New England is one fire this week. Not like the fires we saw this summer out West, something much more benign. The vivid autumn palette of reds, oranges, and golds outside our window inspires art, song, poetry, melancholy, hope and if we’re lucky, great soups. Whether you love or hate this particular season of change, you must admit its beauty can be a knock out. But how does it happen? Why the autumn colors?
Three things are at work here: leaf pigments, increasing length of night, and the weather. There are three types of pigment in leaves: Chlorophyll, necessary for photosynthesis, feeds leaves and gives them their basic green color; Carotenoids responsible for yellow, orange, and brown colors; and Anthocyanins which give colors such as those we find in cranberries, red apples, concord grapes, blueberries, cherries, and plums.
During winter in these climates, there is not enough light to support photosynthesis and the sweet greens of summer go dormant. As the Chlorophyll of photosynthesis breaks down, the greens fade and other pigments, present in small quantities in the leaves all the time, shine through. As these colors appear, cellular changes are also taking place within the leaves causing each leaf’s point of attachment to the tree to weaken and sever. Et voila. Fall.
It’s not so romantic when you look at the science of it. But take a look outside. You might just find some inspiration there.
“After Apple-Picking” by Robert Frost
My long two-pointed ladder’s sticking through a tree
Toward heaven still,
And there’s a barrel that I didn’t fill
Beside it, and there may be two or three
Apples I didn’t pick upon some bough.
But I am done with apple-picking now.
Essence of winter sleep is on the night,
The scent of apples: I am drowsing off.
I cannot rub the strangeness from my sight
I got from looking through a pane of glass
I skimmed this morning from the drinking trough
And held against the world of hoary grass.
It melted, and I let it fall and break.
But I was well
Upon my way to sleep before it fell,
And I could tell
What form my dreaming was about to take.
Magnified apples appear and disappear,
Stem end and blossom end,
And every fleck of russet showing clear.
My instep arch not only keeps the ache,
It keeps the pressure of a ladder-round.
I feel the ladder sway as the boughs bend.
And I keep hearing from the cellar bin
The rumbling sound
Of load on load of apples coming in.
For I have had too much
Of apple-picking: I am overtired
Of the great harvest I myself desired.
There were ten thousand thousand fruit to touch,
Cherish in hand, lift down, and not let fall.
That struck the earth,
No matter if not bruised or spiked with stubble,
Went surely to the cider-apple heap
As of no worth.
One can see what will trouble
This sleep of mine, whatever sleep it is.
Were he not gone,
The woodchuck could say whether it’s like his
Long sleep, as I describe its coming on,
Or just some human sleep.