It is close to the end of October as I write this column, and the days are getting colder and shorter. Flocks of migrating Canada geese will be in the sky; if they are not seen, they are heard by their honking.

The first buffleheads, tiny black-and-white ducks, will be visible on the region’s waterways around Halloween, as they migrate down from Canada.

No doubt about it, fall is here.

Fall was, and still is, known as autumn, short for the autumnal equinox. The word “fall” apparently became popular in England in the 1600s; it is short for “falling leaves.”

Most of us already have a fair amount of fallen leaves in the yard or driveway, and the sound of leaf blowers can be heard.
In the driveway this morning, I had lots of black birch leaves (yellow in color and the first to be seen on the ground), yellow and red maple leaves, yellow chestnut oak, and a few sassafras leaves, along with isolated red and white oak leaves. They are the last to come down and comprise the bulk of the mixed forest that surrounds my home.

The reward of having to remove a lot of leaves is seeing them while still on the trees in their vibrant fall colors.

With the colder temperatures, the production of chlorophyll (the green compound that is necessary for photosynthesis) slows down and then stops. The lower levels of chlorophyll in leaves allow other compounds, which are always present, to show through during this time. Depending on the species and weather, compounds like carotenoids (yellow) and anthocyanins (red and purple) will be present for a few days to a week or more. The color disappears when the compounds break down.

Leaves fall from the tree in a process called abscission: a protective layer is formed between the leaf and the twig of the tree and causes the leaf to detach.

As our earth circles around the sun, giving us the seasons, I think about the circle of life: animals preparing for hibernation, others on long migrations, and most insects reaching the end of life, their young in eggs prepared to overwinter the few months until the renewal of spring.

As the last of the lettuce and other crops are harvested, we celebrate the burst of color during this season before winter snow covers the landscape. We see a red squirrel adding to its secret stash of acorns, and then gaze out and watch the falling leaves.