25 weeks or 25 years?
25 weeks or less.
The single greatest surprise to scientists entering the blast zone shortly after the eruption was the realization that many organisms survived in, what initially appeared to be, a lifeless landscape. Scientists entering the blast zone for the first time found a mostly gray and brown landscape covered with dead trees and a uniform covering of ash and pumice.
It wasn’t long before scientists working in the area found surviving populations of plants and animals. This was particularly evident in areas protected by snow cover and where erosion had thinned the overlying ash deposits (along streams and in gullies that formed on hillslopes). Plants were observed sprouting from the pre-eruption soil surface and signs of activity by gophers and ants indicated that subterranean animals (living below ground) had survived beneath the volcanic ash.
The survival of plants and animals in the midst of the apparent total devastation was of special interest to the scientific community. Early studies have demonstrated that, even after a large-scale, catastrophic disturbance, recovery processes are strongly influenced by carry over of living and dead organic material from pre-disturbance ecosystems. At Mount St. Helens, ecosystem recovery was influenced not only by the survival of plants and animals, but also by the tremendous quantities of organic material that remained in the standing dead and blown down forest.