By James McGuire

Contributing columnist

Falls’s full-dress extravaganza is at our door — literally!

I’ve watched autumn’s leaf-show spectacles come and go for decades, made notes, and concluded our annual color peak occurs around Oct. 20-25.

Both my observations and journal jottings agree with this timeframe—though I do exclude those little micro-climate areas that operate on their own schedule.

While light plays a greater part than weather in triggering leaf change, here along the river, leaves on several species of trees often remain green longer—or at least lag behind in the speed of their palette revealing—than leaves on similar trees a few hundred yards up the hill, away from the water’s ameliorating influence.

Of course, what I view and think of as the local color peak, and what you’d pick as that same point, is completely subjective—a personal and likely idiosyncratic. I admit to a bias for swamp maples and black gum. While not quite on par, I also think flaming red oaks are pretty spectacular.

When those blazing blood-reds begin the fade, I consider the color-peak to be past and waning.

This also gives the whole autumnal color show a sort of bookended symmetry since fall’s first hint of color typically onsets with the unexpected brilliant red of sumac—a few scarlet leaves startling the green monotone.

Soon you start to notice whirls of maroon woodbine twining in cool flame up the trunks of roadside trees.

Hickories go a rusty saffron. Walnuts become lemony.

Finally, the little sugar maples chime in with snatches of orange and yellow and red—colors so bright and lively they seem filled with inner light.

Embers have now kindled to flame, in a deliberate process of nuances and degrees.

Once the fire is lit, the color increases until, by mid-October, local woodlands are a patchwork of red and gold, orange and burgundy, yellow and amethyst—plus assorted shades of beige, ruby, lemon, vermilion, hazel, and salmon.

Some trees sport multi-colored leaves—edges one hue, centers another. Or a leaf might be crimson, while another on the same branch is maroon or scarlet

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The variations are endless. Colors beyond names!

What causes this wondrous multi-hued pageant?

Native Americans from the upper Great Lakes region tell of a time when earth and sky were more connected. They recount the day when a roaming band of brave and skilled spirit hunters managed to stalk and slay the Great Bear of the heavens—the most respected of all their animal brothers.

But this mighty bear didn’t succumb easily. The battle was fierce. Blood rained down from heaven, turning October’s leaves various tones of red.

The victorious hunters then built a huge fire and began to roast their prize for a celebratory feast. Fat from the cooking spattered and dripped to the earth below, turning other leaves different shades of yellow and orange.

Alternatively, you might prefer the legend of Jack Frost. The tale’s roots lie in European folklore but is nowadays reduced to the caricature of a rather fey elf mincing about during the night, dabbing his dripping paintbrush hither and yon.

The scientific explanation is, unfortunately, rather more prosaic, exciting only to a botanist or chemist.

All leaves, big or small, are basically sophisticated factories whose job is to convert sunlight into energy—done via the process of photosynthesis. Leaves contain chemical compounds called chlorophylls. Chlorophylls not only give leaves their green color, they also absorb light which allows plants to transform carbon dioxide and water into oxygen and carbohydrates.

Chlorophyll compounds, however, aren’t very stable, so plants must continually synthesize a supply. So long as there’s plenty of sunlight, everything is fine. Water and nutrients rise from roots to branches into leaves. Sugar and starch carbohydrates produced by photosynthesis are carried along, feeding the tree and producing growth.

Then days begin to shorten. The fancy word for the length of daylight is “photoperiod.” Shorter photoperiods interrupt the photosynthesis process. This triggers changes in the tree, the principal one being the growth of a corky membrane between the leaf stem and the branch which chokes off the nutrient flow to the leaf.

Chlorophyll production declines. The green begins to fade — and the color that was there all along is revealed.

How? Because in addition to chlorophylls, leaves also contain compounds called carotenoids, which give them their yellow, orange, and brown hues. Without those masking green chlorophylls, the bright carotenoid pigments suddenly begin to gleam like gold in everything from beeches to hickories to sycamores.

Reds, on the other hand, are byproducts of leaves containing another set of pigment compounds called anthocyanins. Unlike the carotenoids, anthocyanins aren’t present throughout the leaf’s growing season but develop in late summer in the sap of the leaf’s cells.

Anthocyanins thrive on a breakdown of sugars in the leaves. They’re responsible for the reds, maroons, and amethysts of maples, oaks, and sweet gums—all those rich shades that make a patch of forest seem like a panel from an old tapestry.

The balance between carotenoids and anthocyanins is why almost no two species of trees exhibit autumn leaves of exactly the same hue.

So, take your pick! Spirit bear, paint-flinging elf, or botanical chemistry. It all comes down to a sort of natural magic that turns woodlands into a wondrous kaleidoscope of breathtaking hues—the very essence of autumn.

We’ve once again reached autumn’s show-stopper grand finale. The landscape’s stage is filled with brightly costumed performers. Nature’s technicolor kickline is dazzling as it gives us a flashing seasonal send-off.

Don’t miss this color peak!

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