Dr. Joanne Stolen
Special to the Daily

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July 23, 2011
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Summit Outside: Aspen: the world's largest organism

Aspen trees are one of the hallmarks of Colorado. Not only is a famous ski area and town named after the tree, but they are depicted in most of the beautiful fall pictures of the Rocky Mountains. The unique-shaped leaves are dipped in gold and silver and made into jewelry and sold in local gift and jewelry shops.

One popular trivia question is: What is the largest organism in the world ? It is the Aspen!

Aspen typically grow in large colonies which are clones derived from a single seedling, and spread by root suckers. New stems in the colony can appear 130 feet from the parent tree.

An individual tree can live for 40-150 years above ground, but the root system of the colony is long-lived and can be thousands of years old.

They send up new trunks as the older trunks die off above ground. A colony in Utah is thought to be 80,000 years old.

Some aspen colonies become very extensive, spreading about 3 feet a year, eventually covering many acres.

Aerial surveys of Colorado completed in 2006 show that almost 60 percent of aspen forests in Colorado, mostly the mature trees, died between 2003 and 2006.

Lower-elevation forests generally have higher mortality than upper-elevation forests. In many cases, trees younger than about 50 years have survived.

The severe droughts of those past years may have played a role in the widespread death of aspen trees.

A wide variety of insects and diseases occur in aspen forests as well. Fungal diseases and stem borer insects are more common as trees become more stressed.

Forest tent caterpillars eat aspen leaves, and periodic outbreaks may defoliate entire aspen canopies in early summer.

Many of the aspen forests in Colorado developed after a stand replacing disturbance such as fire. The root systems of aspens usually survive fires, since they are well below ground and after a fire they send up thousands of new stems to regenerate the forest.

Aspen do not thrive very well in the shade, and it is difficult for aspen seedlings to grow in an already mature aspen stand. Fire allows the saplings to flourish in open sunlight in the burned landscape.

The future of forests with dying old trees will depend on a well-developed, sapling- size, aspen trees, however, a large portion of Colorado's aspen landscapes experience very heavy browsing by elk, deer and livestock.

Young aspen bark provides seasonal food for the hare and other animals in early spring and aspen is also a tree of choice for the beaver.

Browsing of aspen suckers may be a major problem because of high animal populations, and the small proportion of landscapes burned in recent decades.

In many cases, conifers such as lodgepole pine and Engelmann spruce establish as seedlings soon after the same fires, but the faster growth of aspen suckers allows aspen to dominate the forest for decades. The continued growth of understory conifers however, reduces the opportunities for new aspen suckers to develop, and conifers may replace aspen as the old aspen trees eventually die.

Not all aspen forests have conifer seedlings and saplings to contend with however, and these forests may remain dominated by aspen.

Aspen are popular in forestry, mostly because of their fast growth rate and ability to regenerate from sprouts, making the reforestation after harvesting much cheaper, since no planting or sowing is required.

Aspen wood is white and soft, and ideal for making matches, because its low flammability makes it safer to use than most other woods.

Shredded aspen wood is used for packing and stuffing, sometimes called wood wool.

It is often used for animal bedding, since it lacks the chemicals contained in pine, which are thought to cause respiratory system ailments in some animals.

Heat-treated aspen is used for the interiors of saunas.

Although standing trees sometimes rot from the interior outward, the dry aspen timber weathers very well, becoming silvery-gray and resistant to rotting and warping, and has traditionally been used for construction.

In the 1800s scientists extracted and identified salicin as the potent pain killing medicine found in the bark of aspen. Pharmaceuticals then went on to develop and market a synthetic version called acetylsalicylic acid which we know as Aspirin . The pain killer is in the inner bark of the tree known as the cambium layer. If you need a pain killer in the woods, you can take a knife and scrape off the outer bark and then the inner bark and chew on the inner bark. You can also boil the inner bark and make a pain-killing tea: two teaspoons in a cup of water boiled for 10 minutes.

Leaves and leaf buds of aspen have been used by native peoples to treat burns, irritations, aches and swollen joints.

A bitter herbal tea from bark and leaves has been used to treat mild urinary tract inflammations.

The Ojibwe Indian tribe used the inner bark of the trunk as a poultice for wounds.

The aspen tree has was often planted near the dwellings as it was reputed in many countries to drive off evil spirits,

According to an Eastern Slavic legend, Judas Iscariot hanged himself on an aspen tree, hence its leaves have been trembling with horror ever since.

An aspen stake was believed to be one of the weapons suitable to kill a vampire or a werewolf and a bigger stake could be driven into the grave of a person condemned to damnation, so as to prevent them from rising from the dead.

Legends and superstitions aside, the aspen is an amazing tree!

Breckenridge resident Dr. Joanne Stolen is retired from teaching microbiology at Rutgers University. Some of the block prints of the animals she writes about can be seen locally. During the summer she coaches rowing at Frisco Rowing Center.


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The Summit Daily Updated Jul 23, 2011 05:42PM Published Jul 23, 2011 05:40PM Copyright 2011 The Summit Daily. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.