An Autumnophile

Just  outside our kitchen window we have a small lawn, though using the word ‘lawn’ to describe it is stretching the imagination somewhat; there are more weeds in this patch of green than anything else. On the edge of this uninspiring garden feature there is a sweetgum tree. The tree is old, and showing it’s age by shedding branches, which upsets me as I happen to love the tree. Despite its infirmity the sweetgum provides dappled shade in the summer, and in the fall it turns into a utterly gorgeous work of art that delights me every year. 

Where I grew up there is not much of a fall; there is a hot season and a not hot season. Winter is cool and sometimes damp, spring is short but beautifully celebratory, and autumn is like a damp squib; in short nothing much happens. 

I have lived in places where fall occurs every year for a while now, and yet I still get ridiculously giddy when leaves start to turn colors. It still feels like some kind of magic is in the air when our sweetgum tree leaves turn gold and then red. 

What makes this magic take place? Plants have small energy making factories in their cells that are called chloroplasts. Most of these can be found just below the outer layer of leaves in the parenchyma tissue. These green colored chloroplasts serve the same purpose in plants as the mitochondria do in our cells. 

The chloroplasts use the red and blue wavelengths in light, along with carbon dioxide and water, to create the sugars that the tree needs to live. The unused green light wavelength "is then reflected to our eyes as we reflect on nature's beauty. Green means the tree is alive and sucking in red and blue energy." 

In the heat of summer trees will shrink their leaves and the chlorophyll particles get broken up. As a result, red light is not absorbed as much but is reflected instead, and when combined with green it gives us the yellow leaves of late summer and early autumn. Later in the year, carotenoid pigments, which are always present in leaves  come to the fore, which is when we see more yellow leaves, as well as some that are orange and brown.  

As it gets colder the sugary sap that feeds trees is not able to flow as freely. It is time for the tree, like many animals, to store food and take a rest. Using a substance called anthocyanin, which is red or purple in color, the tree withdraws all the useful things in the leaves, and it isolates the leaf from the rest of the tree by producing cork cells at the base of the leaves. When it freezes the cork cells break down, the leaf snaps off, and it drifts down to the ground.

We can see the town of Ashland from our farm and as the temperatures finally start to drop the trees in gardens and medians turn flaming red (maple), yellow (aspen and big leaved maple), russet (oak), gold (black cherry), and burgundy (dogwood). We can watch as one after another tree species starts withdrawing the precious green chlorophyll from its leaves, leaving behind the colors that turn people such as myself into wide eyed oohing and aahing fall addicts. 

Is it just the colors and cooler temperatures that make fall such a loved time of year? Psychologists think that there is more to explain this autumnophilia. For many adults fall is a time for a fresh start, perhaps because the season was, for many years, associated with the beginning of a new school year. For many of us a new school year meant new clothes, brand new school supplies (with the perfume of freshly sharpened pencils), new friends, and a new teacher. In short, it was a time when there was a feeling of promise and excitement in the air, and this feeling still persists year after year long after the text books and pencil cases have been retired. 

Autumn is also a time when we reconnect with home, family, friends, and routine, after the relative chaos of the summer holidays. It is a time to go for walks to admire the fall foliage, and then snuggle down under a cozy blanket to watch a film or read a book. 

Ashland in the fall - Photo by Sean Bagshaw