The Biogeoclimatic Ecosystem Classification


Biogeoclimatic Zones

Here is a link to the BEC map of the district.

Since 1975, the BC Ministry of Forests has been systematically developing an ecosystem classification of the forest and range lands of the province. This classification is based, with some modifications, on the biogeoclimatic system developed in the 1960’s and 1970’s by Dr. V.J. Krajina and his students a t the University of British Columbia. The system incorporates primarily climate, soil, and vegetation data. The resulting biogeoclimatic ecosystem classification (BEC) provides a framework for resource management, as well as for scientific research.

Biogeoclimatic Ecosystem Classification (BEC) is a system that groups similar segments of the landscape (ecosystems) into categories of a hierarchical classification system. An ecosystem is the product of a complex environment. For the purposes of BEC, an ecosystem is defined as a particular plant community and its associated topography, soil, and climate. While boundaries between ecosystems in the landscape can be abrupt, they more often tend to be gradual.

Climate is the most important factor influencing the development of forest ecosystems. The Douglas-fir forests of interior regions reflect a much warmer, drier climate than the moist red cedar-hemlock forests on the west coast, or the snowy mountain hemlock forests at high elevations. Within each of these climatic areas, ecosystems vary because of differences in topography and soil. Rocky ridges are relatively drier than lower slopes and valley bottoms.

Vegetation is important when developing the ecological classification because it is readily visible, and it reflects the environment, biology, and history of a site.

Coastal Western Hemlock Zone

Douglas-fir - Pseudotsuga menziesii

The Douglas-fir can be found up to 860m (2800') on the coast. Young trees form a broad, sloping pyramid with straight or drooping lower branches while old trees develop heavy, crooked limbs with an irregular top. The bark is deeply fissured in reddish-brown ridges. Quickly identify the Douglas-fir by its protruding, triple-pronged bracts on the cones. It can exceed 60m (200') in height and 1.8m (6') in diameter.

Western Hemlock - Tsuga heterophylla

The Western hemlock is most easily identified by its drooping tip. It grows 30m to 45m (100' - 150'). The needles are flat, flexible, rounded at the tip and spread into two rows along the branch. Its bark is reddish to grey-brown, thick and deeply furrowed into broad, scaly ridges. Natives of southeast Alaska used to make coarse bread from the inner bark.

Western Red Cedar - Thuja plicata

A giant on the west coast, it often grows over 45m (150') high and 1.8m (6') in diameter. Branchlets hang like fronds from the main boughs and have scaly, blunt leaves pressed in pairs tightly to the twig. The bark is thin and stringy, and can be pulled off in long strips. The reddish wood is fragrant and splits easily.

Mountain Hemlock Zone

Whitebark Pine - Pinus albicaulis

This crooked tree is the true indicator of tree line in the Coast Mountains. It is recognized by the bundles of five needles crowded at the ends of its flexible branches. These branches allow the tree to withstand heavy snow and ice loads. The bark of this primitive pine is smooth and whitish gray, becoming scaly with age. It can be found on dry, rocky slopes in the subalpine to timberline.

Subalpine Fir - Abies lasiocarpa

At the lower elevations of its range, this common fir can reach heights of 15m to 30m (50' - 100'), but it becomes shrubby as it approaches treeline. Its long, spire-like profile allows it to easily shed the heavy Coast Mountain snowfalls. The needles are crowded, bluish green, with white rows of stomata on both sides.

Mountain Hemlock - Tsuga mertensiana

Found at elevations beyond 790m (2600') and up to timberline. The dark green needles grow around the twigs and give a tufted appearance. Like the Western hemlock, the tip of the tree droops. The dark brown bark has flat scaly ridges and deep furrows. The needles are about 1" to 2" long, flat and blunt, and have two fine white lines underneath.

Yellow Cedar - Chamaecyparis nootkatensis

A shaggy tree usually less than 25m (80') high. It tapers to the top and the limbs sweep out and down with fern-like fronds hanging from them. The bark on older trees is a distinctive dirty white from a distance. The scaly overlapping leaves are prickly when stroked against the grain, unlike the red cedar. The soft wood is light yellow in colour with a pungent fragrance.

Coastal Mountain-Heather Alpine Zone

Western Anemone - Anemone occidentalis

This is one of the first plants to show after the snow melts, but quickly turns to seed. The thick stems are hairy and the flower is waxy white with yellow stamens in the centre. As it turns to seed, a white woolly head develops which earns this flower the nicknames, "tow-headed baby" or "mouse on a stick".

Sitka Valerian - Valeriana sitchensis

This flower blooms throughout the summer. It is 0.4m to 0.6m (16" - 24") high with a dense head of small white or pinkish flowers, and opposing stems of 3 to 7 leaflets. Natives ate the thick root stock to treat stomach ailments.

Meadow Spirea - Luetkea pectinata

This plant's nickname "partridge foot", refers to the fringed leaves shaped like birds' feet that grow close to the ground. It is found in damp, open places in the subalpine and alpine. This small, erect plant (2" to 4") grows in groups and has small, white flowers.

White Moss Heather - Cassiope mertensiana

A common ground cover plant that grows in clumps. The small white flowers are bell-shaped. The twigs are covered with small, overlapping scales.

Red Heather - Phyllodoce empetriformis

A common low-matted plant that is topped with red, bell-shaped flowers. Unlike White Heather, the leaves on the twigs are separate and needle-like.

Indian Paintbrush - Castilleja miniata

This flower may be up to 0.6m (2') high with narrow, sharp-pointed leaves. The red leaf-like bracts cover up the tiny greenish flowers and give the overall bright red colouring.

Indian Hellebore - Veratrum viride

This tall plant (1m to 1.5m/39" to 59") has large, heavily ribbed leaves. Look closely for the small flowers which are an unusual yellowish-green colour and form thin branching spikes. This plant is extremely poisonous.

Cinquefoil - Potentilla

Easily confused with buttercups, distinguish by checking for notched flower petals which are not shiny, and green sepals showing between each petal. The name derives from French, meaning five leaves.

Lupine - Lupinus arcticus

These purple flowers cluster in long spikes. The bright green leaves are long and arranged like spokes on a wheel. Drops of moisture collect at the base of the leaves to provide extra moisture to the plant.

White Rhododendron - Rhododendron albiflorum

This erect, slender branched shrub grows 1m to 2.5m (3' to 7') tall. The oblong leaves have rusty hairs on the upper surface, and cluster along the branch, especially at the tip. The leaves turn bronze in the fall. The flowers are white to creamy, large and cup-shaped. They grow in clusters of two to four.

Black Huckleberry - Vaccinium membranaceum

Absolutely delicious! The shrubs are densely branched and grow up to 1.5m (4') tall with finely toothed, lance-shaped leaves. The flowers are creamy-pink to yellow-pink and produce purplish or reddish-black berries.

Kinnikinnick - Arctostaphylos uva-ursi

An evergreen shrub with long, flexible rooting branches that often forms mats. The oval- to spoon-shaped leathery leaves alternate on the branch. It produces small, pinkish-white flowers which turn into bright red berries. Edible but bland with large seeds.

Interior Douglas-fir Transitional Zone

Interior Douglas-fir - Pseudotsuga menziesii var. glauca

The interior variety of Douglas-fir is distinguished by its bluish-green needles and its shorter cones, which are less than 8 cm long. In the dry parts of the region, Douglas-fir’s thick bark and tall, clear bole help protect it from fires. It is widespread and common on a wide variety of sites at low to mid elevations; restricted to dry, warm aspects at sub alpine elevations.

Lodgepole Pine - Pinus contorta var. latifolia

Lodgepole pine is distinguished from all other pines in the region by its needles, which are borne in bundles of two. It is abundant where forest fires have been common. Although mature lodgepole pine has thin bark and is easily killed by fire, many of its seeds are sealed shut by a resin that must be melted before the seeds are released. Consequently, initial densities of lodgepole pine as high as 100,000 trees per hectare are not unusual. Lodgepole pine is widespread and common from low elevations to treeline on a wide variety of soils and drainage conditions.

Sources:

Trees, Shrubs & Flowers to Know in B.C. C.P. Lyons, 1991.

Plants of Coastal British Columbia Pojar & MacKinnon (ed.), 1994.

Plants of Southern Interior British Columbia Parish, Coupe & Lloyd (ed.), 1996.

Ecosystems of British Columbia Meidinger & Pojar (ed.), 1991.