Photo: © Sharmin Gamiet

Vegetation on sites

The CWHvm subzone in Seymour Watershed is dominated by western hemlock (Tsuga heterophylla), and silver fir (Abies amabilis) which are present on all sites studied. It is divided into 2 variants, a lower elevation, submontane (vm1) variant, and a higher elevation, montane (vm2) variant. In this watershed, sites in the vm1 variant are generally located at less than 650 metres, indicated by the presence of western redcedar (Thuja plicata), while sites in the vm2 variant are generally located at higher than 650 metres, indicated by yellow cedar (Chamaecyparis nootkatensis). At around 850 metres the mountain hemlock (MH) biogeoclimatic zone grades into the CWH zone. In this watershed, some sites at around 800 metres have the occasional mountain hemlock (Tsuga mertensiana) trees. Sites in the vm2 variant are moister, cooler and have thicker forest floors than sites in the vm1 variant.

Western hemlock, silver fir and mountain hemlock trees form ectomycorrhizae, while western red cedar and yellow cedar form arbuscular mycorrhizae. Ectomycorrhizal fungi usually form macroscopic fruiting bodies while arbuscular mycorrhizal fungi form microscopic reproductive structures.

All canopy trees on the sampling sites were greater than 250 years old. In the upper watershed some trees were significantly older than 500 years.

Further Readings:

Burns, R.M. and B.H. Honkala. 1990. Silvics of North America. Vol 1. Agriculture Handbook 654. Forest Service. Conifers. USDA. Washington, D.C. pp. 675.

Green, R.N, and K. Klinka. 1994. A Field Guide to Site Identification and Interpretation for the Vancouver Forest Region. Min. of For. Research Branch. Victoria, B.C. pp 285.

Meidinger, D., and J. Pojar. 1991. Ecosystems of British Columbia. Min. of For. Research Branch. Victoria, B.C. pp 330.