This is scientific American 62nd Science. I'm Annie Sneed.

It lives in South Central Utah and it's huge.

In fact, it is thought to be the largest living thing on the planet.

It's a stand of trees.

A field of aspens, all clones, and all connected at the roots.

Called Pando, the Grove was first characterized by scientists in the 1970s, and it's probably

existed for many thousands of years.

But now a study finds that this massive ancient organism is failing.

More than 80% of the entire pando clone is in a non-sustainable state that has the potential to collapse and significantly reduce the size of

this world's largest organism in the next 10 to 20 years.

Paul Rogers, Director of the Western Aspen Alliance at Utah State University.

The cause of this crisis?

Erbovores, mostly deer.

Parts of Pando are fenced off, but even those areas are still under attack.

Young aspen trees are so nutritious that animals really want to get to them,

particularly late in the year when the rest of the forest plants are senest and dried up.

I think that there's perhaps some very healthy ones are able to jump over the eight foot fence.

The deer's aggressive browsing of young Aspen poses a huge threat to Pando.

We see a big gap in the demography, and I often use the human analogy that this is a forest that is almost completely composed of senior citizens and we have no

mature healthy individuals, we have no middle age, we have no teenagers, we have no babies, and that's a really

dangerous situation for Aspen because it really depends on continuous growth of the whole

clone, you know, so you should have a really diverse

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