SciSun: Send in the Clones   Leave a comment

For many people, Autumn is the best time of year, particularly if you live around or near lush forests filled with plants transforming into radiant golds and shocking reds and fire-like oranges. Forests seem to take on every shade of red, yellow and violet among stands of towering oak; groups of dogwoods; collections of willow; and crowds of aspen. Only there is one thing misleading about this scene: While all the other trees and most plants are gathered as individuals, groves of Quaking Aspen (Populus tremuloides) is often just one specimen, each individual tree a clone of all others within its group; which brings the question are the Aspen trees you might find actually one tree with many sprouts; or many trees originating from one system?

Aspens are deciduous trees native to higher elevations with cool summers and generally moist, but not extreme, winters. Reaching about 40 – 100 feet tall, each ‘tree’ (actually individual stems – or aspen ramets – generated from a massive root system) generally lives 50 – 100 years which is a short lifespan for a tree; but the underground root system can live thousands of years and spread many miles. The ‘Pando’ colony (Latin for ‘I spread’) in Utah is estimated to be 80,000 years old; consists of over 47,000 individual ramet stems; covers more than 106 acres; and is probably only a few generations separated from its Aspen-ancestors of millions of years ago, as fossilized leaves of these prehistoric plants, and leaves of modern trees, are virtually indistinguishable. And that, really, is an example of good genes!

Yet while a stand of aspen consists of clones originating from a shared root system (Aspen can also spread by seeds – they’ve got it covered both ways), DNA studies have found that individual specimens from a single population hold more genetic diversity than between specimens of nearby colonies. Which indicates there’s more diversity within a single clone-population, than between two similar populations that may have been spread by seed. So, the seed really doesn’t fall far from the tree, as the saying goes – but that also shows among single populations genetic mutations are occurring that result in unique individuals. And that leads to trees (or stems or ramets – this is all getting rather confusing), that are more suited to survive in changing environments and clone-populations with greater genetic diversity. Or giant mutant trees that will take over the earth.

A mutant-tree invasion aside, how has the mild-mannered Aspen, for decades considered a ‘weed tree’ due to its prolific output of ramets and aggressive colonization, survived while other plants and animals have disappeared? Part of its success is due to the strong, resilient, and generally unique root system (only a few other woody-stem plants, such as the Creosote bush (Larrea tridentata) and Huckleberry (fam. Ericaceae) grow through such a similar clone colony); fire, which can be a disaster to other plants actually benefits the Aspen; and in many areas, particularly in harsh environments that are tough for other trees to survive, Aspen thrive and become climax communities, unique areas that serve as homes, food, micro-climates, and general habitat for multiple other species. Requiring open space with abundant sun and little competition, wildfires that can destroy all surface life pass over Aspen root systems, leaving the perfect environment for ramet growth and re-forestation.

All for One, and One for Fall!

All for One, and One for Fall!

Unfortunately, much of modern forest, range and livestock management – preventing wildfire; clearing out ‘unwanted’ plants in favor of what’s considered more desirable; removal of wolves and other predators, leading to historically dense populations of deer and elk which devour fresh Aspen stems; and assuming longer-living trees provide more favorable habitat (as well as more valuable lumber), is placing the iconic Aspen at risk. Even the long-lived Pando grove – one of the oldest plants in the world – is threatened by human construction and development.

Aspen colonies are the most widely distributed tree in North America, yet one often overlooked or even, for much of the year, unappreciated next to towering pines or broad oaks. Yet they are a species that is vital to a healthy, mature environment and the plants and animals that depend on the unique Aspen ecosystem.

If left alone and not overshadowed (literally), Aspen colonies will continue to thrive for thousands of years, creating homes for countless other species as well as providing some of the most glorious Autumn colors of any tree in the West. Which is quite a golden future.

http://www.nps.gov/brca/naturescience/quakingaspen.htm

http://cpluhna.nau.edu/Biota/aspen_forest.htm

^^^

Michonne Says: All the Gold-in-the-wind-trees are the same tree? But there must be one-hundred of them, how can they all be the same? And they are everywhere even near the moving water and the deep water and the rocks and everywhere. I think this story is something men made up because they don’t understand. Phooey.

Posted October 19, 2014 by ECOVIA eco-adventure® in SciSun

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