The canopy and understory vegetation of 19 aspen (Populus tremuloides) stands near Crested Butte, Colorado, were characterized in 1964 and were resampled in 1994 to assess the successional status of aspen communities. After 30 yr, aspen basal area was unchanged although the total number of trees decreased by 23%. There were 42% more aspen over 18 cm dbh. Understory species remained relatively unchanged; Thalictrum fendleri, Lathyrus leucanthus, Carex geyeri and Ligusticum porteri, the four most dominant species, as measured by cover, in 1964 were also abundant in 1994. Conifer basal area and the total number of trees remained constant over 30 yr, though the number of stands with conifers increased from six to 10. These results suggest that the aspen communities in the Crested Butte area are persistent, and while Picea engelmannii and Abies lasiocarpa may gradually replace some aspen stands, particularly on N-facing slopes, this replacement may take centuries.