WESTERN HEMLOCK–DOUGLAS-FIR/ELECTRIFIED CAT’S-TAIL MOSS heterophylla–Pseudotsuga menziesii/Rhytidiadelphus triquetrus Original prepared by J. Pojar, S. Flynn, and C. Cadrin

Plant Community Distribution Information Global Unknown. Description This forest community has a canopy composed primarily of western hemlock (Tsuga heterophylla) In British Columbia, this community occurs in the and Douglas-fir (Pseudotsuga menziesii), with a lesser drainages of the lower Fraser River east and north of component of western redcedar (). The Chilliwack, and in the eastern portion of the Coast/ shrub layer is rather sparse and not vigorous, with Cascade Mountains from upper Harrison Lake to low cover of falsebox (Paxistima myrsinites), red the Homathko River. It also occurs in submaritime huckleberry (Vaccinium parvifolium), black and subcontinental areas north of the head of huckleberry (Vaccinium membranaceum), baldhip Knight Inlet, especially in the lower Klinaklini, Bella rose (Rosa gymnocarpa), and sometimes dull Coola, Talchako, and Dean valleys. Oregon-grape (). Twinflower Forest regions and districts (Linnaea borealis), queen’s cup (), Coast: Chilliwack, North Island, Squamish, and prince’s pine (Chimaphila umbellata) dominate Sunshine Coast the moderately diverse herb layer. Other common Southern Interior: , Chilcotin herbs include rattlesnake-plantain (Goodyera oblongifolia), pink wintergreen (Pyrola asarifolia), Ecoprovinces and ecosections one-sided wintergreen (Orthilia secunda), sword fern CEI: WCR (Polystichum munitum), and bracken fern (Pteridium COM: CPR, EPR, NPR, SPR aquilinum). The moss layer is dominated by step SOI: LPR moss (Hylocomium splendens), pipecleaner moss (Rhytidiopsis robusta), electrified cat’s-tail moss Biogeoclimatic unit (Rhytidiadelphus triquetrus), and red-stemmed CWH: ds1/01, ds2/01 feathermoss (Pleurozium schreberi). See Green and Klinka (1994). Broad ecosystem unit CW Zonal sites in the CWHds1. These forests occur mostly on middle slopes and higher terraces, on a Elevation variety of surficial deposits and on moderately well- Near sea level to 650 m drained soils with a range of textures, but tending to coarse-loamy rather than fine-loamy. Sites have Community Characteristics medium to poor nutrient regime and fresh to Structural stage somewhat dry soil moisture (relative within 6: mature forest subzone). 7: old forest

1 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 1 2 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Natural disturbance regime represents the largest area, proportionally, of all ecosystems within the subzone. However, this plant Infrequent stand-initiating events (NDT2) (MOF community has been heavily logged over much of its and MELP 1995), primarily (perhaps every range, and continues to be logged. Urban and 200–300 years, on average) and windthrow, agricultural developments have also impacted this sometimes snow avalanches and landslides. plant community. Timber harvesting of remaining Occasional direct mortality of individual or small patches of old and mature forest will continue, as groups of due to defoliating insects and root will localized urban development. Large old or rots, or indirect mortality via predisposition of mature, high quality occurrences are now rare. attacked trees to blowdown (see Pojar et al. 1999). Gap dynamics prevail in old forests. Threats Fragility Primarily threatened by forest harvesting and the Low to moderate. Soils typically are deep, somewhat resulting loss and fragmentation of sizeable, old, coarse-textured with a medium to poor nutrient high quality occurrences. Agricultural, rural, and regime. This plant community sometimes occurs on urban development (Fraser Valley, Pemberton Valley, unstable landforms, and could be susceptible to Bella Coola Valley) have also reduced the occurrence mass movements, especially those triggered by of this plant community. activity such as road building. It should also The greatly diminished connectivity of old forest in recover relatively quickly after stand-destroying the CWHds is a serious issue in the valleys, especially disturbances, provided biological legacies such as at the lower elevations typically occupied by this snags and large downed logs persist on site. subzone. Most of the remaining patches of old However, the transitional (i.e., between coast and growth outside of parks are fragments in a matrix of interior) nature of the climate is reflected in periodic younger second growth. climatic extremes (summer drought, cold air ponding, outflow winter winds, heavy snows). The Legal Protection and Habitat climatic factors can delay forest regeneration and Conservation could slow recovery after disturbance. There is no legal protection for plant communities Conservation and except for those within protected areas and parks. Known sites occur within several provincial parks Management including Tweedsmuir (especially along middle Dean River and on east side of Talchako River), Status Homathko, Mehatl, Chilliwack Lake, Skagit Valley, The western hemlock–Douglas-fir/electrified cat’s- Garibaldi, and Birkenhead Lake. tail moss plant community is on the provincial Red Riparian management area guidelines are unlikely to List in British Columbia. It is ranked S2 in British be relevant for most occurrences of this plant Columbia. Its global status is unknown. community. Old growth management areas could address, at least in part, some occurrences provided Trends old forest objectives cannot be met in the non- Exact calculations of the areal extent of this once timber harvesting land base. predominant forest system are difficult to project. By definition, the zonal forest type of each biogeo- climatic subzone is the expression of the dominant landscape and climatic conditions and frequently

3 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 3 Identified Wildlife Provisions • relatively lightly damaged and can be expected to recover to a more natural state; Sustainable resource management and • part of a network of reserve areas (e.g., adjacent planning recommendations or linked to other WHAs or to OGMAs or to This matrix forest community used to be wide- riparian reserves); spread, forming the predominant forest matrix • in areas where the forest community has been throughout much of its range. It is recommended to: severely depleted; and ™ maximize connectivity of old forest within the • adjacent to natural occurrences of other plant CWHds1; communities. ™ maintain or recover at least 20 large occurrences Size in good condition across the range of the plant community; The size of the WHA should be based on the extent ™ maintain or restore occurrences to as close to of the plant community occurrence. Typically natural condition as possible and practical; and occurrences of this plant community are a ™ wherever possible, protect remaining occurrences minimum of 40 ha. through the placement of old growth management areas. Design The WHA should include the entire occurrence of Wildlife habitat area the community plus ±100 m (approximately two Goals heights) surrounding the community. Maintain or recover known occurrences that could Boundaries should be designed to minimize edge not be addressed through landscape level planning effects and be windfirm. and the designation of old growth management General wildlife measures areas. Goals Feature 1. Maintain or restore plant community to a natural Establish WHAs at occurrences that have been state (i.e., same species composition, physical structure, and ecological processes as natural confirmed by a registered professional in consulta- examples of the plant community; see Green and tion with the B.C. Conservation Data Centre or Klinka 1994). Ministry of Forests regional ecologists. Priority for 2. Maintain or enhance old forest structure WHAs should be any old (structural stage 7) occur- (i.e., large old trees, range of tree sizes, large rences of this community and include within a snags, down logs, canopy depth and roughness, matrix of younger stands if necessary to attain a multiple vegetation strata, horizontal patchiness 40 ha minimum size that and mature (structural of understorey) (Spies 1998). stage 6) occurrences >100 ha that are in a relatively 3. Maintain forest-interior conditions. natural state. As a lower priority, establish WHAs up 4. Prevent physical disturbance, especially of the to 100 ha within regenerating younger forests soil. containing the same plant community, to recover 5. Minimize introduction and spread of non-native community to climax condition. Select areas that are species. (in order of priority): • the oldest, most structurally complex secondary forests available, ideally stands containing some old residual ;

4 Accounts and Measures for Managing Identified Wildlife – Accounts V. 2004 Measures Cross References Access Spotted Owl • Do not develop roads or trails. References Cited Harvesting and silviculture • Do not harvest or salvage except when required B.C. Ministry of Forests and B.C. Ministry of to create a windfirm edge. Environment, Lands and Parks (MOF and MELP). 1995. Biodiversity guidebook. Victoria, B.C. Forest • Do not remove non-timber forest products. Practices Code of B.C. guidebook. Pesticides Green, R.N. and K. Klinka. 1994. A field guide to site identification and interpretation for the • Do not use pesticides. Forest Region. B.C. Min. For., Victoria, B.C. Land Recreation Manage. Handb. No. 28. Pojar, J., C. Rowan, A. MacKinnon, D. Coates, and P. • Do not develop recreational sites, trails, or LePage. 1999. Silvicultural options in the Central facilities. Coast. Land Use Coordination Office, Victoria, B.C. Unpubl. report. Additional Management Spies, T.A. 1998. Forest structure: a key to the Considerations ecosystem. Northwest Sci. 72:34–39. Minimize impacts to vegetation, soils and hydrology when operating adjacent to a WHA, particularly during road development and maintenance.

Information Needs 1. Further inventory and confirmation of classi- fication to clarify the extent of this community. 2. Mapping of present-day occurrences and assessment of structural stage and successional dynamics of the occurrences. 3. Identification of the most optimal networks to link this and other listed communities in the CWHds1.

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