The trees that make up the colony are clones: they are genetically identical. The colony is made of about 47.0000 single trees and covers about 47 hectares (120 acres). The roots of these trees are linked. A single aspen tree will not grow older than 100 to 130 years. New trees will grow, others will die off. The whole organism may be about 80,000 years old. It is the oldest known living organism on Earth.
Humans brought mule deer into the region, which may be a threat to Pando. On the other hand, aspens are resistant to browsing: their leaves contain some unpleasant chemicals. In a study done in the 2000s, scientists analyzed aerial photographs of the region. They found that Pando has not grown in size in the last 30-40 years. Therefore they say that it may be threatened.