Day Length and Flowering Plants
Paragraph 1：Most trees change with the seasons. Deciduous trees lose their leaves as winter approaches (or, in the seasonal tropics, as the dry season approaches) and enter a state of dormancy. This is not a simple shutting down. Dormancy takes weeks of preparation. Before trees shed their leaves, they withdraw much of the nutrients within them, including the protein of chlorophyll, leaving some of the other pigments behind to provide at least some of the glorious autumn colors; and to conserve water, they stop up the vessel ends that service the leaves.
