A long-term study of recovery and primary plant succession in higher elevations was initiated in 1980. The objectives included to document recovery and invasion in several distinct habitats (e.g. lahars, pumice, blasted ridges, tephra) and to determine the mechanisms of invasion and establishment. In addition, large grids of contiguous 100 m2 quadrats have been established since 1986 in several habitats.
Recovery patterns vary with the size and intensity of the initial impacts. Tephra impacted sites were completely recovered by 1983 and subsequent vegetation change has not been directional. In contrast, intensively impacted sites have recovered much more slowly. Recovery rates differ primarily with the degree of isolation, but the intensity of the impact also governs the recovery rate. For example, lahars surrounded by intact vegetation have acquired as many species as intact vegetation, but community structure remains very different. Total cover after 11 growing seasons remains less than 10% of intact vegetation. Nutrients limit the development of biomass and cover, but most species in the immediate vicinity have established on lahars.