Plants Picked on December 1st, Central Park (Click to enlarge)

New England has the most beautiful fall colors in the world. Autumnal changes in leaf color are brought on by the decay of the dominant pigment chlorophyll, which allows other hidden colors in the leaf to come out. The different pigments have interesting medicinal and chemical properties.

            Oaks have brown tannins, used in tanning leathers. Red anthocyanins are one of the healthy components of red wine; blue anthocyanins of blueberries; carotenes of carrots; betacyanins of beets.

              Senescence is the process by which cell components and membranes die. Abscission is the process by which leaves fall. The exact cause of chlorophyll breakdown is not known, and nobody really knows what brings on senescence or abscission either; one hypothesis is that they are brought on  by hormones. Other factors may include gradual reduction in day length, lowering temperatures, light intensities, or lack of water. In my next post, I will discuss my interview with a climatologist about changing weather patterns and the potential effects on plant internal clock cycles.