As fall sets in, trees start preparing for the cold weather. The winter is too cold for most biological functions to continue and the trees will shed those leaves that were so productive during the warmer seasons. However, it would be wasteful to lose those nutrients and essential molecules still lodged in the leaves.
As temperatures cool, chlorophyll production in deciduous trees tapers off and the existing chlorophyll within the leaves starts to break down into simpler compounds. Resorption involves the extraction of nitrogen, a vital but limited resource, from the chlorophyll molecule. Sugars are also stored. These nutrients are stored in the parenchymal cells of the wood and bark.
The process of leaves separating from tree branches is called abscission from the Latin ab meaning “away” and scindere meaning “to cut.” While we are intuitively familiar with this process in the fall, it operates under other conditions also such as when a blooming flower is discarded after fertilization occurs since it has fulfilled its function.
Good reading for a cold snowy winter day! Thank you.