" The quaking aspen takes its name from its leaves, which react to the slightest breath of wind. And although we have sayings that associate this characteristic with fear (“to shake like a leaf”), quaking aspens don’t shake because they are afraid. Their leaves hang from flexible stems and flutter in the breeze, exposing first their upper and then their lower surfaces to the sun. This means both sides of the leaf can photosynthesize. This is in contrast to other species, where the underside is reserved for breathing. Thus, quaking aspens can generate more energy, and they can grow even faster than birches. "

― Peter Wohlleben , The Hidden Life of Trees: What They Feel, How They Communicate: Discoveries from a Secret World