Biogeoclimatic zones of British Columbia
The system of biogeoclimatic ecosystem classification was partly created for the purpose of managing forestry resources, but is also in use by the British Columbia Ministry of Environment and Climate Change Strategy and other provincial agencies.
A biogeoclimatic zone is defined as "a geographic area having similar patterns of energy flow, vegetation and soils as a result of a broadly homogenous macroclimate.
Subzones, which are divisions of zones based on more regional climates, have their connotative codes in lower case with the first letter denoting relative moistness and the second relative temperature; thus the northeastern BWBS with its warm thundery summers has been mapped as BWBSmw for "moist warm" while the Alsek Ranges subzone in the northwestern panhandle, stormy in all seasons with winds blowing from glaciers, is BWBSvk for "very wet cool."
Many spruce stands are quite open, with a well-developed shrub layer dominated by a variety of willows (Salix glauca, S. planifolia, S. scouleriana, S. bebbiana) and scrub birch (Betula glandulosa).
Other common shrubs include Potentilla fruticosa, Shepherdia canadensis, Empetrum nigrum, Vaccinium vitis-idaea, V. caespitosum and Ledum groenlandicum.
In addition to the feather mosses Pleurozium schreberi and Hylocomium splendens, the forest floor contains a diversity of lichens (Coates et al.
The thick carpet of moss is of Hylocomium splendens, Pleurozium schreberi and Ptilium crista-castrensis, and the lichen Peltigera aphthosa (Coates et al.
Wetter spruce sites have Lonicera involucrata, Cornus sericea, Gymnocarpium dryopteris, Tiarella trifoliata, Equisetum arvense and Mnium mosses.
Characteristic species of spruce bog, fen, or swamp ecosystems are Salix spp., Betula glandulosa, Ledum groenlandicum, Carex spp.
Unlike the interior high-elevation transition zones (SWB, ESSF), spruce is usually scarce or absent and mountain hemlock is abundant.
Herbs characteristic of the ESSF forest include Valeriana sitchensis, Gymnocarpium dryopteris, Rubus pedatus, Streptopus roseus, Veratrum viride, Athyrium filix-femina, Cornus canadensis, Lycopodium annotinum, Tiarella spp.
At the upper parkland elevations of the ESSF, closed forest and tree islands of spruce and subalpine fir are interspersed with moist herb meadows and drier ericaceous heath.
The meadows typically include the herbs: Valeriana sitchensis, Veratrum viride, Senecio triangularis, Lupinus arcticus, Thalictrum occidentale, Epilobium angustifolium, Pedicularis bracteosum, Castelleja miniata, Erigeron peregrinus, Carex spp.
Subalpine heath includes Empetrum nigrum, Cassiope mertensiana, C. tetragona, Phyllodoce empetriformis, P. glandulifera, and Vaccinium caespitosum (Coates et al.
A second rain peak occurs in June, but the quantity rarely matches evaporation; therefore, winter is the primary moisture recharge season.
Summers are warm in northern parts of the BG, and hot in low-elevation southern areas such as the Thompson River valley between Kamloops and Lytton.
The BG represents "fingers into Canada" of the intermontane steppe which is extensive in the Great Basin of the western United States, and as such it is frequented by animal species at their northern limits.
Trembling aspen, paper birch, and black cottonwood are common seral species, and bigleaf maple is present in some parts of the southwestern coastal transition area (wet warm subzone or IDFww).
Common shrub associates include: Ribes lacustre, Lonicera involucrata, Cornus sericea, Rosa acicularis, Symphoricarpos albus and Acer glabrum.
The well-developed herb layer contains Linnaea borealis, Cornus canadensis, Aralia nudicaulis, Actaea rubra, and Osmorhiza chilensis, together with Equisetum and Carex spp.
Bog forests with Sphagnum spp., Ledum groenlandicum, and Gaultheria hispidula are infrequent but usually have a tree canopy of pure spruce (Coates et al.
The climate is "Csb" Cool Mediterranean, and the droughty summers inhibit development of a climax Western Red Cedar-Grand Fir association.
A typical spruce or redcedar–spruce stand on a seepage ecosystem has a diverse shrub layer dominated by Oplopanax horridus, Ribes lacustre, Cornus sericea, Acer glabrum, Rubus parviflorus, Viburnum edule, and Lonicera involucrata.
Seral communities on mesic sites in the north of the ICH have a mixed overstorey of spruce, subalpine fir, lodgepole pine, paper birch, and trembling aspen.
Typical shrubs are: Rubus parviflorus, Viburnum edule, Rosa acicularis, Paxistima myrsinites, Amelanchier alnifolia, Shepherdia canadensis, Alnus viridis, and Vaccinium membranaceum.
Major herbs include: Cornus canadensis, Clintonia uniflora, Aralia nudicaulis, Lathyrus nevadensis, Rubus pubescens, Smilacina spp., Orthilia secunda, Osmorhiza chilensis, and Petasites palmatus.
The moss carpet is dominated by Rhytidiadelphus triquetrus, Ptilium crista-castrensis, Pleurozium schreberi, and Hylocomium splendens (Coates et al.
[13][14] Hemlock is easily seen along the Stewart-Cassiar Highway at Thomas Creek, but drops out within a kilometre northward as the hitherto-scarce lodgepole pine becomes abundant; this marks an abrupt change to the BWBS zone.
A very productive rain-fed forest occurs along the British Columbia coast from Haida Gwaii and Stewart south to Metchosin on Vancouver Island.
[17] Douglas-fir is often present and sometimes dominant in warmer, drier sections as far north as Kemano, while Sitka spruce is important in wet areas near tidewater.
