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.
Yellow birch is the longest lived of our native birches and is quite tolerant of shade. These characteristics made it a strong component of our Acadian forest, especially on the upland hardwood sites. While it grows well in moist conditions, such as alongside streams, it does poorly where there is standing water. It is often found growing in association with eastern hemlock, red and sugar maple and white pine. 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, while bog birch lives up to its name, being found in acidic, boggy areas. It needs full sun to thrive and is usually surrounded by plants with similar tolerances – willow, rose, Labrador tea, larch and black spruce.
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.
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.
Yellow birch is still relatively common in the upland hardwood areas of the province, but these types of forest are becoming rare in all but the younger age classes. Large, high quality yellow birch are not common. Since it is such an important component of the Acadian forest, we need to continue efforts to protect and encourage this species. Yellow birch is one of the key species we use at Macphail Woods to restore degraded woodlands. We have planted them (with a variety of other appropriate species) in small patch cuts made in old field white spruce and in both hardwood and softwood thinnings. We have also used them to add value and diversity to conifer plantations once those trees are providing some shade.
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”. An interesting note is that early settlers and many people up to the twentieth century, believed that the yellow birch was actually two separate species. Younger yellow birch were easily identified, but the the old and large yellow birch have a distinctive black bark and loses much of it’s younger looks. This lead many people to believe that “Black birch” was actually a separate species of birch. The recorders of the time indicate that the birches were among the island’s more important trees. Many records have “black birch” listed and it occurs more often than yellow birch, which indicates the forests were in a mature old-growth forest state. Generally, it was described as common throughout the island. Yellow birch was described in many sites, including along Richmond Bay, Trout River, New London, Point Prim, Pinette River, Wood Islands, Mount Stewart, and a number of other areas.