Today is the first day of “Autumn,” a word that reportedly originated from ancient words for “cold” and “to cool off.” In the United States, you more likely would hear that today is the first day of “Fall,” referring to a time when the leaves of deciduous trees and bushes turn color and fall. Some of our trees and bushes started to change weeks ago. Here we see the leaves of what we think is a small Mountain Maple (Acer spicalum) near our pond.:
The trees and bushes feel the cooling and lessening of sunlight as a signal that they must conserve moisture and reduce the amount of energy that they consume to survive the oncoming winter. They do this by ceasing to make food for themselves.
As we understand it, this process breaks down the leaves’ green chlorophyll pigment that is used for turning the sunlight into food and oxygen (photosynthesis). That breakdown allows human eyes to see the other pigments – yellows, oranges, reds – many of which already were in the leaves, but were masked by the abundance of green.
Below, you’ll see the leaves on one of our Viburnum bushes (Viburnum plicatum, we think), which contains dark and light purple, as well as reddish and green leaves at this moment:
It will be interesting to see whether this Autumn/Fall of 2021 is any different throughout the country due to the various effects of Climate Change. (Images taken in Brooklin, Maine, on September 20, 2021; quoted title of song by Bob Dylan.)