The Vivacious Autumn Leaf Colors And The Secret Behind Them

“We won’t last but our brief forever will be a sight to see, like the autumn leaf colors.”

Perhaps nothing ages as gracefully as nature itself. The senescence of gorgeous greenscapes into what is popularly known as fall foliage is a sight to behold as the leaves ripen into the most breathtaking shades of red, orange, purple and brown before ultimately succumbing to the bite of winter. 

The autumnal tints are no doubt the prime attraction of the season, beckoning people to leave the cozy comfort of their homes for the glorious sight that nature is, holding its breath before its final plunge. Braving the cold for leaf peeping, we are tempted to treasure these hues however we can, in photographs, fall makeup, wardrobe, etc. The colors of fall extend to the barks of trees, fruits and flowers but some are distinct enough to be easily identifiable and have in fact, become synonymous with the season itself, mainly the foliage of hardwood trees like aspen, maple and sycamore.

Some beautiful autumn leaf color words 

The vocabulary of autumn is just as colorful as the foliage it describes. There are myriad shades of red- copper, crimson, scarlet, russet, carmine, carnelian, vermilion, maroon, etc. to closely capture the array of nature’s hues on display in the autumn color palette.

Apart from amber and sepia, there is also a special (and somber) color term to denote the brownish hue of curled up dead autumn leaves- feuille morte- French for ‘dead leaf.’

For the lighter yellows, we have auburn, but more interestingly, there’s gamboge, referring to the intense yellow fall- rarer but so much more delightful in its vivacity.

autumn leaf colors
Source: Chris Lawton on Unsplash

What happens to leaves as the cold approaches? 

With the dipping of temperatures, deciduous plants have to resort to shedding of leaves to protect themselves from an overdose of sunlight. Most autumn leaf colors, then, act as antioxidants to protect the plants against free radical damage. The colors aren’t merely for show but in fact, are chemical compounds that attract the light when the rate of photosynthesis dwindles in the cold temperatures. These hues, then, are actually vital to the sustenance of plants.

Carotenoids- the pigments responsible for color

The autumn leaf colors, chiefly attributed to carotenoids, begin to show with reduced chlorophyll masking. The degradation of chlorophyll also results in greater visibility of other pigments like xanthophyll and beta-carotene present in the leaves. These are largely responsible for the yellow and orange hues of the leaves respectively. The telltale autumn leaf red, however, results from anthocyanin which is only synthesized once a certain amount of chlorophyll has degraded. 

yellow-autumn-leaf-colors
Source: Daniel Schludi on Unsplash

The role of autumn leaf colors

There are numerous hypotheses as to why nature puts on this colorful show each year, all the more interesting because research has suggested that there also exist colorless compounds that can perform all of the aforementioned functions as well. So while photoprotection does seem to be the prime reason for this majestic dance, nature, like always, keeps some of its mysteries to itself. 

Anthocyanin is especially known to lend protection from excess light during autumn. Researchers have also discovered that the anthocyanin production in some species of maple is actually increased as part of allelopathy in order to stunt the growth of surrounding saplings. The brilliant shock of copper and crimson results from competition among the plants.

W.D. Hamilton proposed the coevolution theory as responsible for this phenomenon, suggesting that the visual signals are actually warning signs for insects. This is a way for trees to reduce their parasite load.

The vivid colors may also be a tactic to attract birds and insects to aid pollination and conversely, an attempt to render camouflage futile.

Huh, guess we can say nature has a few (colorful) tricks up its sleeves.