What is status of plant recovery at the volcano 20 years later?
The first twenty years of vegetation recovery at Mount St. Helens can be viewed as the opening chapter in a long-term (200 to 500 year) successional sequence that will eventually lead from open, ash-covered blast zone to old-growth forest. During the first five years the recovery process was dominated by surviving plants that resprouted from blast zone hillslopes where pre-eruption soil was covered with ash and pumice. On steep slopes the recovery process was helped by erosion that removed the overlying ash releasing the roots of buried plants in pre-eruption soil. Plant survivors that spread rapidly through vegetative reproduction accelerated the overall recovery process. Colonizing species that established from wind blown seeds soon joined surviving plants. Many of these seeds took root in the leaf-mulch and shade provided by established plants. Since 1990 there has been a steady progression in the number and overall variety of plants in the blast zone. This is the result of a “filli
