It fascinates me that a leaf knows when its time has come to fall. Perhaps some combination of day length and temperature gives the signal. But maybe it’s just the good taste to abort, an inner sensitivity to the needs of the whole that gives its parent tree a chance to hibernate with its blood gone underground for the winter, safe from freezing. Whatever the signal for the moment of leaf launch, I’m glad they don’t all get the same idea on the same day.
First, the walnut and basswood and spicebush leaves fly in the first winds of tropical storms or sudden thunderstorms in late summer. The poplars and hickories, cherries and sumacs have the good manners to wait a while, until after a leaf has had the proper opportunity to strut its chameleon color changes during October before finally falling, drab and shriveled, in a north wind on a bleak November day.
An oak leaf will refuse to let go until December, clacking and waggling brown and brittle in the cold breeze. The serrated leaves of a smooth-boled American Beech turn almost white and become so thin and light they hang like feathers and seem to move on their own, even on a still January day. This year’s beech leaf may stay on the twig until next spring’s tiny new leaf evicts it, finally, pushing it out and away, off into space, down to the black soil among the first of the spring mustards and violets.
Leaves enter my fantasies this time of year. I have wondered about them, individually, and as a race. If all of the leaves from the countless trees on our acres here fell and did not decompose by the following spring; if this happened year after year, how many years would it take to choke off all growth along the forest floor? Should our woods remain alive after even one year of such a calamity, which is doubtful, how many years of leaf-fall would it take to completely fill the bowl of our valley to the rim?
If all these same leaves from our small valley could by some fairy-industry be stitched together, edge to edge, would it make one huge leaf, big enough to dress all of the New River Valley or Virginia?
And if a curious person was to lie on his back in these woods for a day, could he learn to tell all the leaves to species merely by the pattern of their falling from the tree when the air is still? My hypothesis is yes, and I gladly volunteer to undertake the research.