Monday, November 4, 2013

Fall Foliage... the Lovely Change

Grandpa's Pond~ Rural Oklahoma.

Perhaps it is said each year, however this year promises the most lovely Autumn in ages. The crisp and divine temperatures of late have Oklahomans happily donning sweaters and getting outside! As the clocks were turned back on Sunday, suddenly the foliage changed and shades of gold and scarlet were seen shimmering in the breezes.

Although the following explanation will be a vast over simplification, it may provide insight into the foliage change. During the spring and summer the trees use their leaves to collect air and water utilizing a process called photosynthesis to turn it into food. Photosynthesis means ‘putting together with light’ so as the days shorten and daylight diminishes, the gathering process ends. The leaf is no longer necessary to the tree and begins its fall transformation and the hillsides become a dramatic autumn palette that provides breathtaking color for a brief moment in time.

The chemicals chlorophyll and carotenoids are present in the leaf cells throughout the growing season with chlorophyll making leaves the bright green color associated with the photosynthesis process. As darkness increases in the autumn, chlorophyll production eventually stops and inevitably all the chlorophyll disappears. With the loss of chlorophyll, the carotids become visible and provide the leaves with lovely yellow colors. Lastly the anthocyanins may arrive and take center stage, ushering in the vibrant reds we associate with Autumn.

Because carotenoids are always present in leaves the amber, yellow and gold colors remain fairly constant from year to year, even during drought. However conditions must be ideal for the fickle anthocyanins who are glucose (sugar) and singularly responsible for the brilliant hues of purple, crimson, and scarlet. To be spectacular the tree requires warm sunny days and cool crisp evenings to slow the closing of the leaf veins and trap an excess of sugar produced at this time. Due to the perfect weather of late, the reds this year are gorgeous.

However the shade and a foliage show are not all the leaves have to offer… their parting gift is perhaps the most important. The leaves drift from the trees and collect below, continuing their work by slowly decomposing. Over time they will add nutrients which create a dark rich soil that nourishes saplings as they grow to become forest giants like their parents. It is indeed a miraculous cycle.

*Note: Many Caddo Maples have changed in an unusual manner this year. The crown of the tree has changed to a brilliant scarlet, the center has changed to an orange, while the lower leaves have remained green. This is very much an oddity.