A five-stand chronosequence spanning >500 yr is used to characterize changes in age structure, overstory mortality, recruitment, and understory growth in developing Colorado Engelmann spruce (Picea engelmannii)-subalpine fir (Abies lasiocarpa) forests. Stand development follows a postdisturbance sequence of colonization, spruce exclusion, spruce reinitiation, and second-generation forest. This model of spruce-fir forest development reflects a range of disturbance intensities from large conflagrations to small-scale tree deaths. Catastrophic disturbance initiates stand development, and canopy gap replacements occur at predictable times during stand development as the life-spans of the two species are expressed. Previous, spruce-fir [...]