The Sangre De Cristo mountain range runs from Santa Fe, New Mexico up to the Arkansas River Valley in Colorado. One of its features is the world’s tallest Aspen trees – located in huge groves near the Santa Fe Ski Basin. I used to work as a wilderness ranger in those mountains.
http://www.flickr.com/photos/mhill110/1516037701/
The Aspen groves are the result of massive forest fires which occurred during the 1890s. This was one of them.
Nature determined the best plants for that region and needed to remove those that grew under different climate conditions. This effect is seen in many geological records.