Wild Lands of the West | The BLM, National Geographic Magazine: Aspens Begin Their Show

Green trees in various stages of turning yello on steep mountainside.

Aspens gild the slopes of the San Juan Mountains in Colorado on an early autumn morning in Bureau of Land Management terrain that includes 14,000-foot peaks.

Aspens are native to cold regions with cool summers and grow in large clonal colonies, derived from a single seeding and spreading by root suckers. Individual trees can live for 40–150 years, but a root system can survive thousands of years, sending up new sprouts as older trees die off.

Public lands are in the perfect environment for aspens to spread, however, in the urban landscape they are short-lived trees that are affected by numerous insects and diseases.