Mountain much studied

When Mount St Helens erupted nearly 30 years ago,it flattened more than 150 square miles of forest,sent millions of tonnes of mud and debris...

When Mount St Helens erupted nearly 30 years ago,it flattened more than 150 square miles of forest,sent millions of tonnes of mud and debris,filled the sky with ash and left at least 57 people dead.

In the process,it also created an unusual outdoor laboratory where researchers have worked ever since to answer an increasingly urgent question: How do landscapes recover after violent disturbance?

It has long been one of the most fundamental questions in ecology, said Charles M. Crisafulli,an ecologist at the Pacific Northwest Research Station,an agency of the US Forest Service,which manages the mountain. And if,as seems likely,a warming world brings more storms,fires,droughts and floods,the research on the mountain will only grow in importance. Mount St Helens allows us to evaluate things we could not evaluate anywhere else, Crisafulli said.

But now the work is caught up in a debate over management of the mountain,designated after the eruption as the Mount St Helens National Volcanic Monument. Some say the 110,000-acre monument should be a national park. Some say the Forest Service should manage it differently. There is a certain segment of the population who would say,Its been 30 years,and its over, said Peter Frenzen,monument scientist with the Forest Service. Over the years,so many researchers have spent so much time on the mountain that some call it the most-studied landscape on Earth. But if much has been learned there,much remains unknown,and the process is playing out slowly,Crisafulli and Frenzen said one day recently as they hiked into the zone.

A few miles away,in land managed by Weyerhaeuser,a timber producer,thick stands of trees laboriously planted by hand immediately after the eruption rise 70 feet tall. But the zone is largely treeless,studded with house-size rocky chunks,called hummocks,that broke off the top of the mountain when it exploded. A few scrubby trees,like red alder,have re-established themselves,and ants,frogs,meadowlarks,beavers and other species have moved in. Still,Frenzen said,The plant ecology and the forest ecology are only beginning. We have only seen the opening chapter.