Brilliant leaves swirling in the breeze, crunching beneath your footstep, creating a vibrant, scented quilt to warm and replenish the earth. Fall is a season of new beginnings and celebration. School days, Halloween, and Thanksgiving beckon us to follow tradition and be grateful. While many of us are marching to a faster tempo, trees are in the beginning stages of rest and that means colour. With the advent of shorter days and less than adequate sunlight, leaves halt chlorophyll production (green pigment) and as it fades yellows and oranges become visible. Yellow and orange pigments have been there all along, masked by the cool greens of summer. This process is somewhat like us going grey, without the blaze of colour! The brilliant red of the maple is a result of glucose trapped within the leaf as the warm days rapidly decline into cooler evenings. Fortunately for us there is enough sugars within the tree to tap maple syrup! The brown leaf of the oak is really just waste materials such as tannin, while not as beautiful to behold, provides us with the distinct smell of autumn candle manufacturers try, but can never succeed in re-creating.
Anti-oxidants contribute to the leaf colour, xanthophyll for yellow, carotene for orange, and anthocyanin for purples. It would seem antioxidants are good for all!
If you are not fond of raking leaves (and especially if you are), be advised that decomposed leaves restore soil nutrients, hold moisture, and feed beneficial soil organisms so you can either shred them into mulch (best) or let them lie as they will (good). Either way is a win.