Black Cottonwood: The tree that snows!
Photos by DON BARTLING Black Cottonwood grow on the banks of Boundary County lakes, rivers and creeks and are identified by their thick, deeply furrowed gray bark.
The leaves of a Black Cottonwood tree grow alternately in a pale green shade, with leaf size of 2-2.5 inches in length and width. The leaves are oval to heart shaped. Leaves of mature trees can display a light rust on the side facing the ground.
“Trees, for example, carry the memory of rainfalls. In their rings we read ancient weather — storms, sunlight, and temperatures, the growing seasons of centuries. A forest shares a history, which each tree remembers even after it has been falled.” — Anne Michaels
Populus balsamifera is a large cottonwood tree of the northwestern United States. The tree, a member of the willow family, can reach to 100 feet tall, and achieve a 6-foot trunk diameter. The bark is rough and dark-colored, thus the name “black cottonwood.” The leaf blades are oval to heart-shaped, with a point on the end.
The black cottonwood being in moist areas allows for rapid growth, so rapid that they are one of the fastest growing tree and largest broadleaf tree in Boundary County. The rapid growth doesn’t produce durable wood, so the wood is weak. Large upper limbs are extremely susceptible to breaking off during windstorms or under a considerable amount of snow or ice.
However, broken branches and remaining stumps help perpetuate the species. New trees can sprout from cut stumps, limbs partially buried in soil or from surface roots. As a shared-tolerant pioneer species, black cottonwood rely on their rapid growth to maintain the dominant position on barren soil, such as gravel bars disturbed by flood waters.
As seen on the Kootenai River, wildlife utilize cottonwoods in many ways. The large upper limbs of cottonwoods provide sites for the huge, platform stick nests of bald eagles and osprey. Colonies of blue herons also build large stick nests in the crowns of cottonwoods.
Rotten trunks or places where limbs have broken off present cavities for woodpeckers, great horned owls, wood ducks, squirrels, raccoons and numerous songbirds. Beavers easily gnaw through the weak wood to topple trees for food and for building lodges and dams.
Deer, moose and elk eat the twigs and buds and they can hinder the growth of cottonwoods even more by rubbing their antlers on young saplings. If a cottonwood can survive the elk, deer, mice and beavers for 10 years, it will be old enough to begin to flower. Most cottonwoods don’t live past 200 years, but in those 190 years of flowering, they produce billions of cottony seeds that drift through the air just like it was snowing in the summer.
The cottonwood tree was an important tree to the Lewis and Clark expedition. When Lewis and Clark determined they needed to portage around the great falls on the Missouri River, they used rounds of cottonwood trunks to make wheels and axles. Cottonwood was also used to make dugout canoes that the expedition used on the Missouri River and provided shelter during the long, arduous trip.
Black cottonwood was common throughout the Columbia River watershed in Lewis and Clark’s day, as it still is today. Lewis made note of it in his journal on July 2, 1806, while the party was at Traveler’s Rest in western Montana.
Economic uses of the Black cottonwood include lumber and the manufacture of wood products such as paper. It is known as a good light wood. The wood is also used for fuel. The resin is used in medicine and perfume.
Enjoy Boundary County and all its beautiful trees.