in Thoreau’s Journal:

In Lee’s Wood, white pine leaves are now fairly fallen (not pitch pine yet), —a pleasant, soft, but slippery carpet to walk on. They sometimes spread leafy twigs on floors. Would not these be better? Where the pines stand far apart on grassy pasture hillsides, these tawny patches under each tree contrast singularly with the green around. I see them under one such tree completely and evenly covering and concealing the grass, and more than an inch deep, as they lie lightly.

These leaves, like other, broader ones, pass through various hues (or shades) from green to brown, —first yellow, giving the tree that parti-colored look, then pale brown when they fall, then reddish brown after lying on the ground, and then darker and darker brown when decaying.