[NOTE: This essay was originally published in the Pekin Daiy Times online in May 2012.]
Early last Sunday morning, I went to my cabin along the Illinois River bluffs for an early breakfast and to enjoy the cool breezes on the screened-in front porch. The screens usually need cleaning every so often from filtering the winds of whatever light debris is aloft. But on this day, the screens were exceptionally filthy. And I knew why: downy seeds from the eastern cottonwood.
May is the month when cottonwood trees release their seeds, which are distributed across the land by winds. The seeds have the best chance for germinating when they fall on bare ground. And the seedlings grow best under full sun, with no competing vegetation. Because most of the land is already occupied by vegetation of one type of another, the chances of finding suitable bare ground would seem to be low. But here is where the Illinois River plays a role.
The Illinois River’s yearly flood cycle is more or less predictable in a general way, and cottonwoods have adapted to that cycle. On average, its waters, over several weeks, gradually rise toward a high water level, or flood, sometime in mid-spring, according to previous records. When the waters recede, bare ground may be left behind. And if events are timed just right, that will be the same time that cottonwood seeds are falling. The floodwaters can also carry waterborne seeds to other areas along the river’s floodplain.
An eastern cottonwood, in fact, is supremely adapted to having its base covered in floodwaters for extended periods. While an upland tree such as black oak would never survive on the Illinois River’s floodplain, a cottonwood is quite at home, and forms a valuable component of the forests.
Cottonwood is a very fast-growing tree, but short lived; a cottonwood 60 feet in height might only be fifteen years old; and a specimen older than 125 years would be very unusual. At such an age, the heartwood may likely be rotted with numerous hollows, but useful for shelter and nesting by a variety of wildlife. In addition, the great heights attained, perhaps 100 feet, are attractive as nest trees and perches for bald eagles. Resting eagles are a common winter sight in the tall cottonwoods at my cabin.
So with just a little thought, I am reminded there is more to having cottonwoods on my property than cleaning the porch screens.