One of the interesting aspects of working under trees is all the different stuff that falls on your head. Everybody sees snow, rain , sleet, hail. Its hard to miss autumn leaves, maple helicopters, or the petals from cherry trees. Sometimes whole trees fall, or branches; that is usually bad. Large populations of caterpillars, gypsy moth or tent, eat and metabolize so fast that there is a constant rain of their fecal exudate. That is gross. When we first moved to the Adelphi house there was a metal awning over the small front stoop, itself under two large cherry trees. Tent caterpillars love cherry trees. At the height of the season you could stand under that roof and listen to the defecation sift down onto the metal. Like fine sand. A lot of it. We cut the trees down in our third year in the house. Sometimes the caterpillars themselves, fall and it doesn't seem to bother them; they just crawl back up the tree and resume eating and pooping. Cankerworms, or loopers (those tiny green or brown inchworms), drift on short lengths of spun silk, riding the wind to new meals. I swear that Blue Jays deliberately drop acorns on my head in the fall but its probably not true. It sure seems that way though. If you look up, keep your mouth closed!
When parts of trees (petals, flowers, seeds, bracts, sepals, bud scales) fall, they usually do so over a short period; sometimes less than a day, almost always less than a week. They fall always at a particular season and often as the result of a particular stimulus, usually a weather phenomenon. Plant parts falling out of trees were often "pushed off" by a sudden increase of turgor pressure. White Oaks hold their leaves all winter and often the stimulus to lose them is a rain that swells up twigs and pushes the leaves off.
The beech tree bud scales in this picture fell a week and a half ago. Joan and Jeanna were there. I missed it I am sorry to say. Maybe next year, though I don't remember ever seeing them all fall at once before; this may have been a once in a lifetime chance. Oh well. Last year was the first time I ever remember hearing/feeling the rain of tiny seeds from gumballs, the fruit of Liquidambar styraciflua. Since they fall in the autumn they make a distinctive sound as they cascade onto dry leaves on the forest floor. Theres always something exciting going on in Fern Valley.