ABSTRACT
Environmental conditions, such as levels of nutrients and moisture, and levels of live and dead organic materials carried over from the preemption ecosystem varied widely. Mount St. Helens will continue to provide an important laboratory for studying natural processes of ecosystem recovery. The 1980 eruptions of Mount St. Helens comprised a complex of events with multiple and varied impacts on the surrounding mosaic of ecosystems. Spirit Lake, located northeast of the mountain, was the result of damming of the upper Toutle River drainage during earlier eruptions. Forest vegetation covered the lower slopes of the mountain as well as most of the surrounding landscape. Subsequent eruptions of Mount St. Helens have generally been small, dome-growth events, with minor impacts outside of the crater area. The primary volcanic disturbances of the landscapes surrounding Mount St. Helens dramatically altered hillslope hydrology and sediment availability.
