Birch Trees - Kate Crowley
Going Nature’s Way
By Kate Crowley
photos by Mike Link
In the winter, as I ski through our forest I am able to see the trees so much better. It is a mixed forest, meaning we have conifers (pines and firs) and hardwoods (maples, oaks, aspen and birch). I have noticed that certain species tend to be found concentrated in different parts of the forest, which makes sense, since they differ in their specific needs for moisture, sun and shade.
Of all the trees, my two favorites are the Eastern White Pine (Pinus strobus) and the Paper Birch (Betula papyrifera); also known as White Birch. We have a good number of old growth white pines; trees that are over 100 years old. They stand as memorials to the vast forests of a century ago that covered this part of the state. And they are the progenitors of the new growth spreading through the forest, something we are very pleased to see.
Efforts to replant white pines in the 20th Century were mostly unsuccessful, because the stock was not from the original inhabitants which had evolved to the particular conditions of this land. Additionally, the burgeoning white tail deer population found the tops of the young trees delicious. Old growth trees such as ours have continued to produce cones and subsequently, their offspring that have taken root and prospered. If we are lucky and climate change doesn’t bring this renewal to a halt, someday our grandchildren and possibly their grandchildren will be able to wander among old giants once again.
Paper Birch is a tree of the ‘north country’. In fact, Minnesota is at the southern edge of its range and we can expect that line to continue to move northward as average global temperatures rise. This is a tree that requires cool, moist conditions to prosper. Surprisingly, paper birch was not always so common in our state. Like the white-tail deer who now consume the young trees, it arrived after the logging of the pines and fires of the late 19th and early 20th centuries.
If you have driven along the North Shore on Highway 61 in recent years, you have seen the sad sight of dead and dying birch all the way to Grand Marais. Paper Birch is especially sensitive to drought conditions and in the mid-2000s they were hit hard. When this happens they become susceptible to the bronze birch borer, which seals their fate. Because so many of us associate the beautiful white birch with that part of our state, the Superior National Forest has proposed planting these iconic trees along a 65 mile stretch between Grand Portage and Schroeder. This is a very expensive undertaking, not only in the labor involved, but in the additional fencing that would be needed to protect the young trees from the voracious deer. I do hope we will one day again see healthy birch trees lining the Lake Superior shore.
Here on our property, I look at the birch trees carefully for any signs of disease. Thankfully, we have not suffered any extended period of drought and while they don’t do well in shade, ours have enough surrounding forest to give some overall protection (in the form of fallen leaves and needles) to act as a mulch over the sandy soil.
We think of Paper Birch as having very white bark. This is the case, especially in summer, when they contrast with all the greenery around them, but in the winter, when their branches and trunks have freshly fallen snow clinging to the bark, they appear a dingy grey green. Still I find beauty in their peeling tendrils of bark and their lacy branches up top. It is also at this time of year that I find the snow sprinkled with their tiny, delicate seeds.
At the tips of their branches are last year’s catkins (flowers), now clusters of tightly packed seeds that rain down when the wind is strong. They are yellowish brown in color and resemble the fleur-de-lis in shape. These seeds are valuable winter food for many of our resident birds.
Humans have found the paper birch to be a useful tree for centuries. The local indigenous people, today’s Ojibwe, have used the bark of the tree for shelter, transportation (canoes) and cooking utensils. Its bark has the unique ability to hold water when made into a container and to not burn when that container is placed above a fire. However, birch bark on its own is one of the very best fire starting materials you can find; it will burn even when wet. Artisans use the tree to create beautiful pieces of furniture with its smooth, pale grain. And in popular culture you will find images of birch trees gracing wallpaper, fabric, and framed pieces of art. There is something innately pleasing about the pattern of black and white found on the bark.
The poet Robert Frost was enamored with birch trees and one of his well-known poems is titled “Birches” although it is focused on the sport of ‘swinging’ from the trees; something few of us have ever done, but it gives me another perspective to consider as I ski through our forest and evaluate our birch trees.