The 1980 eruption of Mount St. Helens created extensive devastated landscape that are undergoing varying degrees of recovery. This has provided ecologists with a unique opportunity to study plant colonization of pristine landscapes. The post- eruption landscape had various modes of disturbance, ranging from tephra to mudflows to incandescent pumice. Rate and direction of plant recovery have been similarly heterogeneous. This research proposes to continue long-term studies of the heterogeneous recovery process of vegetation. There will be three components (i) monitoring of permanent plots and permanent grids for seed fall, nutrients and substrate moisture; (ii) performing experimental habitat alterations and density manipulations of pioneer plant species; and (iii) modeling to build a conceptual framework for determining probabilities species establishment. By examining the recovery process in a variety of environments, using common methods of data collectionand analysis, a comprehensive picture will be constructed of primary succession on Mount St. Helens in particular, and of primary succession, in general,
