What does the tree say? The OED notes of psithurism, “Obsolete. Forms: α. psithurisma. β. psithurism. This word belongs in Frequency Band 1.
Band 1 contains extremely rare words unlikely ever to appear in modern text. These may be obscure technical terms or terms restricted to occasional historical use, e.g. abaptiston, abaxile, grithbreach, gurhofite, zarnich, zeagonite.

a rustling or whispering sound, such as leaves in the wind; susurration: “Standing in the glade I heard a quiet psithurism, just straddling the line between music and noise.”


sycamore leaf frost
A plant will abscise a part either to discard a member that is no longer necessary, such as a leaf during autumn, or a flower following fertilisation, or for the purposes of reproduction. Most deciduous plants drop their leaves by abscission before winter, whereas evergreen plants continuously abscise their leaves. Another form of abscission is fruit drop, when a plant abscises fruit while still immature, in order to conserve resources needed to bring the remaining fruit to maturity. If a leaf is damaged, a plant may also abscise it to conserve water or photosynthetic efficiency, depending on the ‘costs’ to the plant as a whole. The abscission layer is a greenish-grayish color.–Wikipedia


numbered rocks
Sufferers may for instance feel compelled to count the steps while ascending or descending a flight of stairs or to count the number of letters in words. They often feel it is necessary to perform an action a certain number of times to prevent alleged calamities. Other examples include counting tiles on the floor or ceiling, the number of lines on the highway, or simply the number of times one breathes or blinks–Wikipedia