History of the Aspens


Every year about this time, Fall is ushered in by a flush of Aspen trees as their leaves turn to gold. Where I live in the Rocky Mountains of Colorado, the particular aspen is called the “trembling” or quaking aspen. The broadleaf and flattened stem cause them to flutter in the breeze. It is a type of poplar tree called populus tremuloides. As tourists visit New England in Autumn for Leaves and Lobsters, visitors come to Colorado to Leaf Peep as the aspens change to dramatic yellows, golds, and reds.

Aspen Yellow


Aspens: Send in the Clones

Aspens front

Aspens snow


In the Roots of Aspens

Aspen Valley

An aspen tree may die, but the root system remains intact, sending up replacements nearby. In this way, a grove may survive a large forest fire and is very hardy. The trees themselves are subject to a variety of diseases and insects. They rarely last more than 25-40 years in urban settings, and half a dozen have died on my property while I’ve lived there for over three decades. However, in forests at higher elevations, they may live almost ten times that length, and the root system may live longer still.


Spreading Aspens

Pando Aspens

Many colonies grow larger from year to year, spreading over acres of land. In Utah, the oldest known colony, named Pando (“I spread”), is reported to be thousands of years old. Fishlake National Forest, on the western side of the Rocky Mountains, has one of the largest organisms in the world in terms of both volume and mass, measuring 107 acres and 6,000 tons.

For you shall go out in joy and be led forth in peace;
the mountains and the hills before you shall break forth into singing,
and all the trees of the field shall clap their hands.
-Isaiah 55:12


Bill Petro, your friendly neighborhood historian

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About billpetro

Bill Petro has been a technology sales enablement executive with extensive experience in Cloud Computing, Automation, Data Center, Information Storage, Big Data/Analytics, Mobile, and Social technologies.


  1. great article and will look forward to more! :)+

  2. Thanks Bill!

  3. …and what is not commonly known, is that aspen leaves are always golden/yellow. In the spring and summer, however, the yellow is not visible because it is covered over by the green of the chlorophyl. In the fall, when the leaves stop producing chlorophyl, the green lightens and fades away, gradually revealing the yellow that has been there all along. 🙂 With the right equipment, you can make an aspen leaf “turn” yellow in the lab.

  4. I learned my new thing for the day. World’s largest organism… Neat stuff! Thanks! 🙂

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