- Education and Science»
- Geography, Nature & Weather
Why Trees are Important
Trees of British Columbia
Trees are long-lived, woody plants that are normally taller than 6 metres. There are 2 types of trees in B.C.: coniferous and broadleaf. Conifers, or cone-bearers, have needles or small, scale-like leaves. Most conifers are evergreens, but some, such as larches, shed their leaves in winter. Most broadleaf trees lose their leaves in autumn and are often called deciduous trees (meaning "falling off" in Latin). B.C. has one broadleaf tree that doesn't lose its leaves in autumn: arbutus.
A Tree can be a Home
A single tree can provide a home or a food source for many different animals. Roots bind soil and play host to a multitude of beneficial fungi, and even support certain semi-parasitic plants such as Indian paintbrush. Trunks provide a substrate for numerous species of moss and lichen, which in turn are used by many animals for shelter and nesting material. Tree cavities are used by everything from owls to squirrels to snakes.
Leafy canopies support an amazing diversity of life. Myriad birds depend on mature trees, as do scores of insects. Both the seed cones of coniferous trees and the fruit of deciduous trees are consumed by all manner of wildlife.
A group of trees can provide windbreak, camouflage or shelter, and can hold down soil, thus preventing erosion. Streamside (riparian) woodlands are vital to protecting water quality. Their dense root layers filter out sediments and other contaminants that would otherwise enter watercourses. It is no mystery why Canada's healthiest rivers are also those that have abundant, undisturbed woodlands alongside them.
Tsuga heterophylla forest
Responsibly managed forests
There are many types of forest communities, and the types of soils on which they occur largely dictate their species composition. To some extent, the types of trees within a forest control what other species of plants and animals are present. Old-growth forest is critical habitat for many species that use the fallen or hollowed-out trees as nesting or denning sites.
Many species of invertebrates live within or under the bark, providing food for birds. Fallen, decomposing logs provide habitat for snakes, salamanders, mosses, fungi and invertebrates. The logs eventually completely degrade into soil to perpetuate the continued growth of plant life and retain organic matter in the ecosystem. Large forests retain carbon dioxide, helping to reduce global warming. One giant old-growth tree can extract 7 kg of airborne pollutants annually and put back 14 kg of oxygen. Responsibly managed forests can also sustain an industry that provides wood products and jobs.
Pacific Dogwood, my favorite tree
This beautiful, small understorey tree has delicate flowers, shiny red berries and red autumn leaves. The showy, whitish dogwood "flowers" are actually floral bracts that surround the true cluster of tiny, greenish flowers. Golf-club heads, daggers and engraver's blocks have been made from the tough wood. The berries attract birds and provide food for small mammals.
Pacific dogwood is B.C.'s provincial flower. Unfortunately, many Pacific dogwoods have been lost to dogwood anthracnose a fungal disease.