The greatest damage that was caused by the Mt St Helens eruption May of 1980was the suffocation of the land by huge amounts of volcanic ash that is somewhat sterile and can be toxic or caustic depending on the chemical components of the ash. But it is important to remember that one of the most fertile and famous wine growing regions in the world, the Napa Sonoma Mendicino region, is special because ash from a monstrous volcanic episode is a component of the soil!
One exciting revelation from the return of life to Mt St Helens is that, where plant life can return, it is not returning in the expected fashion: beginning with mosses, then grasses, shrubs and trees. These life forms are returning simultaneously! Previous expectations were based on observing only abandoned fields or formerly glacial terrain.
In other words, all of the major elements of reforestation are returning at the same time, where the soil is of a quality that allows plant growth.
Insects and animals of all types are reestablishing colonies and habitat, affecting plant growth to create new and unique habitats that are based on their activity. Fireweed seeds have wings and blow along the wind currents. There is established fireweed that grows, flowers, reproduces, then dies to mix with the volcanic ash to create new and improved soil from the masses of organic material.
The massive number of downed trees have attracted birds, such as the Mountain Bluebird and the insects that feed on decaying plant material to create whole new habitats that are being adapted and changed through the actions of the insects and other life.
The larger mammals, such as Elk and Deer are migrating from one place to another, mixing the volcanic ash into the soil to create increasing areas where vegetation can grow. Their droppings produce valuable fertilizer for the vegetation and they carry plant seeds in their fur and on their hooves.
Lupine was the first and most aggressive plant to reestablish at Mt St Helens. Lupine fixes nitrogen, which makes it a soil conditioner as well as vegetation. But a caterpillar of the Filatima sp. moths is an herbivore that is threatening the Lupine, which illustrates the challenges that life faces in attempting to reestablish in a completely denuded area. These herbivores are having a huge destructive impact on the Lupine as the best hope for reconditioning the soil to allow the establishment of other species of plants.
But even the tiniest of burrowing mammals are making headway! The Northern Pocket Gopher has been busy digging under snow and ash to get to food and habitat, creating areas where soil is conditioned to allow for more vegetation growth.
As a result, Mt St Helens and the slow recovery from one of the more spectacular volcanic devastations in our times is serving as a brilliant laboratory for studying the process of restoration in huge areas.
A 1998 USGS Report
A Stunning NASA Video Presentation of the Recovery
Science Daily, “Mt St Helens Recovery Slowed By A Caterpillar”, 16 Nov 2005
