Fall, in the astronomical sense, lasts as long as all the other seasons. However in the dendrological sense it seems to be the shortest on the seasons, lasting only a few weeks.
The green of summer lingers well into the first couple weeks after the sun drops below the equator with little change expect fewer, and different wildflowers. Then in the first week of October leaves dismantle the chemical foundation of their solar collectors and brilliant hidden hues appear.
In a short span of a week, at most a couple of weeks, the whole of the forest canopy shifts from green to red, orange, scarlet, gold, maroon, bronze, and other seasonal colors. Just when the color reaches a peak the leaves lose their grip on the twig and float slowly to the ground.
Along the Great Allegheny Passage the drifting flats of color land on a neutral gray limestone canvas until the trail is are brightly and abstractly colored as the canopy. But the finished work on the trail is
as transient as was the canopy and soon the leaves are uniform brown, crisp, and beginning to be ground into dust.
At the end of the weeks the forest is now more winter, a state it will continue until well into May. Fall seems to give up trying as soon as it starts and gives over its days to the coming cold.