Meadowlark is alive. That was obvious from the moment we walked in the door.
March 8, 2019
We soon will lose our summer umbrella of living shingles: the marvelous evolutionary development we call the green plant leaf. In addition to the leafs' essential process of photosynthesis, they offer shade to plants, animals, and soils in thousands of different ways.
But leaves, even on conifer trees, are temporary structures. For deciduous trees, we celebrate this ephemerality by looking forward to the change in leaf colors—our palette of fall--knowing full well that color change is related to leaf drop and death.
Several factors influence fall leaf color: increasing night length, lowering air temperatures, distribution of leaf pigments, and genetics. Genetics determine why leaves or fruits of certain species turn certain colors. But the astronomically-based trend of steadily longer nights during fall is the big unvarying factor in the equation. Color intensity is enhanced by ample rainfall and by steadily falling air temperatures, but is impeded by suddenly freezing temperatures.
The green pigment, chlorophyll, during the growing season, constantly is being produced and broken down within leaves, but chlorophyll production slows down and eventually stops as nights lengthen and temperatures drop. And other existing pigments are unmasked. The carotenoid pigments, present along with chlorophyll during the growing season, produce the yellow, orange, and brown pigments we see in some leaves and in corn, buttercups, carrots, daffodils, rutabagas, and bananas.
The anthocyanin pigments, most produced in leaves as days shorten and nights lengthen, give their colors to some leaves and to cranberries, red apples, blueberries, plums, Concord grapes, cherries, and strawberries. Genetics play the big role of determining the combination of carotenoid and anthocyanin pigments present in both ripe fruits and in the changing colors of leaves.
Many marvelous processes are in progress as plants and animals prepare for the cold, but one of the most obvious, and most beautiful, is that process by which trees and shrubs shed their most vulnerable parts: leaves—that will be broken down over the winter by microbes into compounds and elements that can, in turn, be used for building by both plants and animals. The cycle continues!
Our palette of fall!
Gently falling, fading—gone,
Save in grateful eyes.
Haiku poem by NJB
2121 Meadowlark Road
Manhattan, KS 66502