The four birches native to Prince Edward Island range from the common to the very rare. As with other families, each member has a distinct place in our Island ecosystem, though there may be two or even three species growing in the same area. Each has its own tolerance for sun and moisture. Growth rates, life span and wood quality also differ widely.
All birches have toothed leaves that are simple and alternate. When young, it is difficult to distinguish species by bark, since they all have reddish-brown, shiny bark with white spots (lenticels). Yellow birch can grow to be one of our largest deciduous trees, reaching a height of 21 m (70 ft) and up to .9 m (3 ft) in diameter. The bark of older yellow birches is a golden yellow and tends to shred rather than peel in large blocks. If the bark of yellow birch twigs is scraped, it produces a strong scent of wintergreen. Once it is six or seven years old, white or paper birch is most easily recognized by its brilliant white, peeling bark. Grey birch also has white bark, though it peels very little and has distinct black marks under each branch. It is also called wire birch, due to the large number of fine branches. As you might expect, bog birch is a small tree, rather more like a shrub. It rarely grows more than 3 m (10 ft.) high and on all specimens I have encountered the bark remains like that of any juvenile birch.
White birch is an early successional tree, growing on dry, exposed sites, including burned areas. It grows poorly in shade, and is often associated with poplar, pin cherry and balsam fir. Grey birch can often be found with white birch and its associated species, again on dry sites.
Birch seed is grouped in cone-like strobiles and can be collected by hand from shorter trees. Pick when the strobiles are fully developed and break apart quite readily. On taller trees, it is often possible to find strobiles under trees after a strong windstorm. Birch seed is easy to clean. Simply rub the strobiles over a screen or strainer that will allow the seed to drop through and catch the bracts. Seeds need a cold period before planting, so they can be stored in a fridge with a small amount of damp peat or potting soil. In the spring, sprinkle the mixture on top of a seedbed, but do not cover with soil. Birch seed needs light for germination but doesn’t like to dry out. A slatted table (providing 50% shade) and regular light mistings provide optimal conditions for germination. My one attempt with bog birch was unsuccessful, probably due to an insufficient cold period, but I will be trying again to reproduce this rare plant.
Birch seed is an important food source for many winter birds, including American goldfinch, pine siskin, northern junco, blue jay, and the chickadees and sparrows. Birches regularly produce heavy crops of seed and larger trees can be quite important to local populations of birds. During the Christmas bird counts, especially if the surface of the snow is crusty, you can see dozens of small birds chasing after birch seed that has been scattered by the wind. While the seed is important for wildlife (including small mammals), the trees are used in many other ways. Ruffed grouse can often be found in birch trees during the winter eating the buds, and snowshoe hares browse the twigs. In spring, birch flowers attract many insects, which in turn attract large numbers of migrating warblers.
Birches can also be important nesting sites for red-tailed hawks and vireos, as well as cavity nesting birds such as chickadees and woodpeckers. Small strands of birch bark are the key materials used by vireos in their hanging nests, while many other birds and red squirrels incorporate this material into the nest and den linings. In addition, yellow-bellied sapsuckers regularly drill into birches to allow sap to run out and attract ants. As you can see just from this partial list of wildlife uses, the birches are important to a wide variety of species.
White and grey birch are two of our most common hardwoods and need very little help in the form of conservation. While important trees, they do very well in clearcuts and disturbed sites, as long as the soil is dry, so we are fortunate to still have large populations. This doesn’t mean that we should discriminate against them they are still excellent trees to plant in windbreaks and around homes, as well as when restoring severely degraded sites.
Although we cannot go back in time to see the forests of PEI at the time of settlement by Europeans, we can acquire a reasonable picture by analysis of the written records of that time. This has been achieved by Dr. Doug Sobey in his work “Early Descriptions of the Forests of Prince Edward Island”. White birch was recorded as being located in a few local areas, but was prominent in the area of the great fires that ravaged the north-east of the island during the French period. White birch was recorded to be of a much smaller size than yellow birch, however there are records of large individual white birch trees being selected by Mi’kmaq for canoes capable of carrying many people.