WHAT MAKES LEAVES FALL?
In early autumn, in response to the shortening days and declining intensity of sunlight, trees begin the processes leading up to their baldness (no PC emails; I’m follicly challenged myself). The veins that carry fluids into and out of the leaf gradually close off as a layer of cells forms at the base of each leaf. These clogged veins trap sugars in the leaf and promote production of anthocyanins. Once this separation layer is complete and the connecting tissues are sealed off, the leaf is ready to fall. As autumn begins to yield to winter, the colors fade and the stems binding leaf to tree branch begin to weaken. Before long, the leaves are literally hanging by threads–the tiny arteries that brought them water and glucose during the summer. Fall’s winds, leaf pickers, wild animals, almost anything that brushes up against them snap them off the tree. Fortunately, the colors remain after the leaves have dropped, but only for a day or so, so if you want to collect and press them, you ca
