The light received by a tree is the sum total of all its unshaded surfaces. Even shaded leaves receive light, although they operate at far lower intensities.
Chinese Elm Shows the Way
They are, in effect, at rest, conscious but dreaming. When you sleep under a tree, you enter this energy. When those leaves rustle in the wind, they actually are speaking. These are not metaphors. Breath rises and falls… imagine, entering the breath and dreams of another creature!