success of the project by trail building, cutting

viii ix firewood, sap collecting and keeping the fire going in the sugar shack. Your dedication to this activity is much appreciated.

To my amazing friends, I am so grateful for your assistance and support during this project: Crystal Tremblay, Colin Robertson, Jocelyn Mandryk, Leta

Smith-Hodgson, Ian Mackenzie, Melanie Mamoser, Angeline Gough, Lynn Koehler,

Lisa Levesque, and Steve Deluca. A special thanks to Soren Jensen for his assistance and encouragement throughout this process.

To my family who have always encouraged me to think outside the box and to ask questions and to explore the unknown. To my brothers, James and Derek Bruce, who encouraged and supported me during this project. To my partner, Troy Beley, who was a healthy distraction throughout this process.

ix x

Dedication

This thesis is dedicated to the diverse forests on Vancouver Island that have been a

source of peace, beauty and wisdom in my life.

Chapter One: Introduction

1.1 Introduction

This thesis examines bigleaf maple tapping on Vancouver Island during the

2006/2007 winter season. As this non-timber resource activity becomes increasingly

popular in some formerly timber dependent communities on southern Vancouver

Island, so does our need to further understand the characteristics of this resource.

This research project involved local citizens who participated in its design and data

collection. This approach was taken in order to build links between researchers and

rural community members, in order to increase the knowledge base and capacity of

all members involved.

1.2 Forestry in British Colum bia

British Columbia is blessed with an abundance of natural resources. Many

communities were therefore built on the expectation that raw resource extraction such

as timber harvesting would sustain their economies over the long term. Significant

transformations in the coastal forest sector in the last decade have been made in an

effort to change from an industrial to a sustainable forest management paradigm. The

publics‘ attention and dismay toward unsustainable forestry practices has caused a

shift towards the economic, social, ecological and legal components of sustainable

forest management. Natural Resources Canada‘s website (2007) states that

sustainable forest management aims to —meet society‘s increasing demand for forest

products and other benefits, while respecting the values that society confers on its forests and preserving forest health and diversity“. Further, innovative technologies

and approaches are integral to the sustainable development of forests and the

economic stability of forest communities (Natural Resources Canada 2007). In

particular, non-timber forest products are emerging as a resource that can sustain

many components of the forest while providing socio-economic benefits.

Today, British Columbia‘s forest industry faces a number of major challenges:

including high resource and extraction costs; high labour costs; low marketability of

remaining stands; downsizing of the pulp industry, a poorly performing US housing

market and reduced competitiveness on the global market (Kozak 2005). Challenges

also face the forest dependent communities where the industry operates. These

communities suffer from market downturns, resource depletion and conflict among

resource users. Many of the problems faced by timber dependent communities result

from traditional, top-down management structures (Bradshaw 2003) and all of these

factors have contributed to massive unemployment in forest dependent rural

communities (Kozak 2005). These challenges have changed societal values regarding

the forest industry and create further pressure to diversify local rural economies

(McFarlane et al. 2003).

Ecologically based, social forestry sustains a wide range of forest conditions and

social and environmental values important to society (Kimmins 1997). Community-

based forest management (CBFM), which is a type of social forestry, encourages

more sustainable forest management outcomes with the full participation of

communities, and is often seen as a way to empower local timber dependent

communities. It can therefore address the need for economic growth (Pomeroy &

Berkes 1998). As conventional forestry starts to wane in British Columbia, small

tenures, such as community forests and woodlots which are increasing in number, are

increasingly recognized for their community networks and local forest knowledge.

Social forestry advocates community-based approaches predicated on the idea that

understanding and the capacity for change, as well as monitoring and enforcement, do

not only reside within the government or the private sector but also at the local level

(W ismer & Mitchell 2005).

The British Columbia Ministry of Forest and Range (BCMoFR) describes a

community forest as any forestry operation managed by a local government,

community group, or First Nation for the benefit of the community (BCMoFR 2007).

In the late 1990s, in response to increasing demand for small scale local forest

operations, the British Columbia Ministry of Forests promised timber reallocation

measures to promote smaller operations, and thus began the community forest pilot

project. Communities and First Nations responded with 27 proposals (BCMoFR

2007). Current community forest invitations include 49 communities and

approximately 700,000 m¹ of timber per year (BCMoFR 2007), providing

opportunities for communities who seek to diversify their economies and to meet

local resource management objectives (BCMoFR 2007).

Community networks can be helpful in identifying specialty and niche markets that

could diversify rural economies (Ambus et al. 2007a). Kozak (2005) states that our

reliance on raw forest commodity products must be reduced and alternative means of

deriving value from the forest explored. Many diversified forest products and market

opportunities exist for small tenure holders (such as woodlots, community forests,

3 private forest landowners and First Nations), which typically do not have the same

economy of scale as industrial forest tenures (Ambus et al. 2007a). Thus, an

opportunity exists for communities to bridge the gap between socio-economic

development and environment conservation. Small tenure holders in British

Columbia have the potential to become leaders in emerging areas of business such as

value added wood products, non-timber forest products and environmental services

(Ambus et al. 2007a). The following sections describe some of the opportunities and

challenges associated with non-timber forest products.

1.3 The Potential of Non-tim ber Forest Products

Non-timber forest products (NTFPs) include a myriad of resources that have been

extracted around the world for millennia. NTFPs are becoming a global tool for the

establishment of sustainable forest communities (Duchesne & W etzel 2002). Despite

this, North America is behind the curve on managing and developing these resources

when compared to the rest of the world (T. Hobby, pers. comm., March 6, 2008).

Because the harvest of NTFPs are currently unregulated in British Columbia, this

creates a range of issues related to such things as over-harvesting, lack of government

revenue, and the infringement of aboriginal rights and traditions uses (Gagne 2004).

This study was designed to provide further insight into the characteristics of bigleaf

maple tapping on Vancouver Island, in order to assist with the sustainable

development of bigleaf maple syrup as an NTFP with commercial potential.

NTFPs– also known as non-wood forest products, botanical forest products and

special forest products– include all of the botanical resources of the forest, excluding

4 volume timber, as well as activities such as ecotourism and recreation (Neumann &

Hirsh 2000; Jones et al. 2002). Some of the products derived from the forests include

foods, such as berries, maple sap products, and wild mushrooms, florals such as salal

and conifer boughs, medicinal and neutraceutical plants such as Devil‘s club, and

restoration products such as seeds (Duchesne et al. 1999). Used for cultural,

recreational, subsistence and commercial purposes, NTFPs include a range of

opportunities for conservation and community economic development and stability

(Cocksedge 2006).

NTFPs have become increasingly important in resource dependent communities in

response to the need for social and economic diversification (Hardy 2002). NTFPs

may provide economic development in areas where the forest industry is in decline or

the numbers of jobs are reduced by the forest industry due to technological changes

(Clapp 1998). Their informal nature, however, has limited the recognition of their

economic significance and NTFPs are only now being recognized for their ability to

provide socio-economic returns while conserving the structure of the forest. A study

by Duchesne et al. (1999), states that NTFPs in Canada provide a critical socio-

economic role at the regional levels as they can provide seasonal employment and

increase yearly family incomes by $8,000 to $10,000.

In Canada, the NTFP industry is largely unmanaged due to the perception that the

industry is marginal and informal (Duchesne & W etzel 2002). However, NTFP are

becoming widely recognized by the public, government and private sectors in

Canada. In British Columbia, estimates from 1997 state that NTFPs provided $700

million to the provincial revenues and it is likely that this value is steadily increasing

(Hallman et al. 1998). The Montreal Process, which identifies criteria and indicators

for sustainable management of temperate and boreal forests, includes NTFPs as an

important criterion (The Montreal Process 1997). NTFPs contribute valuable income

to individuals in forest dependent communities; however it is unlikely that NTFPs can

replace the traditional economic benefits of the forest industry (Duchesne et al. 1999).

The integration of NTFPs into the mainstream forest economy would involve:

increased market awareness and demand; a change in policy (Section 1.4); compatible

management of timber and non-timber values and a change in public perception (W .

Cocksedge, pers. comm., February 27, 2008).

The concept of value added forest products has become increasingly popular as

researchers, industry and private land owners search for ways to remain competitive

and add value to the forests. Hammond (1991) states that a sustainable forest

industry creates more value added products and, consequently, more jobs can be

generated from the forest resources. However, concerns are emerging with regard to

the expanding use of forest. Further, the paucity of science supporting the sustainable

use of forests for NTFPs, along with a shrinking resource base, are also concerns for

this growing sector. The potential risk of —the tragedy of the commons“, such as the

overexploitation of NTFPs in uncontrolled and unmonitored areas, is a concern for

the long term sustainability of NTFPs (Titus et al. 2004). Monitoring of sustainable

harvest levels for NTFPs is limited, mostly because biological monitoring is

expensive, time consuming and requires specialized skills for data collection (Shanley

et al. 2002). The lack of monitoring is considered the most difficult aspect of NTFP

development and conservation (de Jong & Utama 1998). NTFPs can be harvested

6 successfully in the short term; however, the long term sustainability of NTFPs largely

depends on a thorough understanding of their biology and ecology (Duchesne &

W etzel 2002). Understanding how botanical NTFPs grow is essential to promoting

their conservation through sustainable harvesting techniques. In addition, a greater

understanding of the biology of NTFPs will assist gatherers to optimize their harvests

in both the short and long term (Duchesne et al. 1999). Harvesting of NTFPs falls

into the realm of —adaptive management“, where we learn as we go, remain flexible

and adjust practices when outcomes are undesirable (Turner 2001; Armitage 2005).

1.4 British Colum bia Forest Policy

All tenures in British Columbia, whether large or small, follow the rules established

by the provincial forestry legislative as outlined in the Forest Act (BCMoFR 2004).

In an attempt to enhance public involvement and local forest management, small

tenures such as those associated with W oodlot Licenses and Community Forest

Agreements (CFAs) have increased in number. In 2003, the BCMoFR revealed its

Forest Revitalization Plan and announced that it would reallocate 20% of its long-

term agreements to provide tenure for community forests, First Nations, and

woodlots, and expand the amount of timber sold through competitive auction. The

plan created a renewed interest in community forestry throughout rural British

Columbia (Ambus et al. 2007b). In general, these small tenures are expected to

manage multiple timber and non-timber values, which could help revitalize small

communities that have traditionally been —company towns“. Still, these small tenures

are still bound by the same tenure legislation as the larger Tree Farm Licenses (TFL)

7 and Forest Licenses (FL) which has challenged their economic viability. It is to be

seen whether the tenure legislation will be modified for small tenures.

In January 2004 the Forest and Range and Practices Act (FRPA) came into effect,

replacing the former Forest Practices Code of BC Act. This change had implications

for communities submitting applications to the community forest agreement program,

because all applications submitted after this date had to adhere to the new legislation

rather than the Forest Practices Code. In addition, FRPA increased the reliance on

forest professionals for forest planning and operations. In terms of NTFPs, both the

Code (Appendix 1) and FRPA provided legislation for the management of NTFPs;

however, neither were enabled through regulation. The FRPA does not require tenure

holders to consider NTFPs in their Forest Stewardship Plans (BCMoFR 2004) but

does set objectives for cultural heritage values to be reflected in FSPs, which could

include NTFPs of cultural significance to First Nations.

Under the Forest Act, the legislation governing TFLs makes no provisions for the

harvesting of non-timber forest products within the license area. CFA‘s are the only

tenures that specifically refer to NTFPs, but this is not an exclusive right. CFAs

could provide the —right to harvest, manage and charge fees for botanicals as well as

providing permits to harvest“ (BCMoFR 2004). Thus, CFAs could permit NTFPs as

long as their tenure contract explicitly includes NTFP harvest. These rights are not

exclusive and, at this point, are quite vague and unexplored in the province, as

demonstrated from the vague wording in the Act sections for NTFPs, compared to the

rights provided for timber. Timber provides direct value to CFAs because the rights

to timber are exclusive, and any abuse of these rights is punishable through the

Courts. Although CFAs have the right to harvest botanicals, it is important to

recognize that anyone could harvest NTFPs on crown land, as government has chosen

not to enforce property rights due to the low value and impact of harvesting NTFPs.

Thus, little motivation exists for NTFP harvesters to pay a CFA for a permit when it

is currently free to harvest in crown land areas (S. Tedder, pers. comm., February 26,

2008). If CFA holders choose to include rights to NTFPs, —Schedule C“ of the

license document, must include a list of specific botanical species. Management

options for those specific species should be included in the Forest Stewardship Plan

(FSP).

1.5 Objectives of The Study

This thesis project has the following objectives:

1. to compile a literature review on bigleaf maple biology, ecology, current forest management and non-timber potential.

2. to conduct field research to monitor the sap flow in the 2006/2007 tapping season.

3. to determine the carbohydrates and mineral content of the bigleaf maple sap and syrup.

4. to recommend future research and forest management recommendations.

Chapter 2 provides background information on the bigleaf maple ecology, biology,

management, physiology and other relevant characteristics. Chapter 3 summarizes

the results from the sap flow data and examines the influence of air temperature and

other site characteristics and sap flow. Chapter 4 analyzes the carbohydrate and

9 mineral content of the bigleaf maple sap and syrup. Chapter 5 concludes the thesis

with a summary of results and also explores the socio-economic benefits of this

activity, as well as avenues for future research and forest management.

1.6 References

Ambus, L., D.Davis-Case, D.Mitchell and S. Tyler. 2007a. Strength in diversity: market opportunities and benefits from small forest tenures. BC Journal of Ecosystems and Management. 8 (2): 88-99.

Ambus, L., D. Davis-Case, and S. Tyler. 2007b. Big expectations for small forest tenures in British Columbia. British Columbia Journal of Ecosystems and Management. 8 (2): 47-57.

Armitage, Derek. 2005. Adaptive capacity and community-based natural resource management. Environmental Management. 35 (6): 705-715.

Bradshaw, B. 2003. Questioning the credibility and capacity of community-based resource management. The Canadian Geographer. 47 (2): 137-150.

British Columbia Ministry of Forests and Range (BCMoFR). 2004. Forest Act. Queen‘s Printer. Victoria, BC. Available online at http://www.for.gov.bc.ca/tasb/legsregs/forest/foract/contfa.html: last accessed on December 27, 2007.

British Columbia Ministry of Forests and Range (BCMoFR). 2007. Community Forests. No publication information. Available online at http://www.for.gov.bc.ca/hth/community/: last accessed on January 6, 2008.

British Columbia Ministry of Forests and Range (BCMoFR). 2005. Forest and Range Practices Act. Available online at http://www.for.gov.bc.ca/tasb/legsregs/frpa/frpa/frpatoc.htm: last accessed on February 28, 2008.

Clapp, R.A. 1998. The resource cycle in forestry and fishing. The Canadian Geographer. 42 (1): 129-144.

Cocksedge, W endy. 2006. Incorporating non-timber forest products into sustainable forest management. An overview for forest managers. Available online at http://cntr.royalroads.ca/files- cntr/Incorporating%20NTFPs.pdf: last accessed on February 26, 2008. Royal Roads University. 232 p.

10 de Jong, W . and R.Utama. 1998. Turning ideas into action: planning for nin-timber forest products development and conservation. In: E. W ollenberg & A.Ingles (eds). Incomes From the Forest: Methods for the Development and Conservation of Forest Products for Local Communities. CIFOR, Bogor, 43- 55 p.

Duchesne, L.C. and S. W etzel. 2002. Managing timber and non-timber forest product resources in Canada‘s forests: needs for integration and research. The Forestry Chronicle. 78 (6): 837-842.

Duchesne, L.C., J.C. Zasada and I. Davidson-Hunt. 1999. Ecological and biological considerations for sustainable management of non-timber forest products in Northern forests. NTFP conference proceedings. Kenora, Ontario. 6 p.

Gagne, J. 2004. Integrating non-timber forest products into forest planning and practices in British Columbia-Special Report. Forest Practices Board. Victoria, British Columbia. 28 p.

Hallman, R.D., J.Hatfield, and H.E. Macy. 1998. Forest Farming in British Columbia. North American Conference on Enterprise Development through Agroforestry: Farming the agroforest for specialty products. Minneapolis, United States.

Hammond, H. 1991. Seeing the forest among the trees: the case for holistic forest use. Polestart Press Ltd., Vancouver. 309 p.

Hardy, Y. 2002. The Canadian forest service: New directions for science and technology. The Forestry Chronicle. 78 (1): 57-59.

Jones, E.T., McLain, R.J. and W eigand, J. 2002. Non-Timber Forest Products in the United States. University Press of Kansas, Lawrence, Kansas. 445 p.

Kimmins, J.P. 1997. Forest Ecology: A Foundation for Sustainable Management (2nd Ed.) Prentice Hall Inc., New Jersey. 531 p.

Kozak, R. 2005. Research and resource-dependent communities: a world of possibilities. British Columbia Journal of Ecosystems and Management. 6 (2): 55-62.

McFarlane B. L., J.R. Alavalapati, and D. O. W atson (2003) Public values for sustainable forest management in Alberta. In: Shindler, B.A., T.M. Beckley & M.C. Finley. Two paths toward sustainable forests: public values in Canada and the United States. Oregan State University Press, United States. 368 p. .

Natural Resources Canada W ebsite. 2007. Sustainable forest management. Available online at: http://canadaforests.nrcan.gc.ca/articletopic/top_suj4: last accessed on October 19, 2007.

Neumann, R.P. and E. Hirsh. 2000. Commercialization of Non-Timber Forest Products: Review and Analysis of Research. Centre for International Forestry Research, Bogor, Indonesia. 187 p.

Pomeroy, R.S. and R. Berkes. 1998. Two to tango: the role of government in fisheries co-management. Marine Policy. 21(5): 465-480.

Shanley P., A. Pierce, and S.A. Laird. 2002. Beyond timber. Certification of non- timber forest products. In: People and Plants, Forest Trends. Earthscan Publications, London. 456 p.

Titus, B.D., B.K. Kerns, W . Cocksedge, R. W inder, D. Pilz, G. Kauffman, R. Smith, S. Cameron, J.R. Freed, and H.L. Ballard. 2004. Compatible (or co-) Management of Forests for Timber and Non-timber Values. Conference paper presented at: One forest under two flags. Edmonton, Alberta.

Turner, N.J. 2001. —Doing it right‘: Issues and practices of sustainable harvesting of non-timber forest products relating to First Peoples in British Columbia. British Columbia Journal of Ecosystems and Management. 1 (1): 1-11.

The Montreal Process. 1997. Working Group on Criteria and Indicators for the Conservation and Sustainable Management of Temperate and Boreal Forests. First Approximation Report. The Montreal Process Liason Office, Ottawa. 47 p.

W ismer, S. and B. Mitchell. 2005. Community-based approaches to resource and environmental management. Environments. 33 (1): 1-4.

Chapter Two: Research Background

The bigleaf maple (Acer macrophyllum Pursh.) is an economically and ecologically significant broadleaf tree species resident in coastal British Columbia. The literature review in this chapter includes a general description of the biological and ecological values of the bigleaf maple, and describes current and potential management strategies. The chapter also introduces the value of managing the bigleaf maple stands for their timber and non-timber values. Specifically, literature discussing bigleaf maple tapping as a non-timber resource is described in terms of its social and ecological values in timber-dependent communities. Furthermore, this section provides the background information for the analysis of bigleaf maple‘s sap yield, sap sugar content and sap nutrients.

2.1 Description of the Bigleaf Maple

Bigleaf maple is the largest and fastest growing indigenous species of maple occurring in British Columbia. Bigleaf maple trees are sometimes found in pure stands, but are more typically found scattered or in small clusters among other trees species as a minor component of many low elevation coastal forests. The maple is often a pioneer species that grows in disturbed sites such as landslides and harvested cutblocks.

Bigleaf maple trees are recognized for their bright Autumn colours. Although the total numbers of stems are low compared to coniferous tree species in this setting,

13 bigleaf maple trees have the potential to become one of the most valuable deciduous

tree species on the western coast of Canada, especially in the context of value-added

products (Comeau et al. 1999).

Bigleaf maple trees average from 15 to 25 m in height at maturity, but in productive

areas may reach heights of up to 30 m (Peterson 1999). The trunks of bigleaf maple

grow straight; can achieve a diameter of up to 60 cm, and branch into a broad,

spreading crown. They are often forked as several stems tend to grow from a common

base. The bark on the trunks of young bigleaf maples is green, becoming gray brown

and furrowed with narrow ridges on older trees. The older bark is often covered with

mosses, lichens and ferns (Pojar & MacKinnon 1994), and the root system is shallow

and wide spreading.

Bigleaf maple twigs are stout and hairless with opposite branching. The buds are

greenish to reddish and have 3 to 4 pairs of scales. The terminal bud is large,

between 6 to 9 mm long (Farrar 1995). Bigleaf maple trees produce flowers at

approximately 10 years of age. The flowers are yellowish-green approximately 3 mm

in diameter with scented racemes and develop from the same buds as the leaves

(Figure 1). They appear before or during leaf flush. The fruit consists of a winged

samara with paired, hairy, seeds. The fruit matures in the autumn and is dispersed by

wind in the late fall and early winter (Hosie 1973). Buds usually burst in the spring

and the flowers are pollinated by insects (Fowells 1965). At higher elevations, bud

burst can be delayed until May.

Figure 1. Bigleaf maple flowers

The bigleaf maple is known for its exceptionally large leaves; they have the largest leaf of any Canadian maple and the largest undivided leaf of any Canadian tree species (Hosie 1973). The leaves are 15 to 30 cm across and are palmate with five prominent deep lobes. The leaves are opposite, dark green on top and pale, without hairs, below. The leaf stalk releases a milky coloured sap when broken (Hosie 1973).

2.2 Geographic Distribution

There are 115 species of maple found throughout the northern hemisphere. In

Canada there are ten native species of maple trees and two of these, the bigleaf maple and the vine maple, are found in W estern Canada (Fowells 1965). Although many immediate relatives of A. macrophyllum are found in Europe, the bigleaf maple is the only surviving representative of its phylogenetic series on the North American continent (van Gelderen et al. 1994).

Bigleaf maple tree are found in habitats that range in character from mountain valleys and rocky slopes, to stream banks and bottom lands located on the islands and mainland coasts of southwestern British Columbia, W ashington and Oregon states west of the Cascade mountains, and south of the Coast Ranges of California to San

Diego County (Figure 2). The bigleaf maple is also located on the west slopes of the

Sierra Nevada between 600 to 1500 m and on the south slopes of the San Bernardino

Mountains (Peattie 1953). The maple extends as far north as Sullivan Bay on

Broughton Island near the mouth of Kingcome Inlet.

Figure 2. The native range of bigleaf maple trees (modified from Minore & Zasada 1990).

In British Columbia, the abundance of bigleaf maple trees decreases with increasing elevation, continentality and latitude (Klinka et al. 1989). They are found west of the Coast Mountains along the Fraser River to Hope, northward in low elevation valleys to Seton Portage near Lillooet and Siska in the Fraser Canyon

(Figure 3). On Vancouver Island, bigleaf maple trees are found as far north as Port

Hardy (Minore & Zasada 1990, Comeau et al. 1999). The limiting factor for the southern extension of this species is moisture insufficiency; it is likely that the northern extension is limited by air temperature (Klinka et al. 1989). In British

Columbia, bigleaf maple trees are rarely found at elevations above 300 m, however the tree is located at higher elevations at the southern extent of its range (Fowells

1965).

The Council of Forest Industries estimates that at present there are approximately two million m¹ of bigleaf maple (gross volume less decay, waste and breakage) in

British Columbia (Council of Forest Industries 1996). This value almost certainly underestimates the total volume, as this tree species is typically disregarded in forest inventories and this estimate does not include any trees growing on private lands

(Thomas 1999).

Figure 3. The natural range of bigleaf maple trees in British Columbia (modified from Krajina et al. 1982).

2.3 Habitat

In the northern extent of its range in British Columbia, bigleaf maple trees are most commonly found associated with Douglas-fir (Pseudotsuga menziesii var. menziesii), western redcedar (Thuja plicata), grand fir (Abies grandis), western hemlock (Tsuga heterophylla), black cottonwood (Populus trichocarpa), vine maple (Acer circinatum), and W estern yew (Taxus brevifolia) (Fowells 1965). In the southern extent of its range in British Columbia, bigleaf maple trees are typically found growing in the warmest and mildest coastal zones (Klinka et al. 1989). This habitat

19 preference means that bigleaf maple trees are mainly found growing within the

southern Coastal W estern Hemlock (CW H) and the Coastal Douglas-fir (CDF)

biogeoclimatic zones, with limited occurrence in the subcontinental Interior Douglas-

fir zone. The bigleaf maple is found in greatest frequency in the Coastal Douglas-fir

zone (Krajina et al. 1982).

Bigleaf maple trees are found growing in a variety of different soils, from deep

loams to thin soils on rocky slopes (Comeau et al. 1999). Nonetheless, the bigleaf

maple thrives on gravelly soils on fluvial sites and at the base of colluvial slopes

(Comeau et al. 1999). The bigleaf maple requires a persistent supply of soil moisture

and is somewhat flood tolerant (Krajina et al. 1982). Soils that are high in nutrient

concentration, nitrogen to carbon ratio and cation exchange capacity are preferable

(Comeau et al. 1999). The levels of nitrogen, calcium and potassium in the bark,

foliage and litter are high compared to other tree species (Klinka et al. 1990). The

greater abundance of soil macrofauna that is associated with the broadleaf species

(Kilham 1994) stimulates litter decomposition and suggests an increase in the rate at

which nutrients are released.

2.4 Bigleaf Maple Regeneration

Bigleaf maple trees regenerate mainly from seed, increase in size rapidly during

their first 40 to 60 years of growth, and reach maturity between 150 to 300 years in

age. Bigleaf maple trees also readily re-sprout from cut stumps as a coppice, with up

to 30 to 60 shoots (Comeau et al. 1999). W hen maple trees are cut, new shoots sprout

20 from the cut stumps and roots and this is described as a maple coppice. Coppice

growth is vigorous and can exceed 3 m in height per year.

Figure 4. Bigleaf maple coppice in a cutblock near Port Alberni, Vancouver Island.

2.5 Ecological Im portance of the Bigleaf Maple

The bigleaf maple provides extensive ecological benefits in mixed and pure stands, and has received attention for its contribution in maintaining diverse and resilient ecosystems (Comeau et al. 1999). Bigleaf maple trees provide nurse sites on the bole, provide food, cover and nesting sites for animals, including birds, small mammals, insects, and amphibians (Figure 5). In addition, bald eagles (Haliaeetus

leucocephalus) sometimes perch in the tops of bigleaf maple and black cottonwood

trees along riparian areas during the winter (Stalmaster & Newman 1979).

Figure 5. Heron nests in the bigleaf maple crowns in Stanley Park, Vancouver.

Maintaining a component of bigleaf maple trees in mixed wood plantations contributes to the structural diversity in forested areas (Peterson 1999). Taylor (2006) describes bigleaf maple trees as an arboreal ecosystem due to the diverse populations of mosses, liverworts, lichens, bacteria and insects that reside in this vertical ecosystem. This statement is supported by the recognition that the total weight of epiphytes located on bigleaf maples trees is often equivalent to 4 times the weight of the host tree‘s foliage (Comeau et al. 1999). These colonies are supported by the calcium rich bark of bigleaf maples that readily dissolves in the rain and is available

22 for plant growth. In fact, moss layers can be so thick that it forms a —soil“ where tree

roots can establish and grow. Small insects, mites and worms reside in this soil layer.

Licorice ferns, which have edible rhizomes, are often found in the branches and

trunks of the mature maple stems (Pojar & MacKinnon 1994).

Bigleaf maples lose their leaves in the Autumn, providing a rich nutrient reserve for the forest floor. The recycling of nutrients benefits surrounding trees by

increasing the availability of certain elements to the tree roots. The rotting litter also

forms a mull humus layer that is particularly beneficial to the establishment and

growth of W estern redcedar trees.

Figure 6. Mosses, lichen and licorice ferns growing on the bigleaf maple stem.

2.6 Cultural Im portance of the Bigleaf Maple to Coastal First Nations

The coastal First Nations used the bigleaf maple wood to make dishes, pipes and

hooks for clothing (Parish & Thomson 1994). First Nations have termed the bigleaf

maple as the —paddle tree“, as it was the optimal wood for canoe paddles. The inner

bark was used to make baskets, rope and whisks for whipping the berries of

soopalalie, Shepherdia canadensis (L.) Nuttal. The Saanich tribes used preparations

from the bigleaf maple to make medicine to treat sore throats. In addition, the leaves

were rubbed on a boys face at puberty to stop the growth of whiskers (Parish &

Thomson 1994). First Nations have also utilized the leaves for making temporary

containers. The bigleaf maple sap was known to be utilized to make maple syrup,

however, this was not originally done by First Nations people (Pojar & MacKinnon

1994).

2.7 Bigleaf Maple Managem ent

Until recently, this broadleaf tree was viewed as a weed species that needed to be

controlled. However, renewed interest in the value of the coastal hardwood tree

species, such as alder, birch, cottonwood and maple, suggests a shift in attitude is

underway. The new Coastal Forest Action Plan (BCMoFR 2007a) states that

deciduous harvesting supports a high value-added market and could benefit the

coastal economy. This plan emphasizes strategies for harvesting deciduous species

rather than sustainable management.

Bigleaf maple tends to grow in mixed stands with other conifer species; therefore

an improved understanding of the reproductive method of the maple could assist

managers with a management strategy. The ability of the maple to re-grow after

cutting has ensured its continued presence in coastal forests (Figure 7). Since the

coppices from the maple stumps have a wide spreading crown, conifer seedlings may

not receive enough light to survive and grow. If there is no active management, the

maple coppices can dominate a site within 10 years of harvesting (Peterson 1999).

Figure 7. Bigleaf maple coppice ingress in a cutblock.

As the bigleaf maple is a more prolific seed producer than the Douglas-fir, its natural regeneration has posed a challenge to foresters who are trying to manage

25 forest plots solely for conifer seedlings (Pojar & Mackinnon 1994). However, the

most successful establishment of bigleaf maple seedlings is prior to herb and shrub

establishment; as a result, bigleaf maple seedlings tend to be absent in cutblocks due

to vegetation competition, poor seed dispersal and seed predation (Peterson 1999).

Maple competition is more of a concern from the maple sprouts or coppices that grow

prolifically from the stump after cutting. The initial coppice height growth is greater

than the shade intolerant Douglas-fir, contributing to the maple‘s dominance in these

ecosystems (Fowells 1965). Prompt planting of conifer seedlings after harvesting is

recommended in sites where maple grows (Comeau et al. 1999). A study by del

Moral and Cates (1971) states that the maple leaf litter can smother the seedlings and

inhibit seed germination.

Bigleaf maple distribution tends to be clumped and mixed into stands on

Vancouver Island. Retaining a component of bigleaf maple contributes to structural

and species diversity, as well as the aesthetics of the coastal forest (Comeau et al.

1999). In addition, bigleaf maple is resistant to root rot disease (Phellinus weirii

Murrill) and is commonly found in gaps and therefore could be considered a suitable

species for regenerating infected sites (Peterson 1999). It may be best to manage the

maple seedlings and coppices in small groups in defined areas as this could simplify

future management (Comeau et al. 1999). To date, there are currently no stocking

standards for bigleaf maple and research is required to determine appropriate planting

densities (Peterson 1999), which strongly affect the morphology of the maple. At low

densities, branches develop along the whole stem, while at high density, branches are

suppressed and self pruning is induced (Peterson 1999). Managing the bigleaf maple

26 in a mixed stand may require period treatments of pruning and spacing to ensure the

growth of the maple when intermixed with coniferous species (Comeau et al. 1999).

Comeau et al. (1999) recommends cutting the maple stumps close to the ground as

this can result in less decay in the new sprouts and increases the likelihood of strong

root systems. Managing the number of sprouts can greatly improve the quality of the

surviving stems as well as increasing the amount of light to conifer seedlings. Pre-

commercial thinning, between the ages of 5-15, could promote rapid growth and

improve wood quality to the existing stems (Comeau et al. 1999). Therefore, maple

stems should be managed in reasonably dense stands in order to promote growth of a

single stem with few branches (Comeau et al. 1999).

As mentioned above, there are presently no stocking standards for bigleaf maple

trees in British Columbia. Forest managers are bound by the regeneration standards

outlined in the forest development plan (FDP) and the site plan (SP). The obligations

in the site plan determine the stocking requirements on a harvested site and changes

cannot be made to the stocking unless otherwise outlined in the forest development

plan. The SP must be consistent with the FDP and must conform to all other forestry

standards and regulations (BCMoFR 2007b). If changes need to be made, the FDP

can be amended to reflect the change in stocking standards. This power to amend the

FDP provides companies with an option to formulate new strategies if they are

deemed suitable.

Since the bigleaf maple is mostly viewed as a competitor rather than a crop tree, it

is rarely included in FDP. Consequently, there has been little incentive to integrate

this deciduous tree species into a mixed management strategy. Despite this, forest

27 companies are focusing their efforts on removing this species from cutblocks rather

than exploring alternative management strategies. This is evident in the physical and

chemical treatments used to control bigleaf maple establishment, which will be

described in section 2.71.

2.71 Bigleaf Maple Control

Bigleaf maple coppices have been controlled through both physical and chemical

treatments. Biological controls have also been tested with limited results in the field

to date (Lohbrunner 1996). The physical control methods commonly used to control

bigleaf maple trees include manually brushing or slashing. Re-sprouting tends to

occur within 2 to 3 years, so re-treatment is required (Peterson 1999). In order to

decrease re-sprouting vigor, the number of shoots per coppice should be reduced to

one shoot per 25 cm of stump circumference (Peterson 1999). The height of the

stump as also been shown to influence the number of sprouts on the coppice.

Tappeiner et al. (1996) indicates that sprout clump volume for short stumps was

significantly less than for tall stumps. In addition, the sprout clump volume, area and

number of sprouts was lower for maple stems that were cut 1 and 2 years before

harvest of the associated coniferous stand, than for maple trees cut during harvest.

The sprout number was reduced for bigleaf maple in the understory compared to

those in the open (Tappeiner et al. 1996).

A variety of different herbicides has been used to control the resprouting maple.

Some effective treatments include stump applications of triclopyr ester, 2,4-D or

glyphosate, known commercially as Roundup. Basal bark applications of triclopyr

28 and foliar applications of gylphosate have also been utilized and deemed effective.

Herbicides are often combined with manual treatments such as cutting and slashing,

to increase effectiveness.

In British Columbia, triclopyr is the most common herbicide applications used to control maple stems. Triclopyr herbicides are composed of one or two forms of triclopyr, either the triethylamine salt or the butoxyethyl ester. Triclopyr is sold

under a variety of names such as Garlon 3A, Garlon 4, Pathfinder, Remedy, Turflon,

and Release (Cox 2000). Triclopyr kills broadleaf plants by imitating a plant

hormone that causes the growing tips of the plant to elongate, followed by withering

and then the death of the plant (Cox 2000).

In British Columbia, forestry non-broadcast and broadcast pesticide service license

holders must follow the regulations outlined in the Integrated Pest Management Act

and Regulation (BCMoE 2006). A pesticide user permit is required for pesticide use

for the management of forest pests on private land and on areas less than 20 ha on

crown land. Part of this plan requires a public consultation process where comments

and considerations from the community are integrated (BCMoE 2006). Forest

companies and private landowners that are approved for treatments are required to fill

out a notice of herbicide use form and this form is posted at the treatment area for at

least 14 days after the use (Figure 8). A more detailed Pest Management Plan is

required for pesticide treatments of forest pests on more than 20 ha a year of public

land (BCMoE 2006).

Figure 8. Notice of herbicide use, posted in the field near Port Alberni.

The impacts of using herbicide to control the growth of bigleaf maple trees are mixed. A report by the British Columbia Ministry of Forest and Range states that

Release, a formulation of Triclopyr, has limited toxicity. This report (BCMoFR 2003)

states that most of the risks associated with Triclopyr can be avoided with careful

work habits. However, other studies published in the Journal of Pesticide Reform

(Cox 2000) state that herbicide use can have a variety of negative impacts on the

environment and workers‘ health and safety. For example, Triclopyr is mobile in soil

and could potentially contaminate streams, wells and rivers and the associated

wildlife that resides in these moist areas. Bigleaf maple trees are often found in

30 moist, riparian areas and thus herbicides could easily leach into the surrounding

environment. Overall, the research shows that pesticide treatments are controversial.

W ith a surge towards sustainable forest management, it is less likely that

communities will tolerate treatments that could have hazardous effects to the safety of

workers and the environment. As communities become increasingly aware and

involved in public consultation meetings, alternate approaches may be explored to

control bigleaf maple.

2.8 Tim ber Uses

The bigleaf maple tree is exceptional in that it can be used for a variety of different

timber uses. The bigleaf maple wood is moderately hard, cream coloured, diffuse

porous and unimpregnated by tannins (Hosie 1979). First Nations utilized the wood to

make canoe paddles and the second growth coppices were often used for wagon

building (Peattie 1953). To date, the major use of the bigleaf maple is as firewood.

Some of the main alternative uses of the high quality bigleaf maple lumber include

furniture, flooring, musical instruments, boat building, cabinet work, and interior

finish (Peattie 1953). Other value added uses may include fiber or flakeboard that

could be produced from short rotation maple plantations (Thomas 1999). In

particular, it is esteemed for its curly and bird‘s-eye form that is in demand for guitar

makers and other artisans. In the pioneering days in the North-west, curly maple gun

stocks and knives were considered highly valuable by both the Hudson Bay Company

Men and the First Nations (Peattie 1953). Today craftspeople, both local and distant,

may pay premium prices for the curly or quilted grain patterns in the wood. In fact,

31 the curly wood has become so prized that there has been a recent surge of bigleaf

maple tree poaching in W estern W ashington (CBC Radio 2007). Poachers are

illegally cutting valuable maple stems and selling the wood to guitar makers.

2.9 Non-tim ber Uses

NTFPs are an important forest resource in British Columbia, as the benefits can

offset harvesting pressure by providing new and innovative ways to utilize forest

resources. The bigleaf maple tree provides a variety of non-timber uses as outlined in

the bigleaf maple manager‘s handbook for British Columbia (Comeau et al. 1999).

For example, the non-timber values include specialty products, its role in stand

dynamics, and biodiversity and amenity planting in visually sensitive areas. This

section will focus on the different specialty products from the bigleaf maple.

Floral greens have been an important non-timber resource in the Pacific Northwest

(Howell 1991; Peck 1997). Mosses and other epiphytes found on the bigleaf maple

stem are used for the floral and craft trade (Peck 2006). In addition, bigleaf maple

shoots are also utilized for craft materials (Freed 1997). Bigleaf maple syrup is a

non-timber specialty product that is produced from the bigleaf maple trees and the

central topic for this thesis. Syrup from the western bigleaf maple tree is not

currently produced on a large commercial scale but has been a hobby activity for at

least 40 years on Vancouver Island. In addition to the maple syrup, the raw maple

sap can be substituted for water and utilized as a base for soups, tea and even beer and

wine. Tappeiner and Zasada (1993) recommend an increased understanding of the

biology of these resources in order to ensure the sustainable development of non-

32 timber resources. The following sections will summarize relevant research that

provides a greater understanding of the bigleaf maple sap flow and chemistry.

2.10 Maple Physiology

An understanding of the biology and ecology of NTFPs is crucial for the sustainable development of these resources (Duchesne & W etzel 2002). Since there

is very limited research available on the bigleaf maple sap physiology, research from

the sugar maple is utilized to provide further insight. The following two sections will

provide background information on maple sap flow physiology and sap chemistry,

which will complement the field research in chapter three and four.

Despite hundreds of papers on the sugar maple (Acer saccharum Marsh.) sap

exudation dating back to the 17th century, the mechanism is still not fully understood.

The research does indicate, however, that fluctuation in wood temperature above and

below zero are responsible for the sap flow (Heiligmann et al. 2006).

Changes in air temperature create negative and positive stem pressures that induce

the movement of sap within the maple stem. W hen the air temperature falls below

zero and the branches freeze, negative pressure can develop and maple sap is pulled

up the tree (Tyree 1983). Air temperature rises above zero, lead to positive pressures

and, if the internal pressure of the tree is greater than the atmospheric pressure, sap

will flow out the tap hole. Sap continues to flow from the tree until the atmospheric

pressure is greater than the internal pressure of the tree (Marvin 1958). The positive

pressure found within a maple tree is a result of pressure from warm weather,

33 released gasses, osmotic pressure caused by sugar and other substances present in the

sap, as well as gravity (Tyree 1983).

Maple trees are unique from many other trees in that sap is pulled up the tree during

freezing and pushed out during the thaw. This mechanism is due to the properties of

the sapwood (Marvin 1958). The sapwood for all trees is composed of water conduits

or vessels, and provides a pathway for water movement up the tree during periods of

growth (Marvin 1958). The vessels are surrounded by billions of living and dead

wood cells. In most trees, these wood cells are filled with water; in maple trees,

however, the cells are filled with gas (Tyree 1984). W hen the maple branches freeze,

frost begins to form inside the gas filled cells of the wood fibers. The sap is pulled up

through the areas of the sapwood that are not yet frozen and contributes to ice crystals

growing in the cold areas of the tree (Tyree 1984). If the tree thaws, the accumulated

sap moves down the tree under the influence of gravity. The sap is also pushed down

the tree by the gas bubbles in the fiber cells (Tyree 1984).

2.11 Maple Carbohydrates and Cations

Because of its economic importance in eastern Canada, the composition of sap and

syrup produced from the Eastern sugar maple has been examined extensively

(Heiligmann et al. 2006). However, to date no comparable studies have been

undertaken to determine the chemical composition of the bigleaf maple sap and

syrup. Knowing the sugar type and constituents of the bigleaf maple sap could give

syrup producers a greater understanding of the syrup taste and colour, as well as its

potential as a food product.

Sugar maple sap is composed of a mixture of water, sugar and mineral constituents

(Heiligmann et al. 2006). Sugars are produced through photosynthesis and then utilized as a form of energy for cellular functions. Photosynthesis is a process that captures the light and transforms it into sugars, which are later used for growth during the different life cycles of the tree‘s growing season. Photosynthetic products are also stored in the tree as a form of starch, providing an energy source to maintain life processes during the dormant season when there are no leaves on the tree (Campbell

1993). During the winter months, some of the starch is converted to sugars that are dissolved into the raw sap (Heiligmann et al. 2006).

The three main carbohydrates found in sugar maple are glucose, fructose and sucrose. Pure sugar maple syrup is predominantly sugar, with sucrose being the major type, accounting for 88 to 99% of the dry weight of syrup (Heiligmann et al. 2006).

Glucose and fructose are commonly referred to as invert sugars. Glucose, galactose, and fructose are hexose sugars and contain C6H12O6 in their molecular formula

(Campbell 1993). Glucose, the most common monosaccharide, is an aldose with its first carbon double bonded to oxygen. Fructose is a ketose and its structure differs from glucose, as its second carbon is double bonded to an oxygen molecule

(Campbell 1993). Sucrose, the most common disaccharide, consists of a joined glucose and fructose molecule (Campbell 1993). During the spring, when the air temperature increases, sucrose can be converted to invert sugar thus resulting in darker syrup. Invert sugars are produced from the hydrolysis of sugar, which is mainly due to the action of microorganisms (Heiligmann et al. 2006).

The sugar content of sap is a percentage figure that indicates the amount of sugar present as compared to water and other constituents. The proportions are variable; however, sugar maple sap usually consists of 95 to 99% water and 1 to 5% sugar

(Taylor 1956). The rule of 86 applies to the proportion of sap to finished syrup

(Table 1).

Table 1. The rule of 86 equation.

S=86/X

S=Number of gallons of sap to produce one gallon of syrup X=Brix value of the sap 86=Mathematical constant representing the percentage of solids on a weight-volume basis that is in a gallon of syrup

The mathematical equation is not exact because it was developed when —standard density syrup“ had a density of 65.5 ° Brix. Current standard syrup now has a density of 66 ° Brix (Heiligmann et al. 2006). Eighty-six gallons of maple sap containing 1% sugar are required to make 1 gallon of syrup. Sap with a sugar content of 2% requires half as much, 43 gallons of sap, to make 1 gallon of maple syrup. Each time the sugar content is doubled, the amount of sap needed to produce 1 gallon of syrup is reduced by one-half (Taylor 1956).

In addition to the different structure, each carbohydrate has a unique melting point.

The melting point for glucose is 150 ºC, the melting point for fructose is 103-105 ºC and the melting point for sucrose is 185-186 ºC (Campbell 1993). These different melting points indicate the stability of the carbohydrate at different temperatures. An understanding of the carbohydrate content can assist producers with important information on both taste and the evaporation process. Other chemical components

36 of maple sap and syrup include amino acids, proteins, organic acids, minerals, metals

and vitamins. This thesis assesses the minerals and metals in the bigleaf maple sap

and syrup and compares this to the sugar maple.

2.12 References

British Columbia Ministry of Environment (BCMoE). 2006. Integrated pest management act and regulation. Forest pest management sector review paper. Queen‘s Printer. Victoria, British Columbia. Available online at http://www.qp.gov.bc.ca/statreg/stat/I/03058_01.htm: last accessed on January 7, 2008.

British Columbia Ministry of Forests and Range (BCMoFR)a. 2007. Coastal Forest Action Plan. A vision for a competitive and sustainable coastal forest sector. No publication information. Available on line at http://www.for.gov.bc.ca/mof/CoastalPlan/cap07.pdf: last accessed on January 10, 2008.

British Columbia Ministry of Forests and Range (BCMoFR)b. 2007. Site plans and siviculture. No publication information. Available online at http://www.for.gov.bc.ca/code/training/fpc/siteplanning.html: last accessed on January 6, 2008.

British Columbia Ministry of Forests and Range (BCMoFR). 2003. Toxicology and potential health risk of chemicals that may be encountered by forest vegetation management workers-part four: risk to workers using triclopyr formulations (Release or Garlon). Forest Practices Branch, Victoria, British Columbia.

Campbell, N.A. 1993. Biology 3rd edition. The Benjamin/Cummings Publishing Co. Inc., Redwood City, California. 1190 p.

CBC Radio Interview. June 11, 2007.

Comeau, P.G., K.D., Thomas, E.B. Peterson, and M.N. Peterson. 1999. Bigleaf maple managers‘ handbook for British Columbia. British Columbia Ministry of Forests, Victoria. 105 p.

Council of Forest Industries. 1996. British Columbia forest industry fact book: 1996. The Council, Vancouver, British Columbia.

Cox, Caroline. 2000. Triclopyr-herbicide factsheet. Journal of Pesticide Reform. 20 (4): 1-19.

Duchesne, L.C. and S. W etzel. 2002. Managing timber and non-timber forest product resources in Canada‘s forests: needs for integration and research. The Forestry Chronicle. 78 (6): 837-842.

Del Moral, R. and R.G. Cates. 1971. Allelopathic potential of the dominant vegetation in W estern W ashington. Ecology. 52 (1):1030-1037.

Farrar, J.L. 1995. Trees in Canada. Fitzhendry & W hiteside Limited and Canadian Forest Service. Markham, Ontario. 502 p.

Fowells, H.A. 1965. Silvics of Forest Trees of the United States. United States Department of Agriculture, W ashington D.C. 761 p.

Freed, J. 1997. Non-timber products from Pacific Northwest forests. Forestry Update. 23 (3): 1-3.

Hosie, R.C. 1979. Native Trees in Canada, 8th ed. Fitzhenry and W hiteside Ltd. Don Mills, Ontario. 380 p.

Howell, S. 1991. The brush business. Ruralite. 38 (4): 6-11.

Kilham, K. 1994. Soil Ecology. Cambridge University Press. New York. 242 p.

Klinka, K., V.J. Krajina, A.Ceska. and A.M. Scagel. 1989. Indicator Plants of Coastal British Columbia. University of British Columbia Press, Vancouver, British Columbia. 288 p.

Krajina, V.J., K. Klinka, and J. W orrall. 1982. Distribution and Ecological Characteristics of Trees and Shrubs of British Columbia. University of British Columbia Press, Vancouver, British Columbia. 131 p.

Lohbrunner, G.K. 1996. Biological control of the Acer Macrophyllum: Overview of host biology and the screening of fungal isolates with potential to control host growth. Unpublished MSc. Thesis, Simon Fraser University, British Columbia. 66 p.

Marvin, J.W . 1958. The Physiology of Maple Sap Flow. In: W . K.V. Thimann and M. Zimmermann (eds.). The Physiology of Forest Trees. Ronald Press Company, New York.

Minore, D. and J.C. Zasada. 1990. Acer macrophyllum Pursh: bigleaf maple. In R.M. Burns and B.H. Honkala (eds) Silvics of North America: Volume 2,

Hardwoods. Agriculture Handbook 654. United States. Department of Agriculture, Forest Service, W ashington DC.

Parish, R and S. Thomson. 1994. Tree Book: Learning to Recognize Trees in British Columbia. Canadian Forest Service and British Columbia Ministry of Forest. Victoria, British Columbia.

Peattie, D.C. 1953. A Natural History of Western Trees. The Riverside Press, Cambridge, United States. 225 p.

Peck, J.E. 1997. Commercial most harvest in northwestern Oregon: describing epiphyte communities. Northwest Science. 71 (2): 186-195.

Peck, J.E. 2006. Towards sustainable commercial moss harvest in the Pacific Northwest of North America. Biological Conservation. 128 (3): 289-297.

Peterson, K.D. 1999. The Ecology and Silviculture of Bigleaf Maple. Ministry of Forest Research Program. Extension Note 33. Victoria, British Columbia.

Pojar, J. and A. MacKinnon. (eds.) 1994. Plants of Coastal British Columbia. Lone Pine Publishing, Vancouver, British Columbia. 527 p.

Stalmaster, M.V. and J.R. Newman. 1979. Perch-site preferences of winter bald eagles in Northwest W ashington. Journal of Wildlife Management 43 (1): 221-224.

Tappeiner, J.C. and J.C. Zasada. 1993. Establishment of salmonberry, salal, vine maple and bigleaf maple seedlings in the coastal forests of Oregon. Canadian Journal of Forest Research. 23 (1): 1775-1780.

Tappeiner, J.C., J.C. Zasada, D. Huffman and B.D.Maxwell. 1996. Effects of cutting time, stump height, parent tree characteristics and harvest development of bigleaf maple sprout clumps. Western Journal of Applied Forestry 11 (4):120- 134.

Taylor, F.H. 1956. Variation in sugar content of maple sap. Vermont Agricultural Experiment Station Bulletin 587. Vermont, United States.

Taylor, T. 2006. Bigleaf‘s epiphytic ecosystem. Menziesia-Native Plant Society of British Columbia. 11 (2): 1-8.

Thomas, K. 1999. The Ecology and Silviculture of Bigeaf Maple: Extension Note 33. British Columbia Ministry of Forest Research Program., Victoria, British Columbia.

Tyree, M. T. 1983. Maple sap uptake, exudation, and pressure changes correlated with freezing exotherms and thawing endotherms. Plant Physiology. 73 (2): 277-285.

Tyree, M.T. 1984. Maple sap exudation: how it happens. Maple Syrup Journal. 4 (1): 10-11. van Gelderen, D.M., P.C. de Jong, and H.J. Oterdoom. 1994. Maples of the World. Timber Press, Portland, Oregon. 478 p.

Chapter Three: Yield and Characteristics of Bigleaf Maple Sap

3.1 Introduction to Sap Flow Characteristics

Bigleaf maple sap flow involves a sequence of events and processes that remains

inadequately understood. Despite the emerging interest in bigleaf maple syrup and its

potential as a value added product (Comeau et al. 1999), little scientific research has

been conducted on the characteristics of sap flow. W hat understandings we do have

come from extensive history of scientific field and laboratory research on the eastern

sugar maple (Acer saccharum Marsh). These investigations have increased our

understanding of how sap moves through maple trees in the spring, where it is

recognized that sap flow is highly variable throughout the sap flow season and from

year to year (Marvin et al. 1967).

The present study monitors sap flow from bigleaf maple plots located on

Vancouver Island, British Columbia during the 2006/2007 tapping season. Prior

research on the sap flow characteristics of bigleaf maple trees on Vancouver Island is

limited to those included within a tapping guidebook printed by Gary and Katherine

Backlund (2004), a woodlot owner and bigleaf maple syrup producer. Backlund

(2004) notes the following general characteristics of the bigleaf maple tapping on

Vancouver Island:

ñ Flows are unpredictable compared to the sugar maple and sap flow tends to be triggered by a warm spell after a cold snap.

ñ High variability in sap flow is found between trees, even when the trees are growing side by side.

ñ Sap harvests can reach 200 litres per tree and the best production has been found with the smaller diameter trees as opposed to in the East, where the larger diameter trees produce more sap.

ñ Tapping can begin as early as November on into early March and the best flows tend to occur in December and January.

Other bigleaf maple producers have observed that many of the best sap producers are located along the roadside or on the edge of a field (L. Lampson, pers. comm.,

December 15, 2006). This observation may be similar to the findings of research on

Eastern maple trees where the suggestion is that open grown trees tend have a higher amount of xylem tissue and a corresponding greater sap storage capacity; resulting in

the these trees being better sap producers (Moore et al. 1951). Complimentary

research on Eastern maple trees has also shown that air temperature is the main factor

triggering sap flow (T. Perkins, pers. comm., February 10, 2008) (refer to chapter

2.10). Additionally, research on Eastern sugar maples has revealed that relationships

exist between soil texture, water availability and sap flow. The relevant research

indicates that, depending upon the soil type and soil-water availability, enhanced root

growth can lead to an increase in sap production (Tyree 1983).

This exploratory study was intended to provide further information on bigleaf

maple sap flow characteristics that would be of interest to forest land managers and

community groups interested in pursuing bigleaf maple tapping as a non-timber forest

activity. My goal was to develop insights that could assist in the prediction of good

sap flow years and introduce management and production techniques that would be of

value to this developing cottage industry.

3.2 Methods

My research on bigleaf maple sap production on Vancouver Island was intended to

establish the basic sap flow characteristics and, subsequently, to compare them to

Backlund‘s (2004) findings and the findings of comparable research on the eastern

sugar maple. The research necessitated a —hands-on“ community-based approach that

required cooperation and on-site involvement from different producers. In order to

accomplish the research goals, forested areas on southern Vancouver Island were

surveyed for bigleaf maple abundance and permission to tap was acquired from

landowners.

Bigleaf maple trees were tapped during the winter of 2006/2007. The characteristic

of each tree tapped was recorded (ie. dbh) in order assess the relationship between sap

flow and tree size. Immature stems and mature trees were tapped to assess any

differences in flow between coppice and single stem trees. The first taps occurred on

December 6, 2006, with the tapping season ending on March 8, 2007. Following data

collection, the total sap yields of the individual plots were compiled and compared.

This information was also compared with air temperature data, to assess the

relationship between temperature and sap flow.

At each bigleaf maple plot, the general site characteristics were noted (ie. edge

versus non-edge plot location) and representative soil samples were collected to

assess whether soil type influences sap flow. The soil pH, which expresses the

acidity or concentration of H+ ions in a solution, can influence the ability of the tree to

uptake nutrients (Brady & W eil 2002). The pH was established from a mineral soil

43 sample collected from the upper 10 cm of the soil horizon. The soil pH was also

measured to assess and compare the degree of acidity in different maple stands.

3.2.1 Study Sites and Plot Selection

Nineteen bigleaf maple tree plots on Vancouver Island were monitored for sap

flow. The sites were located in the communities of Duncan, Nanaimo and Port

Alberni on Vancouver Island (Figure 9). Duncan and Nanaimo are 50 km apart and

Port Alberni is located 80 km northwest of Nanaimo. The plots were located mainly

on private forest land owned either by private forest companies or individual

landowners. Permission to tap trees and complete sap flow studies was obtained

from the landowner.

Figure 9. Map of bigleaf maple study plots on Vancouver Island (see table 2 for the list of numbered study plots).

Table 2. List of study plots to correspond with the plot map in Figure 9.

Plot Nam e Map Num ber SproatCopp/SS 1-2 Beaufort 3 Drinkwater 4 Hupa 5 SouthPortCopp/SS 6-7 Errington 8 Jinglepot 9 Spruston 10 Yellowpoint 11 Cow Lake 12 GlenoraArea (5 plots) 13-17 Godfrey 18 CowBay 19

W ithin each stand, individual plots consisting of 5 maple trees were selected for monitoring. Both single stems (SS) and coppices (COPP) were chosen for monitoring in order to assess any differences in sap flow (Table 3).

Table 3. Number and location of study plots.

Duncan Nanaim o Port Alberni Total Plots 8 4 7 # Single Stem Plots 6 4 5 # Coppice Plots 2 2

Healthy trees with good access for sap collection and field measurements were chosen for study. Trees with similar diameter at breast height (dbh) were chosen for each plot. The dbh was measured for each individual stem at 1.3 m and then the dbh

was averaged for the plot. The plots were characterized as edge or non-edge,

depending on the location of the trees. Plots located within a forested area were

categorized as ”non-edge‘ and roadside or open plots were recorded as ”edge‘. A total

of 19 plots were monitored for the study.

Figure 10. A typical study plot of single stems at Glenora, Cowichan Valley.

3.2.2 Sap Flow Measurem ent

One taphole was drilled per single stem (SS), with 5 taps established in each plot

Figure 10). For the coppices (COPP), the 3 largest stems were chosen and 1 taphole

(1.3 cm diameter) was drilled into each stem to a depth of 6 to 8 cm, resulting in a total of 15 spiles in each coppice plot. A plastic 7/16-inch spile was inserted into each taphole (Figure 11). The taphole was drilled at a slight upward angle to ensure

that the sap drained along the spile. The spile was lightly tapped with a hammer to

keep it in place.

Figure 11. A 7/16-inch spile (photo by D. Smith).

Sap was collected in 20 l plastic food grade containers through tubes attached to the spiles. Yields were measured volumetrically at the time of collection. New tapholes were drilled every 4 weeks, or when the sap flow ceased. The new tapholes were drilled approximately 6 to 10 cm to the side of and approximately 10 cm above or below the original taphole, resulting in a spiral pattern around the tree.

Sap yields were monitored for the bigleaf maple plots from early December-2006, and continued until bud burst in approximately mid-March-2007. In some cases, sap flows were only monitored for a portion of the season. In all cases, sap yield was only recorded during the high volume month of January. Sap yield was recorded approximately every 3 days. In some cases, sap yield was measured on a daily basis, providing a more detailed examination of sap flow.

3.2.3 Clim ate Data

Records of hourly average air temperature from climate stations located in

Nanaimo, Port Alberni and Glenora, Duncan were obtained from Environment

Canada (Environment Canada 2007). The climate stations were located

approximately 10 km from plot locations at each of the study areas. Although site

specific climatic conditions were likely to differ from the data conditions recorded at

the climate stations, the general air temperature and pressure trends observed at

Environment Canada‘s stations were assumed to be representative of the trends at the

sites over the duration of the study period. The daily average, daily minimum and

daily maximum air temperatures were extracted from the Environment Canada data

for each day.

3.2.4 Soil Analysis

Soil samples were collected from the base of each individual tree at all plots. The

litter layer was screefed down to the mineral soil and a 10 cm mineral soil sample was

collected. The soil samples from each plot were combined and then air dried, on

brown paper for 7 days. The soil was then analyzed for pH and particle size at the

Pacific Forestry Centre‘s laboratory in Victoria, British Columbia.

To prepare the samples for analysis, the dried soil was sieved and then crushed with

a mortar and pestal, in order to break the coarse aggregate. A sub-sample of ≤ 2 mm

fraction was ground to 100 mesh in the Siebtechnic Mill and saved in a 30 gram (60

ml) snap cap vial.

Soil pH was determined by placing 10 grams of fine textured soil in a 50 ml beaker.

20 ml of 0.01 M CaCl2 was added to the soil and the suspension was stirred 2 to 3

times in 30 minutes. Samples were then left for 1 hour, to allow suspended clay to

settle. The pH of the soil was measured by immersion of a calibrated combination

electrode into the supernatant solution. Duplicates were made and results were

recorded as pH in 0.01 M CaCl2.

Particle size was measured using a bouyoucos hydrometer: 50 grams of fine textured 2 mm air dried soil sample was mixed with 100 ml of Calgon solution and

400 ml of distilled water. The suspension was mixed, then transferred to a

sedimentation cylinder and left to equilibrate at room temperature overnight. The

suspension was mixed again with a plunger and within a minute after stirring, a

hydrometer reading was recorded. This process was repeated for all of the samples,

as well as the controls.

Figure 12. Measuring the particle size of the soil samples.

3.2.5 Data Analysis

The sap flow data was summarized for each plot and graphed to compare the

differences in sap flow at different sites. The hourly temperature data was graphically

represented and compared to the sap flow data in 2 sites, where high resolution data

was available. Seasonal yields were summarized for the plots that were tapped the

entire season. In addition, the total sap flow for all of the plots was summarized for

the month of January. Monthly sap flow abundance was graphed to determine the

highest flow month.

The Statistical Package for Social Science (SPSS) 13.0 was used to examine the

relationships between the sap flow and the independent variables, such as dbh and

soil type (% sand). Scatterplots were used to graphically examine the relationships of

sap flow with dbh and soil type. A Mann-W hitney test was used to test for

differences in sap flow for the edge and non-edge plot locations.

A multivariate regression model was constructed to estimate sap flow from a suite

of independent variables. The number of field plots at each location was too low for

individual regression models, so plot data was aggregated temporally into 4 day

intervals. There were a total of 27 observations representing a total of 108 days. The

dependent variable for the model was the total amount of sap flow (l) observed over

all samples within the 4 day window. Independent variables included: air

temperature, soil type (% sand, silt, clay), soil pH and dbh. Air temperature was

represented in the model by a variable expressing the sum of the differences between

the daily minimum and daily maximum for plots where the minimum was less than 0º

C and the maximum was greater than 0 ºC. W here minimum and maximum air

temperatures did not fluctuate around 0 ºC, the temperature variable was set to 0 ºC.

Finally, to capture the variable number of plots contributing to each 4 day period, a

sampling effort variable was included to count the number of observations for each

time period.

To assess the model, the r2 and the individual model coefficients were examined.

Insignificant variables (W = 0.05) were dropped from the model and the model was re- estimated until only significant variables remained. Due to the nature of the data aggregation procedure, the model residuals were tested for temporal autocorrelation

using the autocorrelation function (Brockwell & Davis 1991). Spatial autocorrelation

could not be taken into account because site specific variables were averaged across

plots when aggregated into four day intervals. Furthermore, due to the temporal

aggregation of observations, non-numeric site specific variables, such as edge versus

non-edge plot location and soil texture description, could not be included in the

model.

3.3 Results and Discussion

3.3.1 Sap Flow and Air Tem perature

In Eastern Canada, the relationship between air temperature and fluctuations in

wood temperature are considered the dominant factor contributing to sap flow (Tyree

1983). Spikes in sap flow can occur follow one or more cycles of the air temperature

dropping below 0 ºC and then rising to above 0 ºC the following day. Tyree (1984)

states that sap uptake occurs when the wood temperature decreases however there

52 was much more rapid sap uptake correlated with the onset of freezing exotherm.

High resolution sap flow data was utilized in 2 study sites to describe the effect of air temperature on the bigleaf maple sap flow.

Figure 13 shows the correlation of sap flow and hourly air temperature, in Port

Alberni, from December 31, 2006 through February 27, 2007. A freeze and then

thaw dynamic evident on January 7-8, 2007 (Figure 13), was followed by a rise in sap

flow. Prior to this, there were several days of below 0 ºC air temperatures and on

January 7, 2007, the temperature remained above 0 ºC (average 4 °C) and there was a

spike in flow. The air temperature of the tree canopy must be below 0 ºC in order to

trigger a flow, as the tree branches need to be frozen (Heiligmann et al. 2006). The

temperature near the ground tends to be a few degrees cooler than in the tree canopy

and if the upper branches are not frozen, the sap flow will not be triggered. If the air

temperature is only slightly above freezing, it may be insufficient to cause the tree

branches to freeze (Heiligmann et al. 2006). This may explain why bigleaf maple

producers have not experienced sap flow even though there were freezing conditions

on the ground. Also, after an extended period of low temperatures, it may take

several days of above zero air temperatures for the wood around the tap hole to thaw

and the sap to flow (Heiligmann et al. 2006).

Figure 13. The influence of air temperature and sap flow in Sproat Lake, Port Alberni, from December 31, 2006-February 27, 2007.

From January 10-20, 2007, there was very little sap flow. During this period of time, the average air temperature remained below 0 ºC and the trees likely remained frozen. According to Tyree (1983), the volume of water uptake and the rate of uptake depend on the rate of freezing. For example, a slow freezing rate correlates with a large volume of water uptake while a fast freezing rate correlates with a small volume of water uptake. Thus, a long freeze followed by several days of above and below zero air temperature, could yield excellent flows (Tyree 1983). Although the air temperature may rise above 0 ºC, it is likely that it is not significant enough to trigger flow. It is important to recognize that delayed sap flow often occurs after sub- zero temperatures, as it may take a few days for the wood around the taphole to thaw and the sap to flow (Heiligmann et al. 2006).

On January 22-February 22, 2007, sap flows were steady and the highest yields for the entire season. This may be due to the long freeze from January 10-20, 2007. A drop in sap flow was found between January 25-28, 2007, while temperatures were above 0 ºC; however, flows began to increase when the air temperature rose above and then fell below 0 ºC daily. On February 13-23, 2007, flows level off likely due to the persistence of warm, above zero temperatures for several days. W hen the air temperature remains above freezing, the sap run may last half a day or it may last several days, and the flow may be rapid or slow (Heiligmann et al. 2006). If the small branches remain cool but not frozen on the top of the tree, this can renew the pressure in the tree enough to maintain the flow for a few more hours. An increase in flow on February 24-27, 2007, illustrates the dynamic that daily air temperature above and below 0 ºC triggers flow. This fluctuation in wood temperature creates optimal conditions for sap flow in maples as these temperature changes probably create periods of negative and positive stem pressures (Tyree 1983). W hen the stem pressure is greater than the atmospheric pressure, sap will exude from the taphole (see

2.10).

Figure 14. The influence of hourly air temperature and sap flow in Nanaimo, from January 16-January 31, 2007.

Figure 14 shows the daily sap flow and hourly air temperature from January 14-

January 31, 2007, in the Nanaimo area. Although a short time frame, this site shows

similar sap flow trends with respect to air temperature as documented above. There

was a long period of freezing temperatures from January 10-20, 2007, followed by an

increase in air temperature above zero from January 21-25, 2007 and corresponding

sap flow. Flow slowed down a bit on January 26, 2007, after several days of above 0

ºC air temperatures. Sap flow increased on January 27-28, 2007 when the air

temperature fluctuated above and below 0 ºC.

3.3.2 Seasonal and Monthly Flows

Many landowners re-tap their trees every 3-4 weeks, once the sap flow slows down.

It appears that once the tree is re-tapped, a surge in flow may follow from the newly

56 drilled taphole. Volumes of sap flow for plots tapped for the entire season (December

5, 2006-March 8, 2007) are summarized in Table 4. The seasonal plot totals range

from 93.5 l to 839.4 l. The highest yielding plot (839 l) was located in Sproat Lake,

Port Alberni (Figure 15). The average sap flow per tree in this plot was 168 l for the

entire season. The second highest plot was Sproat Copp, which was located in the

same site as Sproat SS with 496 l. The seasonal total for the lowest producing plot

was 93.5 l. A few of the trees in this plot barely exuded any sap throughout the

season.

Table 4. Seasonal yields from plots (litres) (Dec 2006-March 2007).

Plot Nam e Decem ber January February March Seasonal Total Average Tree Total Standard Deviation SproatSS 171.1 332.8 204.0 131.5 839.4 167.9 87.2 SproatCopp 104.7 260.0 116.5 15.5 496.7 99.3 101.2 GflatCopp1-5 90.7 81.0 93.5 18.4 283.1 56.6 35.4 GflatCopp6-10 104.3 92.0 118.5 19.9 334.7 66.9 43.9 GflatMidSS 66.1 241.6 90.3 26.8 424.7 84.9 94.0 UpperGlSS 26.1 45.4 15.9 6.1 93.5 18.7 16.8

From the plots tapped throughout the entire season, sap flow was broken down into

monthly increments (Figure 16). Most of the sap flow occurred in late December,

late January and again in early February. Thus, the majority of the flow occurred

within a 6 week period.

Figure 15. The highest producing single stem, Sproat Lake, Port Alberni.

Monthly Average and Total Sap Flow

350 Total: 1053 L/m onth

300

250 Total: 639 L/m onth )

L ( 200

w o

l Total: 563 L/m onth Total: 218 L/m onth F

p 150 a S 100

0 Decem ber January February M arch Month Note: Error bars indicate one standard deviation

Figure 16. Monthly average and total sap flow in the 2006/2007 tapping season.

In general, the coppice plots produced less sap than the single stems, even on similar sites. Even though the coppices had 3 taps for each tree, the flow was still lower compared to the single stems with 1 tap. For example, in Table 4, Sproat SS produced 839.4 l while Sproat Copp produced 596.7 l. However, 15 taps were drilled for this plot as opposed to 5 for the SS plot. The average tree flow total was 99.3 l for

Sproat Copp; however, when you divide this by the number of taps, its 33 l on average per stem. This is much lower than 167.9 l per stem for the SS. The same result was found with the Gflat Copp1-5, 6-10, compared with the Gflat Mid SS. The

SS plot produced 424 l for the entire season, while the coppice plots produced 283 l and 334 l.

The results indicate that sap yields are highly variable between and within plots as seen in Table 5. Similar variability in sap yield has been documented for the Eastern sugar maple, as each individual tree differs quantitatively in their response to environmental factors such as air temperature (Tyree 1983). Sap yield from the sugar maple can vary between 4 to 8 l of sap per day (Tyree 1983). Table 5 demonstrates that the bigleaf maple plot yields were also variable, with a range of 33.2-332.8 l in the month of January. The reasons for these differences in sap flow are assumed to be both anatomical and physiological and appear to be the result of genetic factors

(Marvin et al. 1967). Interestingly enough, Marvin et al. (1967) states that a tree with high volume yields are nearly always the same individuals. This has been observed by bigleaf maple tappers, whose best producing trees tend to stay the same.

Table 5. Total flow per plot in January 2007 and the average flow per stem (l).

Cowichan Area Total Flow/Plot Average Flow/Stem GflatCopp1-5 81.0 16.2 GFlatCopp6-10 92.0 18.4 GFlatMidSS 241.6 48.3 GFlatMatSS 131.5 26.3 UpperGlenoraSS 45.4 9.1 CowLakeSS 165.0 33.0 CowBaySS 103.5 20.7 GodfreySS 250.5 50.1 Nanaim o Area JinglepotSS 210.0 42.0 SprustonSS 165.5 33.1 YellowpointSS 301.8 60.4 ErringtonSS 141.5 28.3 Port Alberni Area SouthPortSS 84.5 16.9 SouthPortCopp 82.2 16.4 SproatLkSS 332.8 66.6 SproatLkCopp 260.0 52.0 DrinkwaterSS 33.2 6.6 HupaSS 168.8 33.8 BeaufortSS 93.3 18.7

3.3.3 Soil Type and Flow

Eastern research states that sap yield is positively correlated with the available soil

moisture (Heiligmann et al. 2006). The bigleaf maple, with its shallow roots and

tendency to grow in moist areas, has access to extensive amounts of water, especially

during the rainy winter months on Vancouver Island. The results of the soil texture

analysis tests indicate that the soils were reasonable course textured, with the majority

of the soil samples classified as a sandy loam. A loam is generally characterized as a

mixture of sand, silt and clay particles and tends to exhibit the properties of the

mixture in equal proportions (Brady & W eil 2002). Therefore, a sandy loam is a

loam in which sand is dominant and silt and clay are found in lesser proportions.

Although there was no significant relationship between the soil texture and the sap

60 yield in January, as determined from the Pearson‘s correlation (r=0.33) there was

some interesting information when comparing the individual samples. There was a

somewhat positive relationship between % of sand in the soil sample and sap flow

and a negative relationship between % of clay and silt and sap flow (Figures 17-19).

50 ) l (

d l 40 e i Y

y r a 30 u n a J 20

0 0 20 40 60 80 100 Sand Content (%)

Figure 17. January total sap yield (l) versus sand content (%).

50 ) l (

l 40 e i Y

y r a 30 u n a J 20

0 0 10 20 30 40 50 60 Silt Content (%)

Figure 18. January total sap yield (l) and silt content (%).

50 ) l (

d l 40 e i Y

y r a 30 u n a J 20

0 0 5 10 15 20 Clay Content (%)

Figure 19. January total sap yield (l) and clay content (%).

Although, clay tends to hold more water than sand in a loam, the water is held more tenaciously (Brady & W eil 2002). In addition, the more clay that is present in the

soil, the smaller the pore size and then the greater resistance to root penetration

(Brady & W eil 2002). Thus, it is likely that the distribution of roots is limited in a

soil with a higher percentage of clay and therefore the trees ability to hold water is

reduced. Since the available soil moisture can influence the sap yield, it appears that

the sites with the higher percentage of sand may be a better choice in terms of sap

production. The roots can grow more easily and extend further distances in sandier

soils thus accessing more water. Organic matter may also have an influence as it can

hold more water thus increasing the soil water availability due to its influence on soil

62 structure and total pore space (Brady & W eil 2002). However, the organic matter

was not measured in this research.

Soil pH refers to the degree of alkalinity or acidity of the soil that can influence the

availability for root uptake of elements (Brady & W eil 2002). The pH for the

samples ranged between 4.8-6.07, and did not correlate with the volume of sap yield.

The average pH of the 19 samples was 5.34 which indicate that the soils are acidic,

and completely normal for a forested ecosystem (Brady & W eil 2002). The pH can

influence the availability of plant nutrients. For example, there are less available

macronutrients (Ca, Mg, K, P, N and S) in strongly acidic soils. However,

micronutrients, such as Fe, Mn, Zn, Cu and Co are more available in a lower soil pH

(Brady & W eil 2002). Despite this, it is difficult to make any generalization between

the soil nutrient uptake and soil pH. In general, the bigleaf maple has high nutrient

requirements during the growing season and tends to recycle these nutrients back to

the soil through the leaves and, as a result, it tends to grow on high nutrient potential

sites (Comeau et al. 1999).

3.3.4 Diam eter at Breast Height (DBH) and Flow

Average sap flow showed a positive correlation with larger dbh trees. A Pearson‘s

correlation indicates that the sap flow in January significantly correlates with dbh

(r=0.598). A list of the plots and the average dbh is outlined in Table 6. The average

dbh from the top 5 yielding plots ranged from 40-57 cm dbh. There is a somewhat

positive relationship between sap flow and dbh as seen in Figure 20. However, the

mature plot, with the largest average dbh of 92.6 cm, produced very little sap and was

63 removed from the data set. This low flow may be due to a variety of reasons such as

thickness of bark or old age.

Table 6. Total sap yield and the average dbh (cm) for the plots in January and February 2007 (l).

Duncan Area January (L) February (L) Average dbh (cm ) GFlatCopp1-5 81.0 93.5 19.3 GFlatCopp6-10 92.0 118.5 18.7 GFlatMidSS 241.6 90.25 40 GFlatMatSS 131.5 54.75 92.6 Upper GlenoraSS 45.4 15.9 52 CowLakeSS 165.0 40.7 56 CowBaySS 103.5 23.6 Godfrey 250.5 55.9 53 Nanaim o Area Jinglepot 210.0 112 39.8 Spruston 165.5 121.7 30.4 Yellowpoint 301.8 202.55 49.2 Errington 141.5 84.5 33 Port Alberni Area SouthPort-SS 84.5 43.8 30.8 SouthPort-Copp 82.2 56.5 19 SproatLk-SS 332.8 204 57.6 SproatLk-Copp 260.0 116.5 20.8 Drinkwater 33.2 45.5 50.4 Hupa 168.8 98.8 46.4 Beaufort 93.3 80.1 39.7

Overall, the smaller coppice plots produced less sap that the single stems, although

this was not always the case. Research undertaken on sugar maples indicates that

trees with higher sap flow and sugar content tend to be the larger, faster growing trees

(Moore et al. 1951). This relationship is mainly due to the trees sap storage capacity

which is correlated with the abundance of ray tissues per unit of xylem (Morselli et

al. 1978, W allner & Gregory 1980). Although the tree rings were not analyzed, the

positive correlation between sap flow and dbh may be contributed to the ability of

64 larger stems to store more sap in xylem tissue. Thus, healthy, fast growing maple

trees would be a good choice for sap production.

Total Flow in January Versus DBH

350.0

300.0

) 250.0 L (

w 2 o R = 0.1246 l 200.0 F

t o l

P 150.0

l a t o

T 100.0

50.0

0.0 0 10 20 30 40 50 60 70 DBH (cm )

Figure 20. Relationship between total sap flow (l) per plot in January versus dbh (cm).

3.3.5 Edge Versus Non-Edge and Flow

Sap yield was correlated with the plot location (edge vs. non-edge). The results of

the Mann-W hitney test indicates that sap flow is significantly different in edge versus

non-edge plots (p=0.02). A tree that is located on the edge of a road or a field is

exposed to more sunlight and variations in air temperature than a tree found within a

forested stand. Because of the increased exposure to sunlight, open grown trees can

also be faster growing compared to trees located within a forested site. Many eastern

producers report that roadside trees to be above average sap producers because of

65 their larger crowns, root systems, and better light exposure (Heiligmann et al. 2006).

This higher sap production can also be attributed to the faster growth of open grown

trees and the higher amount of xylem tissue, and hence sap storage tissue in the larger

stems (Moore et al. 1951). It was observed that in many cases, bigleaf maple stems

located in open areas were good producing trees (L.Lampson, pers. comm., December

15, 2006). In terms of sap production, bigleaf maple trees located on the edge of a

field or road may be a good option for tapping.

3.5.6 Sap Flow Model

The regression model predicted total sap flow for each 4 day period. The model (r2

= 0.68) explained a large portion of the variation in sap flow. Sixty-eight percent of

the variation in sap flow in every 4 day period can be predicted by the air temperature

variable and the sampling effort. The overall model was significant (F statistic =

25.9, p < 0.00). The most important predictor was sampling effort (Y = 2.91, t = 3.21)

followed by the air temperature variable (Y = 0.31, t = 2.06). A plot of the model

residuals did not reveal any heteroscedascity, and estimating the autocorrelation

function on the model residuals indicated there was no temporal autocorrelation in

residuals (Figure 21).

The final model parameters are presented in equation 1 below:

sapFlow = -24.3 + samplingEffort * 2.91+ temperatureVar * 0.31

The model was unable to draw out site specific influences on sap flow, likely due

to the data aggregation. However, the importance of daily air temperature fluctuations

66 around 0º C is confirmed to be important for predicting sap flow in bigleaf maple

trees as discussed in section 2.10.

Figure 21. The distribution of the model residuals over time.

3.4 Lim itations

The current study represents the first data reported on the sap flow characteristics

of bigleaf maple trees on Vancouver Island. In order to produce more substantive

results, it is necessary to incorporate many years of data. Volume yields have

produced mixed results in eastern Canada, with some years producing strong

correlations and in other years the correlations have been weak (Marvin et al. 1967).

This project simply describes the trend between air temperature and sap flow in one

tapping season.

The research program was unable to account for microsite climatic differences.

Off-site air temperature readings from remote climate stations are expected to be

different than on-site air temperature readings. Unfortunately, the collection of

microclimate data was not within the scope of the project.

Many environmental and abiotic factors can also have an effect on sap flow length

and volume of flow; however, only the site factors, dbh, soils, edge and non-edge,

were used in this study. Unfortunately, not all individual site specific variables, such

as edge and non-edge plot location, could be included in the model of sap flow.

Further, averaging of variable values in the model likely reduced the explanatory

power and contribution. Detailed site specific data collection could facilitate a more

powerful spatial modeling approach to sap flow.

There was a bias towards site and plot selection due to the participatory nature of

this research project. A greater number of plots would reduce this bias; however the

budget and time frame limited the project scope. Plots could be monitored in

different areas in the Pacific Northwest to extend these research findings to other

geographic regions.

3.5 Conclusions

This study documented one bigleaf maple sap flow one season. The bulk of the sap

flow occurred during a 6 week period, starting at the end of December 2006 through

to the beginning of February 2007. The highest flows were found during January

2007. Although the weather conditions are milder on the west coast compared to the

east coast, the above and below zero fluctuations are sufficient to trigger sap flow, as

68 seen with the sugar maple in the east. In addition, the sap flow model suggested that

air temperature changes above and below 0º C, was significant for determining sap

flow in the bigleaf maple. Thus, it is important for producers to continually monitor

the 5 day forecasts to determine when freezing conditions are expected.

Sap flow from the plots varied greatly, with seasonal plot totals ranging from 93.5

to 839.4 l. These findings are similar to those reported for sugar maple, where there

is high variability in sap flow between individual stems and also between different

sections of the same stems (Johnson 1945). Single stems plots had greater flows than

the coppice plots, even in the same site locations. Given that high producers tend to

stay the same year after year (Taylor 1956), landowners should take note of their high

producing trees.

Edge or roadside plots produce more sap than forested plots. This is likely due to

the increased sunlight and attendant growth of the maples found along roads or on the

edge of fields. In addition, the larger dbh plots appeared to produce slightly more sap

than the smaller dbh plots. This may be due to the higher storage capacity of the ray

tissue in the xylem of the larger diameter trees. Soils that consist of a higher % of

sand have a greater flow, but this was not statistically significant. Many other factors

may have an influence on the sap flow, including soil temperature, soil moisture and

temperature throughout the preceding months.

This study provides a start at characterizing bigleaf maple sap yield and provides

some baseline information on the factors that may influence sap flow. This

information is valuable to land managers, community groups and private forest

69 landowners interested in developing a greater understanding of this non-timber

resource.

3.6 References

Backlund, G. and K. Backlund. 2004. Bigleaf Sugaring: Tapping the Western Maple. Backwoods Forest Management, Ladysmith, British Columbia. 98 p.

Brady, N.C and R.R. W eil. 2002. The Nature and Properties of Soils: Thirteenth Edition. Prentice Hall, New Jersey. 960 p.

Brockwell, P.J., and R.A. Davis. 1991. Time Series: Theory and Methods. 2nd Ed. Springer-Verlag. New York. 577 p.

Comeau, P.G., K.D., E.B.,Thomas, and N.M. Peterson. 1999. Bigleaf Maple Managers‘ Handbook for British Columbia. British Columbia Ministry of Forests, Victoria. 105 p.

Environment Canada. 2007. Climate Data Online. Available online at: http://www.climate.weatheroffice.ec.gc.ca/W elcome_e.html; last accessed on November 15, 2007.

Johnson, L.P.V. 1945. Physiological studies on sap flow in the sugar maple, Acer saccharum Marsh. Canadian Journal of Resource Management 23 (1): 192- 197.

Heiligmann, R.B., M.R., Koelling, and T.D. Perkins (eds.). 2006. North American Maple Syrup Producers Manual (2nd ed.). For Sale Publication. The Ohio State University, United States. 329 p.

Marvin, J.W .M., Morselli., and F.M. Laing. 1967. A correlation between sugar concentration and volume yields in sugar maple-an 18-year study. Forest Science. 13 (4): 346-351.

Moore, H.R., W .R. Anderson and R.H. Baker. 1951. Ohio maple syrup-some factors influencing production. Ohio Agricultural Experiment Station Research Bulletin. 718. 53 p.

Morselli, M.F., J.W . Marvin, and F.M. Laing. 1978. Image analyzing computer in plant science: more and larger vascular rays in sugar maples of high sap and sugar yield. Canadian Journal of Botany. 56 (1): 983-986.

Taylor, F.H. 1956. Variation in sugar content of maple sap. Vermont Agricultural Experiment Station Bulletin 587. Vermont, United States.

Tyree, M. T. 1983. Maple sap uptake, exudation, and pressure changes correlated with freezing exotherms and thawing endotherms. Plant Physiology. 73 (2): 277-285.

Tyree, M.T. 1984. Maple sap exudation: how it happens. Maple Syrup Journal. 4(1): 10-11.

W allner, W .E. and R.A. Gregory. 1980. Relationship of sap sugar concentrations in sugar maple to ray tissue and parenchyma flecks caused by Phytobia setosa. Canadian Journal of Forest Resources. 10 (3): 312-315.

Chapter Four: Chem ical Analysis of Bigleaf Maple Sap and Syrup

4.1 Introduction

Sugar maple sap has been tapped for syrup production in Eastern Canada for

centuries. Because of its economic importance in Eastern Canada, the composition of

sap and syrup produced from the sugar maple (Acer saccharum) has been extensively

described (Heiligmann et al. 2006). Maple syrup can also be made from most of the

13 species of the Acer genus in North America; however, tapping has only been

deemed economically feasible from the sugar maple (A. saccharum), the black maple

(Acer nigrum) and the red maple (Acer rubrum).

Syrup is also made from black walnut tree (Juglans nigra) sap (Ball 2007) and the

sap of paper birch (Betula papyrifera) and Alaska birch trees (B. neoalaskana) found

in Alaska, Canada, Russia and Scandinavia. Birch syrup has a distinctive flavor and

differs from sugar maple syrup, in that its sugar content is mainly fructose and

glucose rather than sucrose (Ball 2007). The sugar concentration in birch sap is

approximately half that of the sugar maple sap and, therefore, more sap is required to

produce birch syrup.

Bigleaf maple syrup is being differentiated from other maples for its unique, darker

colour and robust flavour (Backlund 2004). Sap colour and flavour is determined by

the type of sugars, the length and intensity of sap boiling, and the interaction of amino

72 acids and other organic acids (Heiligmann et al. 2006). However, these factors are

still not fully understood, due to the complexity of the chemical reactions in the sap

that give maple syrup its characteristic taste and flavour (Heiligmann et al. 2006).

Little is known about the nutrients and sugar types of the bigleaf maple sap.

Information about the composition of bigleaf maple sap and syrup is required by the

members of the Vancouver Island Sapsucker community to assist with production and

marketing of their products. Knowledge about the composition of bigleaf maple

syrup will help facilitate acceptance of bigleaf maple syrup and thus promote further

development of the syrup production industry on Vancouver Island and in British

Columbia.

This chapter reports upon my analysis of sap and syrup samples from local bigleaf

maple syrup producers on southern Vancouver Island. Total solids, carbohydrate

(sugar) content and nutrient compositions of sap and syrup produced from bigleaf

maple were measured, and the results compared to published data on the composition

of sugar maple. This research provides baseline information for sap harvesters, and is

used in the thesis conclusion to identify areas for further research.

4.2 Methods

Fifty-seven sap samples were collected from primary producers on Vancouver

Island throughout the 2006/2007 tapping season (Dec 6, 2006 to Mar 8, 2007). Sap

samples were collected from maple stands in the Cowichan Valley, Port Alberni, and

Nanaimo area. Table 7 summarizes the number of samples collected for this study.

Sap samples were stored in 40 ml snap-and-seal containers, frozen at -18 º C and

analyzed in the laboratory at the end of the season.

Table 7. Summary of sap samples collected during the 2006/2007 tapping season.

Decem ber January February March Port Alberni Area 2 13 6 Cowichan Area 5 11 1 2 Nanaim o Area 1 10 5 1

In addition to the above sap samples listed in Table 7, 10 —murky“ sap samples with

white flecks, which may not have been frozen promptly, were collected. These flecks

may be proteins, however, further analysis would have been required to determine

their nature. These samples were analyzed along with the 57 primary samples.

Eight syrup samples were analyzed in the study. The syrup samples were collected

from one producer located in Glenora, Cowichan Valley. The syrup was produced by

boiling down raw sap using a W aterloo —Lightening“ small wood fired evaporator,

with a 2‘ x 4‘ raised flue pan. The sap was fed into the evaporator from a storage

tank, with the syrup or concentrated sap drawn off the evaporator at about 50 º Brix

and brought to syrup with a W aterloo propane finisher.

All sap and syrup samples were analyzed at the Ministry of Forest and Range

Research Branch in Victoria, British Columbia. The following parameters were

included in the analysis: carbohydrates, including sucrose, glucose and fructose;

macronutrients, including calcium (Ca), magnesium (Mg), potassium (K),

phosphorous (P) and sulphur (S); micronutrients including zinc (Zn), boron (B),

74 copper (Cu), iron (Fe), manganese (Mn) and sodium (Na). In addition, samples were

analyzed for total solids and density.

Samples for the analysis were taken from sap and syrup samples that had been

thawed at room temperature and then promptly refrozen. The carbohydrate analysis

was completed using anion exchange high performance liquid chromatography

(HPLC, W aters 600 System) with a Restek Pinnacle II sugar separation column and a

410 differential refractometer detector. Samples were prepared by filtration through a

0.45 micron nylon membrane filter. Concentrations of the major carbohydrates found

in the maple sap and syrup samples (sucrose, glucose and fructose) were determined.

The mineral analysis was done on whole, unfiltered homogenized samples. Sap

samples were thoroughly mixed and a 5 ml aliquot dispensed into a microwave

digestion vessel. For the syrup samples, 0.5 g was used. The samples were

evaporated to dryness at 105 o C then digested by microwave-assisted, closed-vessel,

strong acid digestion (Questron QLab 6000). This was followed by Ion Coupled

Plasma (ICP) elemental analysis (Teledyne-Leeman "Prodigy").

Total dissolved and suspended solids in each syrup and sap sample were

determined by gravimetric analysis. Five ml of the raw sap was weighed and then

heated at 105 ºC for 24 hours. The samples were then cooled in a desiccation

chamber and reweighed to determine the total solids. The syrup samples were treated

similarly except that 5 g of sample was dried and a measured density value applied to

convert the residue to a weight/volume basis. The results were organized, analyzed

and graphed using Microsoft EXCEL.

4.3 Results and Discussion

4.3.1 Bigleaf Maple Sap Carbohydrates and Cations

Volume of sap flow and sap sugar content determine the final yield of syrup. The

total solids in the bigleaf maple sap throughout the entire season ranged between

0.5% to 2.9% with an average of 1.4% (Table 8). A study by Ruth et al. (1972) found

similar solids content of the bigleaf maple sap, with ranges between 1.0% to 2.6%

and a mean of 1.4%. This is comparable to the solids content of sugar maple sap,

which ranges between 1.0% and 5.4% and an average content of 2.0% to 2.5%

(Morselli & W halen 1980; Heiligmann et al. 2006,).

Table 8. Comparison of the total solids content of the bigleaf maple and sugar maple sap.

Total Solids Range (%) Average (%) Bigleaf Maple Sap 0.5-2.9 1.4 Sugar Maple Sap 1.0-5.4 2.0-2.5

In sugar maple sap, sugars comprise more than 98% of the solids. The remaining

2% is various other substances such as amino acids, minerals and salts, organic acids,

phenolic compounds and other components (Heiligmann et al. 2006). A sap sugar

content of 1% means that the sap contains 1 g of sugar per 100 g of sap (Taylor

1956). Thus, the estimated syrup yield can be calculated from the sugar content and

sap flow volume data.

Sucrose was the main carbohydrate found in the bigleaf maple sap (Table 9),

followed by fructose and glucose. There was a higher percentage of the invert sugar,

76 fructose and glucose, compared to the sugar maple sap (0.0% to 0.17%) (Heiligmann

et al. 2006).

Table 9. Average carbohydrate content of sap samples.

Bigleaf m aple Sap % Sucrose % Glucose % Fructose December 95.48 1.62 2.9 January 96.33 1.35 2.32 February 96.76 1.03 2.21 March 96.5 1.70 1.8

Different carbohydrates have different melting points (see Section 2.11). The

melting point for sucrose is 185-186 ºC. The melting point of fructose (103-105 °C)

is much lower than glucose (150 ºC). Because the percentage of fructose is higher

than glucose in the bigleaf maple sap, scorching during the syrup production process

could be an issue. Scorching can result in syrup with a burnt flavor. Therefore, sap

boiling temperatures should be monitored during the syrup production process.

Table 9 shows the composition of the —murky“ sap samples that were analyzed as

part of this study. The samples have considerable higher content of glucose and

fructose and lower sucrose concentrations compared to the primary —clear“ sap

samples analyzed. It is likely that the sucrose in the samples was converted to

glucose and fructose as these samples may have been outside in warm conditions for

an extended period of time. Many producers wait until they have a significant

volume of sap before making a sap collection and these samples may have been from

sap that was sitting around for a few days. In addition, there appears to be additional

solids in these samples as the total solids do not add up to 100%. These solids may

77 be proteins, amino acids, minerals or different carbohydrates. Further analysis is

required to determine the composition of these solids.

Table 10. Average carbohydrate content of murky sap samples.

Num ber of m urky sam ples % Sucrose % Glucose % Fructose 10 50 16.6 24.2

Scorching could be an issue for the murky samples because of the high levels of

fructose and glucose. The lower boiling point of these carbohydrates could burn the

syrup and alter the taste. Maintaining a steady heat can be challenging especially

when wood is used to heat the evaporator. It was expected that the levels of invert

sugar would be higher later on in the season due to the warmer weather and higher

enzymatic activity on the sugars, however, this was not observed. In addition, other

carbohydrates may be present in small amounts in the bigleaf maple sap as this has

also been observed in the sugar maple.

There was considerable variability in the sugar content from the selection of bigleaf

maple trees, which is also well documented in the literature concerning sugar maple

(Jones et al. 1903, Taylor 1956, Blum 1973). Researchers have attempted to link

physical characteristics of a stand with the sap sugar content. However, these results

tend to be imprecise (W ilmont et al. 1995). Laing and Howard (1990) demonstrated

that sap sugar content of an individual maple stem is influenced by a combination of

environmental and genetic factors. It is recognized that sap sugar content of a tree is

not a constant value but varies with season, day to day and with time of day

(Heiligmann et al. 2006). The sugar maple is open-pollinated and therefore

genetically variable. However, open grown mature maple trees tend to produce

78 sweeter sap than forest grown maple stems (Moore et al. 1951) which was observed

by many of the bigleaf maple producers.

Table 11 shows a summary of results from the bigleaf maple sap analysis.

Minerals such as calcium, potassium and magnesium were found in the highest

concentration. Calcium was the highest mineral with a mean concentration of 282

ppm followed by potassium with a mean of 202 ppm and 18.8 ppm for magnesium.

Minerals such as boron, copper, iron, manganese, sodium, sulphur, and zinc were

present but in concentrations less than 3.0 ppm.

Table 11. Range of the carbohydrate content (%) and mineral concentration (ppm) in the bigleaf maple sap samples.

Bigleaf maple sap Range Mean Standard Error Total Solids (% ) .5-2.9 1.40 0.07 Carbohydrates Sucrose (%) 88-98.5 93.10 3.32 Glucose (%) 0.6-7.7 4.10 1.04 Fructose (%) 0.2-4.1 6.10 1.57 Minerals (ppm) Boron (B) 0-.04 0.04 0.00 Calcium (Ca) 36-10684 282.00 153.90 Copper (Cu) .01-2.12 0.06 0.03 Iron (Fe) .15-1.12 0.28 0.02 Potassium (K) 62-405 202.00 8.40 Magnesium (Mg) 5-30.5 18.80 0.84 Manganese (Mn) .25-23.77 2.20 0.38 Sodium (Na) <.01-2.85 0.59 0.18 Phosphorous (P) 1.12-30 6.07 0.60 Sulpur (S) 0.47-12.54 2.52 0.29 Zinc (Zn) .08-1.2 0.47 0.02

The concentrations of the three major cations potassium, calcium and magnesium,

are compared to published data on sugar maple composition (Marvin & Greene

1959). Figure 22 shows that the concentrations of the three major cations are higher

in the bigleaf maple sap than the sugar maple sap. This may be due to the fact that

bigleaf maple absorbs and retains large quantities of nutrients during its growth

period however this is just a speculation. These nutrients that are absorbed by the

maple are later returned to the surrounding site as decomposing leaf litter thus

continuing the cycling of nutrients (Peterson 1999).

Comparison of the Mean Cation concentrations (ppm) in the bigleaf and sugar maple sap

) 300 m p p

( 250

o 200 i t Bigleaf maple sap a r

t 150

n Sugar maple sap e 100 c n

o 50 C 0 Potassium Calcium Magnesium Cation

Figure 22. Mean concentrations (ppm) of potassium, calcium and magnesium in the bigleaf and sugar maple sap.

4.3.2 Bigleaf Maple Syrup Carbohydrates and Cations

As in sugar maple sap, sucrose is the dominant sugar in bigleaf maple sap.

However, the percentage of invert sugars (glucose and fructose) is higher in bigleaf maple syrup than its Eastern counterpart (Heligimann et al. 2006). This is likely a

result of the warmer climate on the W est Coast, which increases enzymatic activity

and thereby the rate of sucrose conversion to invert sugars (Morselli & W halen 1991).

This may contribute to the darker colour and taste of the bigleaf maple syrup.

Although darker colour and taste are considered to be a lower grade in the Easter

Canada, it is often more desirable for consumers. Research conducted by Driscoll

(1998) states that consumers prefer the darker syrup in blind taste tests. This was

evident at the blind taste tests at the bigleaf maple festival in Duncan, Vancouver

Island, where the darker syrup won the peoples‘ choice award. Table 12 shows a

summary of results from the bigleaf maple syrup analysis along with the typical

composition of sugar maple syrup. Although the sample size for the bigleaf maple

syrup was relatively small, it provides baseline information on the carbohydrate and

nutrient content. The information on the sugar maple syrup range and mean, is a

compilation of different research studies (Morselli 1975, Stuckel & Low 1996,

Dumont 1996, Perkins (unpublished), van den Berg, Perkins and Isselhardt

(unpublished) and is summarized in Heiligmann et al. (2006).

The % of total solids for the bigleaf maple syrup ranged between 62% and 70%

which is comparable to the typical range of the sugar maple, at 62% to 69.5%.

Sucrose was the predominant sugar found in the bigleaf maple syrup, with a range

between 53% to 61%. This is slightly lower than in sugar maple syrup. The bigleaf

maple syrup has a higher percentage of glucose and fructose, with means of 1% and

2% respectively, as compared to 0.4% and 0.5%, respectively, for the sugar maple.

This could account for the darker colour and flavour of the bigleaf maple syrup.

Table 12. Range of the carbohydrate (%) and mineral concentrations (ppm). Bigleaf maple syrup Sugar maple syrup Sugar maple syrup Bigleaf maple syrup Range Mean Std Error Typical Range* Typical Mean * Total Solids (%) 62-70 66.00 0.90 62-69.5 65.00 Carbohydrates Sucrose (%) 53-61 57.00 0.80 42.3-75.6 66.00 Glucose (%) 0-3 1.00 0.40 0-9.6 0.40 Fructose (%) 1.0-3 2.00 0.20 0-6.8 0.50 Minerals and Metals (ppm) Boron (B) 1.53-2.40 1.86 0.11 .01-3 0.20 Calcium (Ca) 805.91-2234.37 1393.26 175.36 183-2800 911.00 Copper (Cu) .26-3.42 1.35 0.43 0-8 1.20 Iron (Fe) .68-1.34 1.15 0.10 0-36 10.00 Potassium (K) 3984.14-5105.78 4685.49 146.43 541-4031 2283.00 Magnesium (Mg) 271.33-486.27 390.21 24.93 0-575 177.00 Manganese (Mn) 2.91-17.16 10.75 1.86 0-252 39.80 Sodium (Na) 6.52-187.69 42.90 21.02 0-492 36.00 Phosphorous (P) 5.24-26.02 10.35 2.55 2-235 37.00 Sulpur (S) 32.56-96.14 58.91 7.20 .01-100 18.20 Zinc (Zn) 2.12-6.52 4.26 0.52 0-130 22.00

*Sugar maple typical range and means from Heiligmann et al. (2006).

The most predominant minerals in the bigleaf maple syrup are potassium, calcium and magnesium as was found with the bigleaf maple sap (Figure 23). As expected, the minerals were found in much higher concentrations in the syrup compared to the sap. Because these minerals are non-volatile, they concentrate as the sap is processed into syrup (Ball 2007). Potassium was found at the highest concentration with concentrations ranging from 3984 to 4984 ppm, followed by calcium and magnesium.

Comparison of the Mean Cation concentrations (ppm) in the bigleaf and sugar maple syrup 5000

) 4500 m

p 4000 p (

3500 n

o Bigleaf maple syrup i 3000 t a

r 2500

t Sugar maple syrup n

e 2000 c

n 1500 o

C 1000 500 0 Potassium Calcium Magnesium Cation

Figure 23. Comparison of the mean concentration (ppm) of potassium, calcium and magnesium found in the bigleaf and sugar maple syrup.

A layer of sugar sand is often found in the finished bigleaf maple syrup. As sap is evaporated into syrup, solubility of various salts is high, however when the syrup is cooled, the solubility of certain salts drops below the saturation limit and crystals precipitate. These crystals are called sugar sand and are mostly composed of small sugar crystals and calcium malate (Ball 2007). The calcium malate results from high calcium and malic acid in the syrup and is one of the least soluble salts in the syrup.

The relative concentration of calcium in the bigleaf maple sap is greater than in the finished syrup. Therefore, it is likely that calcium precipitated out as sugar sand. In eastern Canada, sugar sand is required to be filtered from the syrup before it is packaged and marketed for aesthetic reasons (Ball 2007).

4.4 Lim itations

The current study represents the first published data on the sugar and nutrient

composition of bigleaf maple sap and syrup. A complete characterization of the sap

and syrup characteristics would require analysis for amino acids, organic acids,

crystallized sugar, and proteins, which all contribute to the colour and taste of the sap

and syrup. A larger number of sap and syrup samples over several seasons would

provide a more accurate analysis of the sugars and nutrients. In addition, this project

encompasses a participatory research method and the sap samples were collected

from a variety of different producers on Vancouver Island. Thus, the sap may have

been left outside for extended periods of time before being frozen. However, this

provides a realistic characterization of the sap sugar and nutrient content being used

by local producers on Vancouver Island.

4.5 Conclusions

The bigleaf maple tapping season yielded sap with an average total solids content

ranging from 0.5% to 2.9% with a mean of 1.4%. The percentage of total solids is

lower than that typically found in sugar maple sap (2.0% to 2.5%). Therefore, a

greater quantity of sap is required to produce an equivalent volume of finished syrup.

On average, 60 litres of bigleaf maple sap are required to produce 1 litre of finished

syrup.

There was considerable variability in the total solids content of the individual sap samples. A similar variability is found in the sugar maple sap. Despite extensive within-season variation, trees with the highest sugar concentration maintain their relative position in the population and always tend to be the sweetest tree (Taylor

1956). This is important for forest managers to recognize when determining which trees are suitable for tapping.

As with the sugar maple, the dominant sugar found in the bigleaf maple sap and syrup was sucrose. However, the bigleaf maple sap and syrup has a higher percentage of fructose and glucose. This is likely due to the warmer climate found in the W est, and the higher activity of microorganisms on the sap sugars. If lighter syrup is desired, producers should keep the sap cool and boil down the sap promptly, in order to reduce the percentage of invert sugar. W hen the evaporating period is reduced, lighter coloured syrup tends to be produced, as with the sugar maple (Taylor

1956).

The analysis of the bigleaf sap and syrup cations determined that there was a high concentration of calcium, potassium and magnesium present compared to the sugar maple. Calcium was found in the highest concentration in the bigleaf maple sap and potassium was found in highest concentration in the syrup. It is likely that some of the calcium was precipitated out of the syrup into sugar sand.

4.6 References

Backlund, G. and K. Backlund. 2004. Bigleaf Sugaring: Tapping the Western Maple. Backwoods Forest Management, Ladysmith, British Columbia.

Ball, D.W . 2007. The chemical composition of maple syrup. Journal of Chemical Education. 84 (10): 1647-1649.

Blum, B.M. 1973. Relation of sap and sugar yields to physical characteristics of sugar maple trees. Forest Science. 19 (3): 175-179.

Campbell, N.A. 1993. Biology 3rd edition. The Benjamin/Cummings Publishing Co. Inc., Redwood City, California. 1190 p.

Driscoll, M. 1998. Seeking —real“ maple syrup flavor. Cooks Illustrated. March and April: 26-27.

Heiligmann, R.B., M.R., Koelling, and T.D. Perkins (eds.). 2006. North American Maple Syrup Producers Manual (2nd ed.). The Ohio State University: For Sale Publication, United States. 329 p.

Jones, C.H., A.W . Edson and W .J. Morse. 1903. The maple sap flow. Vermont Agricultural Experiment Station Bulletin. 103: 184 p.

Laing, F.L. and D.B. Howard. 1990. Sap sweetness consistency vs. growth rates in young sugar maples. Northern Journal of Applied Forestry. 7 (1): 5-9.

Marvin, J.W . and M.T. Greene. 1959. Some factors affecting the yield from maple tapholes. Vermont Agricultural Experiment Station Bulletin. 611: 1-21.

Marvin, J.W .M., Morselli., and F.M. Laing. 1967. A correlation between sugar concentration and volume yields in sugar maple-an 18-year study. Forest Science. 13 (4): 346-351.

Moore, H.R., W .R. Anderson and R.H. Baker. 1951. Ohio maple syrup-some factors influencing production. Ohio Agricultural Experiment Station Research Bulletin. 718: 1-53.

Morselli, M.F. and M.L. W halen. 1980. Invert sugar analysis of maple syrup and sap. Maple Syrup Digest. 20 (1): 22-23.

Morselli, M.F. and M.L. W halen. 1991. Asceptic tapping of sugar maple (Acer saccharum) results in light grade syrup. Canadian Journal of Forest Research. 21 (3): 999-1005.

Peterson, K.D. 1999. The Ecology and Silviculture of Bigleaf Maple. Extension Note 33. Ministry of Forest Research Program. Victoria, British Columbia.

Ruth, R.H. J.C. Underwood, C.E. Smith and H.Y. Yang. 1972. Maple sirup production from bigleaf maple-Note PNW -181. United States Department of Agriculture Forest Service, Portland, Oregon.

Stevenson, D.D. and R.A. Bartoo. 1940. Comparison of the sugar per cent of sap in maple trees growing in open and dense groves. Penn State Forestry School. Resource Paper 1.

Stuckel, J.G. and N. H. Low. 1996. The chemical composition of 80 pure maple syrup samples produced in North America. Forest Research International. 29 (3-4): 373-379.

Taylor, F.H. 1956. Variation in sugar content of maple sap. Vermont Agricultural Experiment Station Bulletin 587. Vermont, United States.

W ilmont, T.R., M. Isselhardt, and T. Perkins. 1995. Vigor and nutrition vs. sap sugar concentration in sugar maples. Northern Journal of Applied Forestry. 12 (4): 156-162.

Chapter Five: Sum m ary

5.1 Sum m ary of Research

The majority of the bigleaf maple sap flow occurred over a 6 week period, starting

at the end of December until early February. Bigleaf maple sap flows were

intermittent until the beginning of March, when the buds burst. Fluctuations in air

temperature, above and below zero, influenced sap flow as described in section 3.3.1.

The sap flow was highly variable between plots, with seasonal sap flow totals ranging

from 93.5 litres to 839.4 litres. Plots with larger dbh trees had higher flows, although

the difference was not statistically significant. Sap flow was significantly different in

edge plots than in forested non-edge plots. Plots located on sandier soils had higher

sap flow, although not statistically significant. The single stem plots produced more

sap than the coppice plots. A multi-variant regression model was employed to

describe this relationship between sap flow and other independent variables. The

model (r2 = 0.68) explained that 68% of the variation in sap flow in every 4 day

period can be predicted by the temperature variable and the sampling effort.

The carbohydrate concentration of the bigleaf maple sap and syrup consists mainly

of sucrose with a minor component of fructose and glucose. The levels of fructose

and glucose are approximately twice the concentration found in the average sugar

maple saps possibly contributing to the different flavor of the bigleaf maple syrup.

The total solids of the individual samples varied greatly, with ranges between 0.5 to 9

%. This variation is also found in the sugar maple. The average sugar content of the

88 bigleaf maple is 1.4%. Approximately, 60 litres of bigleaf maple sap makes 1 litre of

syrup.

The highest concentrations of cations in the bigleaf maple sap were K, Ca and Mg,

respectively. This result was similar to sugar maple sap although the concentrations

of the three major cations are much higher in bigleaf maple sap. The most

predominant minerals in bigleaf maple syrup are K, Mg and Ca, as found with bigleaf

maple sap. The minerals were found in much higher concentrations in the syrup

compared to the sap and were higher than in sugar maple syrup. The concentration of

calcium was lower in bigleaf maple syrup compared to the sap. The calcium may

have precipitated out as sugar sand during the evaporation process.

5.2 Social Benefits of Syrup Production

Tapping bigleaf maple sap is a novel activity initiated by local community

members who seek to diversify their local forest economy. In addition to the

biological aspects of this non-timber resource, the social and economic benefits of

this activity are described in the following sections (5.2-5.3).

Sugar maple production in the eastern United States and Canada herald the

beginning of spring. In many of these areas, communities plan events around the

maple syrup harvest, which is recognized for its benefits of strengthening community

ties (Hinrichs 1998). For displaced or marginalized rural residents, an identity as a

syrup producer can provide a social identity during difficult times (Hinrichs 1998).

From a cultural perspective, the eastern maple syrup industry represents a positive

work experience that unites families and communities, connects individuals to the

89 land, and provides a sense of history (W hitney & Upmeyer 2004). This nostalgic

time of year is a time of visiting and socializing, and a celebration of the coming of

spring (Shanley et al. 2002). Activities such as local sugaring festivals help brighten

the dreary days of winter.

Although the bigleaf maple tapping industry is still in an early stage of growth,

many events and activities have shown its positive impacts in communities on

Vancouver Island. In 2004, the Vancouver Island maple project promoted this

cottage industry by hosting four workshops through the Master W oodland Managers

Program to more than 85 private landowners, forest managers and provincial

representatives (Macy 2004). Gary Backlund, a woodlot owner on Vancouver Island,

was inspired by this workshop and decided to tap trees on his woodlot. He built a

sugarshack and then wrote an instructional bigleaf maple tapping guidebook

(Backlund & Backlund 2004). The Backlunds conduct presentations, tours and

workshops at their woodlot, educational institutes and other interested venues. Since

2003, the number of people tapping on Vancouver Island has doubled each season

(Backlund & Backlund 2004). In addition, several more evaporators were purchased

by individual landowners on Vancouver Island and the Gulf Islands and tapping

supplies are now available for purchase at some hardware stores. A Vancouver Island

maple email group termed the —sapsuckers“ was established with a distribution list of

more than 130 individuals. This has created an online forum for tappers to discuss

variation in sap flows and topics related to syrup production.

Lawrence Lampson from Glenora Farms in the Cowichan Valley has become

interested in this activity. Through a series of fundraisers, he was able to purchase a

90 commercial sized evaporator for his sugarbush and has been making syrup and

conducting educational tours at his farm. Lampson has generated interest in tapping

bigleaf maple throughout the Cowichan Valley, with the hopes of increasing the sap

supply for his custom syrup making operation. His enthusiasm for this activity has

been met with positive feedback and active participation by members of this

community.

Figure 24. Lawrence Lampson, at Glenora Farms, conducting an educational tour of the sugarshack.

A bigleaf maple syrup festival was held on February 2, 2008 and was an

overwhelming success. The festival was open to all members of the community and

1400 people attended the event (Scott, The Times Colonist, February 24, 2008).

Local producers brought samples of their maple syrup for community members to try.

There was local music, syrup tasting contests, tapping demonstrations, an on-site

evaporator and educational tours. The event brought together a diverse mix of the

community and showed the enthusiasm of the public toward this activity.

The media has shown interest in this activity. There were several newspapers,

radio and television interviews conducted on the bigleaf maple research (Table 13).

Table 13. List of interviews conducted during this research project.

Newspaper, Radio, Television Date Alberni Valley Times 30-Nov-06 Alberni Vally Times 04-Dec-06 Alberni Valley News 08-Dec-06 W est Coaster Online Paper 01-Dec-06 W estern Division of the Canadian Association of Geographers Fall 2006 CBC Morning Show Interview 01-Dec-06 Shaw Cable Television Interview 21-Dec-06 Agroforestry Update Mar-07 Victoria News 19-Oct-07 Times Colonist 24-Feb-08

Overall, tapping the maple is a positive social activity that encourages people to spend time being active during the cold winter months. By being involved in the tapping community, people can enjoy the benefits of being part of a larger social

network, which encourages a sense of emotional, mental and physical well being.

5.3 Tapping into the Econom ic Benefits

Maple syrup production in Canada is generally associated with sugar maple trees

found in Eastern Canada. Canada is the largest maple syrup producer in the world,

with 82% of the world‘s production. Today maple syrup is the basis of a multi- million dollar industry in North America, with the majority of production in Ontario

and Quebec. An estimated 33,745 metric tonnes of maple syrup, valued at $177.9

92 million, was produced in 2006 (Agriculture and Agri-Food Canada 2007). Sugar

maple syrup is one of the few NTFPs that can exceed the value of timber on a per-

hectare basis (Pierce 2002).

Historically, sugar maple tapping, with its seasonal flows and limited geographic

distribution provided small rural farmers with crucial income before the spring

planting season. Syrup enterprises tended to be small scale activities located on farms

or woodlots. The activity remained small due to its seasonality and the labour

involved for a tapping operation. Quantity and quality of sap yield varied from year

to year, making production unpredictable; therefore labour was largely limited to

extended family members (Hinrichs 1998).

Today, eastern syrup producers are attracted to this activity because of the

economic contribution and the experiential and cultural rewards of production itself

(Hinrichs 1998). The seasonality of this activity encourages land owners to

productively use their land, diversify their work activities and generate additional

income during the winter months. For many producers, maple sugaring provides

supplemental cash income (Shanley et al. 2002).

As the bigleaf maple syrup cottage industry continues to grow, it is important to

assess its economic potential. This activity could provide a supplemental income for

farmers, private forest landowners and entrepreneurs in the Coastal forest region

where bigleaf maple is found. Many of the bigleaf maple tappers are retired and

interested in a home based activity during the winter. In a study by Hinrichs (1998),

the importance of syrup production revolved less around absolute revenue than

around the contribution such enterprises provide to manage risk, deal with

93 seasonality, define an identity and engage in the community. Maple syrup production

can also assist rural landowners in achieving farm status and the associated tax

breaks.

Eastern maple cooperatives have been formed to assist with marketing and sales of

the product. By working together, producers have the ability to obtain higher prices

for syrup and influence the industry in their region. Members of the cooperative pay

a membership fee that allows it to assist with product expansion, research and other

relevant activities (Heiligmann et al. 2006). Forming a cooperative may be a feasible

option for the bigleaf maple syrup community if it continues to grow.

Because of its limited geographic range, the bigleaf maple syrup can be marketed

for its distinctive W est Coast flavour. Bigleaf maple syrup can be considered a 100%

natural, organic condiment, produced in a sustainable manner. This high end niche

product could be suitable for specialty markets, tourist shops, hotels, and fine dining

restaurants. It could also be marketed as a —green“ product for the health- and

environmentally- conscious consumer. The syrup could capture a niche in the

—organic“, —slow food“ and —100 mile diet“ movements. Organic certification is

distributed through the Island Organic Producers Association. There are specific

standards for maple products and the process takes approximately three months

(Canadian General Standards Board 2006). The slow food movement has also

become very popular in recent years. Slow food is a non-profit organization that was

created to counteract fast food and is committed to exploring and preserving local,

wild food products. Bigleaf maple products would likely be acceptable for the Slow

Food Arc; however, eligibility takes a long time to process. The 100 mile diet is

94 focused on eating local foods grown within a 100 mile radius. First started off as an

experiment and has now turned into a movement (Smith & MacKinnon 2007). On

Vancouver Island, honey is the only sugar source available; however, people on strict

vegan diets will not eat honey. Bigleaf maple sap and syrup could be utilized as a

locally produced sugar source found within the 100 mile range.

Maple tapping has the potential to grow as a tourism activity in a season when

other forest related activities have slowed down. It also has the potential to emerge as

an educational tool for elementary school children and other interested groups in

timber dependent communities. Combining the sales of syrup with tours and syrup

tastings could provide a seasonal income.

There may be potential to market the bigleaf maple raw sap as a tonic, as

experienced with the birch syrup. Birch sap is part of the traditional medicine in

many northern countries such as Japan, China, Russia and Finland and is used as a

health tonic (Terazawa 1995; Maher 2005). Birch sap is a traditional medicine that

treats a variety of different ailments such as hypertension, urinary problems, gout,

decreased work capacity, gastritis and scurvy (Terazawa 1995; Maher 2005).

Marketing the bigleaf maple sap as a health tonic could eliminate the time consuming

process of boiling down the sap to syrup. W hile there is no universally accepted

definition for nutraceutical; however, a lay definition is —a foodstuff that provides

health benefits in addition to its basic nutritional value“ (Merriam-W ebster 2005).

Thus, bigleaf maple sap could potentially be marketed as a nutraceutical. More information will be required on the nutrient content and associated health benefits of

bigleaf maple sap and syrup before marketing any products as a nutraceutical.

Additionally, recent research claims that maple sap could be marketed as a

potential green products source. Researchers claim that the sugar maple sap could be

used as a natural, biodegradable polymer that could reduce our reliance on fossil fuel-

based plastics (CBC News Radio, March 15, 2007). This new use may provide an

economic boost to this seasonal cottage industry.

5.4 Future Research and Forest Managem ent Recom m endations

As a master‘s project, this research had limitations on the scope and length of the

study in order to remain within the financial constraints and a realistic timeline.

Since this is the first research project on bigleaf maple tapping, there are many avenues for future research. Sustainable management requires a greater understanding of the potential growth of the industry. An improved inventory of

bigleaf maple on Vancouver Island would be advantageous for future research and

forest management. W ithout baseline inventories and management, it is difficult to

determine whether commercial endeavors within the non-timber forest products

sector would not impede conservation efforts, recreation, subsistence use or cultural

access (Cocksedge 2006). Determining land ownership and then delineating areas

suitable for biological conservation, timber management and maple tapping could

assist in managing for the bigleaf maple‘s multiple uses. Permitting or leasing system

for harvesters on both crown and private land could also be researched.

To understand the influence of temperature and other independent factors on sap

yield, a multiple year study is necessary. Plots could be replicated to see if strong or

96 weak correlations exist between sap flow and temperature fluctuations. Additional

plots could be monitored to increase the data set and the geographic range.

In addition, the sugar content could be measured for the plots to assess if there is a relationship between high sugar content and sap yield. Additional sap samples could

be analyzed for seasonal trends in sugar content and nutrients. Further research on

the concentration of amino acids, crystallized sugar and proteins in both the sap and

the syrup, is required to determine the influence of these factors on the taste and

colour. In addition, a longer study could assess the ecological impacts of sap harvest.

Researchers and forest managers should continue to work together with local

harvesters to design suitable management practices that ensure a sustainable

approach.

Research is required to improve the understanding of how bigleaf maple grows and

responds to various treatments. Silviculture treatments, such as thinning, cutting and

tree planting, could improve the growth and productivity of maple stands. Field trials

could be conducted to assess the regeneration of the bigleaf maple seedlings, in order

to determine how many species per hectare to plant (Peterson 1999). In addition,

genetic research on sugar maple suggests that the sap sugar content of planted

seedlings can be controlled through selection (Heiligmann et al. 2006). This may be

of interest to landowners who would like to reforest their land with maple seedlings

for sap production.

Eastern sugarbushes are managed primarily for sap production, although some

landowners manage their stands for both sap and timber production. The sweetness

and the sap flow of the trees vary greatly, and landowners therefore manage their

97 stands to favor the best producing trees (Shanley et al. 2002). In most cases, species

other than sugar maple are removed and the sugarbush thinned to encourage growth

of the remaining top producing trees. Eastern producers often conduct an

intermediate cut to remove dead branches or defective trees, which increases the

growth of the remaining trees and is the management activity that is most effective to

increase sap production (Heiligmann et al. 2006). The cut wood can be used to heat

the evaporator or sold as firewood. On Vancouver Island, maple stands are largely

unmanaged. However, bigleaf maple responds positively to density management by

increasing its diameter growth (Comeau et al. 1999). Thinning and pruning maple

stands could increase the productivity and growth of existing stems. In many cases,

coppices are left to grow and consist of 10-20 sprouts. Thinning these coppices to 3-5

stems could improve the sugaring potential as well improve the wood quality of the

remaining stems. Further research is required to determine the best silviculture

strategy to optimize both the single stem and coppice stands.

Research could be conducted on the value added opportunities of the bigleaf maple

syrup. Determining suitable products, market opportunities and the ability to sell

products on the internet could be useful for the economic development of this

resource. Assessing goals and hurdles for product development, such as proper

labeling and export markets, are important factors that will affect the economic

feasibility of this NTFP. Determining the feasibility of forming a maple cooperative

on Vancouver Island, could also be an area of interest. All in all, there are many

potential socio-economic opportunities that could be explored with this emerging

non-timber resource.

5.5 References

Agriculture and Agri-Food Canada. 2007. Canadian Maple Products: Situations and Trends 2006-2007. Available online at http://www4.agr.gc.ca/resources/prod/doc/misb/hort/sit/pdf/maple2006- 07_e.pdf; last accessed on November 15, 2007.

Backlund, G. and K. Backlund. 2004. Bigleaf Sugaring: Tapping the Western Maple. Backwoods Forest Management, Ladysmith, British Columbia. 98 p.

Canadian General Standards Board. 2006. Organic Production Systems. General Principals and Management Standards. Available on line at http://www.tpsgc-pwgsc.gc.ca/cgsb/on_the_net/organic/032_0310_2006- e.pdf; last accessed on M arch 1, 2008.

CBC News Radio in Depth. 2007. Maple Sap Tapped as a Potential Green Resource. Available online at http://www.cbc.ca/news/background/science/maple- sap.html: last accessed on December 9, 2007.

Cocksedge, W endy. 2006. Incorporating Non-timber Forest Products into Sustainable Forest Management. An Overview for Forest Managers. Available online at http://cntr.royalroads.ca/files- cntr/Incorporating%20NTFPs.pdf: last accessed on February 26, 2008. Royal Roads University, Victoria, British Columbia. 232 p.

Comeau, P.G., K.D., Thomas, E.B. Peterson, and M.N. Peterson. 1999. Bigleaf Maple Managers‘ Handbook for British Columbia. British Columbia Ministry of Forests, Victoria. 105 p.

Heiligmann, R.B., M.R., Koelling, and T.D. Perkins (eds.). 2006. North American Maple Syrup Producers Manual (2nd ed.). Ohio State University: For Sale Publication. 329 p.

Hinrichs, C.C. 1998. Sideline and lifeline: the cultural economy of maple syrup production. Rural Sociology. 63 (4): 507-532.

Macy, Harold. 2004. Sweet success for new Vancouver Island enterprise. Ecoforestry. Spring: 27-28.

Maher, K.A. 2005. Production and Quality of Spring Sap from Alaskan birch (Betula neoalaskana Sargent) in Interior Alaska. Unpublished MSc. Thesis, University of Alaska Fairbanks, Fairbanks, Alaska. 76 p.

Merriam-W ebster. 2007. Merriam-W ebster Online. Available online at http://www.m-w.com/dictionary/nutraceutical; last accessed on December 9, 2007.

Peterson, K.D. 1999. The ecology and silviculture of Bigleaf maple: Extension Note 33. Ministry of Forest Research Program,Victoria, British Columbia.

Pierce, A.R. Maple Syrup (Acer saccharum). In: Shanley, P., A.R. Pierce, S.A. Liard, A. Guillen (eds). Tapping the green market: certification and management of non-timber forest products. Earthscan Publication, London. 456 p.

Scott, C. February 14, 2008. Festival turnout delights planners. The Times Colonist. p.D12.

Shanley P., A. Pierce, S.A.Laird, and A.Guillen (eds). 2002. Tapping the green market. Certification and management of non-timber forest products. Earthscan Publications Ltd, London. 456 p.

Smith, A. and J.B. MacKinnon. 2007. The 100 Mile Diet. A Year of Local Eating. Random House Canada, Toronto. 272 p.

Terazawa, M. 1995. Shirakamba Birch, Splendid Forest Biomass–Potential of living tree tissues. In: Terazawa, M., C.A. McLeod, Y. Tamai (eds.). Tree Sap Proceedings of the 1st International Symposium on Sap Utilization (ISSU). University Press, Bifuko, Japan. 7-12 p.

W hitney, G.G. and M.M. Upmeyer. 2004. Sweet trees, sour circumstances: the long search for sustainability in the North American maple products industry. Forest Ecology and Management 200 (1-3): 313-333.

100

Appendix 1

Section 104 of the Forest Practices Code Act, which refers to botanical forest products: 104. Buying of botanical forest products 104. Unless a person holds a valid botanical forest product buyer's licence, the person must not, as part of a commercial enterprise, buy a botanical forest product from a person, or otherwise engage in trade concerning a botanical forest product with a person who harvested the botanical forest product if it

(a) was harvested from Crown land in a Provincial forest or Crown range, and (b) is designated in a regulation for the purposes of this section.

216. Botanical forest products 216. (1) In this section, "licence" means a botanical forest product buyer's licence referred to in section 104.

(2) The Lieutenant Governor in Council may make regulations respecting the following: (a) establishing a licencing scheme for the purposes of section 104; (b) issuing, amending, renewing, suspending or cancelling licences; (c) applications for licences; (d) fees for licences and applications; (e) inspectors and inspections for the purposes of enforcing licencing; (f) appeals (B.C. Government, Forest Practices Code of British Columbia Act)

101

Vita

Surname: Bruce Given Names: Deirdre

Place of Birth: Beverly, Yorkshire, England

Educational Institutions Attended: University of Victoria 2005 to 2008 University of British Columbia 1999 to 2003

Degrees Awarded: BSc. University of British Columbia 2003

Honours and Awards: Pacific Forestry Centre Graduate Student Award 2005-2007 Agroforestry Industry Development Initiative 2006-2008 Oscar Soderman Memorial Scholarship 2002 Charles and Jane Banks Scholarship 2002 W illiam John Splan Scholarship 2001 W est Fraser Timber Scholarship in Forestry 2001

102