>>1457214They start at 7,000-8,000 ft at 31°N in AZ (Miller Peak has a small grove). The farther north you go the lower this level is in the west. It's just how Aspen grow out west, they grow in large groves, many of them are clonal colonies There is a clonal Aspen grove in southern UT that is 80,000 years old, a single individual cloned itself via roots and survived 80k years to the present. Some of these grove can be massive, especially ones in the PNW and the Rockies (especially the western Rockies in Colorado). There are also small groves on every mountain in AZ near or above 8,000 ft ASL.
