Why the Blue Ridge Mountains are… Blue



Living in the Blue Ridge Mountains of Southwest Virginia for nearly my entire life, I have always been fascinated by the fact that from a distance, the Blue Ridge Mountains actually appear to be…wait for it… Blue.  This phenomenon is even more interesting when one nears the majestic blue mountain ridges only to discover what was at first a mountain whose colors covered the entire spectrum of blue has magically turned completely green upon second inspection.

Early settlers were so impressed by this haunting mountain chain, which seemingly had the power to change its color at will, and at multiple times throughout the same day, that they renamed the geologic formation from its Native American title of Quirank to Blue Ridge Mountains.  In recent decades, the mountains have been romanticized around the globe thanks to the likes of Dolly Parton and John Denver.

Though early pioneers struggled to understand why the mountains appeared blue from a distance and some even attributed various superstitions to the natural marvel, scientists have now been able to crack the mystery as to why the Blue Ridge Mountains appear as they do.

Rather than going deep into the weeds and breaking down the mind numbing CH2=C(CH3)−CH=CH2 chemistry equation, we’ll make this edible for common folks — the trees and other plant life blanketing the ancient mountains emit a compound known to scientists as isoprene.

Isoprene emission are a natural survival mechanism trees use in order to combat naturally occurring stresses plants in the Appalachian region face — often on a daily basis — which includes large fluctuations in leaf temperature. Isoprene is incorporated into and helps stabilize cell membranes in response to heat stress.

Upon being released, isoprene interacts with other molecules in the air, creating the distinctive haze that’s come to distinguish the Blue Ridge Mountain range from so many others around the globe; it’s not that trees in other places don’t emit isoprene, but they typically do not release the chemical in as high of a rate as trees in this particular region of the country do.

The result is that the mountains appear much like the sky or ocean from a distance: soft blue.

Interestingly, Central Appalachia is not the only place on the planet where the extreme stresses of the environment have created mountains that appear blue from a distance.  Australia’s Southeast province of New South Wales is home to the Blue Mountains which appear quite similar to the Blue Ridge Mountains of Appalachia from a distance for the very same reason.

In short, the 550-mile stretch of the Blue Ridge Mountains which have become world famous and reach into eight separate states are possible thanks to microscopic chemical reactions no one could ever see with their naked eye!

Like articles like this? Then you would love Appalachian Magazine’s Mountain Voice: A Collection of Memories, Histories, and Tall Tales of Appalachia!  Click here to check out the book on Amazon!

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