Some trees have dropped their leaves instantaneously, as at a signal.

October 17. 

Notice some of the fungus called spunk, very large, on the large white oak in Love Lane, eight or nine feet from the ground on the east side, on a protuberance where a limb was formerly cut off. It is now green and moist, of a yellowish color, composed of several flakes one above the other; the length of the shelf, or chord of the arc, twenty-one inches; depth from the tree, or width of shelf, about one foot. 

Frost has now within three or four days turned almost all flowers to woolly heads, — their November aspect. Fuzzy, woolly heads now reign along all hedge rows and over many broad fields. 

Some trees, as small hickories, appear to have dropped their leaves instantaneously, as at a signal, as a soldier grounds arms. The ground under such reflects a blaze of light from now crisped yellow leaves. Down they have come on all sides, as if touched by fairy fingers. 

Boys are raking leaves in the street, if only for the pleasure of dealing with such clean, crisp substances.

Countless leafy skiffs are floating on pools and lakes and rivers and in the swamps and meadows, often concealing the water quite from foot and eye. Each leaf, still crisply curled up on its edges, makes as yet a tight boat like the Indian's hide one, but ere long it will be come relaxed and flatted out and sink to the bottom, i. e. if it is driven out to sea, but most are drifted toward the shore, which is converted into one long, crowded haven where the water is concealed, and they settle close to land.

Many fringed gentians quite fresh yet, though most are faded and withered. I suspect that their very early and sudden fading and withering has nothing, or little, to do with frost after all, for why should so many fresh ones succeed still? My pressed ones have all faded in like manner! ! 

It would be too late to look for bees now at Wyman's; the flowers are too far gone. 

I go down the path through Charles Bartlett's land. The young white oak leaves are now generally withered in and on the sides of the hollows there, also the black scrub, while the red and black oaks are still commonly red and so far alive. 

As I stand looking at Emerson's bound under the railroad embankment, I heard a smart tche-day-day-day close to my ear, and, looking up, see four of these birds, which had come to scrape acquaintance with me, hopping amid the alders within three and four feet of me. I had heard them further off at first, and they had followed me along the hedge. They day-day 'd and lisp their faint notes alternately, and then, as if to make me think they had some other errand than to peer at me, they peck the dead twigs with their bills — the little top-heavy, black-crowned, volatile fellows.

H. D. Thoreau, Journal, October 17, 1856

Some trees, . . have dropped their leaves instantaneously, as at a signal, . . .The ground under such reflects a blaze of light from now crisped yellow leaves. See October 15, 1853 ("They suddenly form thick beds . . . just the size and form of the tree above.")

Countless leafy skiffs . . . concealing the water quite from foot and eye. See October 11, 1857 ("Another frost last night, although with fog, and this afternoon the maple and other leaves strew the water, and it is almost a leaf harvest."); October 12, 1855 ("The leaves fallen last night now lie thick on the water next the shore, concealing it, —fleets of dry boats . . ."); October 12, 1858 ("There are many maple, birch, etc., leaves on the Assabet, in stiller places along the shore, but not yet a leaf harvest"); October 13, 1860 ("Now, as soon as the frost strips the maples, and their leaves strew the swamp floor and conceal the pools, the note of the chickadee sounds cheerfully winteryish."); October 15, 1856 ("Large fleets of maple and other leaves are floating on its surface as I go up the Assabet. . ."); ;October 17, 1857 ("The swamp floor is covered with red maple leaves, many yellow with bright-scarlet spots or streaks. Small brooks are almost concealed by them. "); October 17, 1858 ("They remind me of ditches in swamps, whose surfaces are often quite concealed by leaves now. The waves made by my boat cause them to rustle, "); October 19, 1853 ("The leaves have fallen so plentifully that they quite conceal the water along the shore, and rustle pleasantly when the wave which the boat creates strikes them."); October 22, 1853 ("this great fleet of scattered leaf boats, still tight and dry, each one curled up on every side by the sun's skill,"); November 1, 1852("On the river this afternoon, the leaves, now crisp and curled, when the wind blows them on to the water become rude boats which float and sail about awhile conspicuously before they go to the bottom.")