Gray birches are native to Northeastern North America and like their close relatives the Paper birches are a pioneer species, springing up in abandoned fields, woodland edges or disturbed areas. After land has been logged they are one of the trees along with poplar and willow that often germinate first, providing much needed shade for second succession trees and plants.
Gray and paper birches are easily confused as both have white bark, and they often grow together in the same habitat. However, they can be easily distinguished by bark texture or leaf shape. Gray birch bark doesn’t peel and has sharply serrated leaves. White birch has leaves that look and sound more like those of the poplar. Both birches are almost identical genetically.
Neither White or Gray birches are long – lived trees, but those that find enough moisture will grow into sturdy adults that may live for more than a hundred years. I have a few like this on my property.
Prior to the arrival of European settlers, Gray birch was held in high esteem by many Native American tribes. The Iroquois and Mi’kmaq tribes valued this tree for its medicinal properties for treating infected cuts and wounds (reinforcing the reality that native peoples have access to information that science is just getting around to learning today). Northeastern Tribes made wide use of the outer bark of white birch for constructing canoes and making wigwams. Birch bark was also used to make hunting and fishing gear; musical instruments, decorative fans, and even children’s sleds and other toys. Today, the wood is used primarily for pulp, furniture, and firewood.
Renowned Forest Scientist Suzanne Simard discovered that when Paper birch was allowed to grow along with Red cedar and Douglas fir in the Northwest the birch protected the other trees from Armillaria, an aggressive root pathogen that eventually kills any tree in its path. Armillaria is found everywhere but in the Antarctic. Paper birches also contain bacteria with antibiotic properties that help protect conifers from other diseases. I suspect that Gray Birches protect our eastern forests in similar ways that Paper birches do in the west because the two are close relatives sharing almost identical DNA structures. Birches have another advantage. When the trees come down in storms the logs break down very rapidly enriching the soil. Birches support the mycelial networks that connect all trees underground creating pathways for nitrogen and carbon to be exchanged. Simard argues that tree plantations would benefit greatly from allowing birch to grow alongside fir because they protect them (and other species) from disease. A forest lacking in diversity is weakened in many ways that we don’t yet understand.
Birches have other attributes worth mentioning. Birch seeds are an important food source for many winter birds, including goldfinches, pine siskins, northern juncos, blue jays, chickadees and sparrows. Go out any morning after a wind blown snowstorm and you can see that the surface of the snow is covered with tiny birch seeds. Juncos, blue jays, titmice, chickadees, cedar waxwings, ruffed grouse and other birds also eat the early spring buds. While the seeds are important for wildlife including small mammals, the trees are used in many other ways too. Snowshoe hares and cottontails browse the twigs. In spring, birch catkins attract many insects, which in turn attract large numbers of migrating warblers and provide nourishment for bears.
Gray birches are also hosts for the caterpillars belonging to several species of butterfly, including tiger swallowtails, white admirals, mourning cloaks, and tortoiseshells.
Birches can also be important nesting sites for red-tailed hawks and vireos, as well as for cavity nesting birds like 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 nest and den linings. In addition, yellow-bellied sapsuckers regularly drill into birches to allow sap to run out. Boring holes into birches attract ants for others to feast upon. As you can see birches are important to a wide variety of species.
Anyone that is familiar with birches knows that both Gray and to a lesser extent White birch are vulnerable to high winds and ice. During last winter’s ice storm in December I lost many of my birches. I was devastated because in all these years I have never lost as many trees at once as I did in that storm. For the rest of the winter I looked at bent and broken birches feeling heartbreak. When spring came I was overwhelmed with the amount of debris that I thought I had to clean up. It took a while to accept that in an intact forest like mine, birch trees will fall more easily than other species have in heavy winds, ice, and snow. It is the nature of birches to bend and break. It’s not as if I wasn’t aware that my woods were peppered with fallen birches; the difference was that they hadn’t all come down at once. Birches open areas to more sunlight without disrupting the integrity of the forest itself.
As the season progressed I witnessed how the dying birch created more habitat for birds and young saplings. One big cluster of fallen birches created a protected nesting site for the grouse to raise her family on the other side of the fence. As more light reached the forest floor new wildflowers appeared. My Lady slippers sprung up after I cleared some debris below the house, and later fragrant pyrola carpeted the ground in the same area. And thanks to Forest Scientist Suzanne Simard, I learned how important the dying birches were in terms of protecting the other trees in the forest from disease. I continue to note how fast the logs decay and how rich the earth smells whenever I pick up parts of a rotting log, something I do quite frequently now. Wood frogs and toads hide here! If I dig below the surface just an inch or two I can see the colorful complex mycelial network that disappears into the leaf litter. Although I am hoping that this winter will be kinder to trees than last winter was, I am also aware that with climate change upon us that more extremes are ahead. I hope that the birches will continue to teach me a lesson about acceptance of what is, and what will be. When I look at the birch logs stacked for this winter’s firewood or I walk by logs crisscrossing the ground in the woods all I can think of is that these trees are caring for the forest as a whole by dying, and I give thanks for actively participating in the endless circle of life.