National Geographic : 2010 May
. state as possible, allowing primarily natural geo- logic forces and ecological succession to con- tinue unimpeded." Mostly closed to the public, this part of the blast zone has become one of our planet's grandest experiments. e volcano came back to life from 2004 to 2008, shooting o plumes of steam and ash up to 30,000 feet into the sky, growing a new lava dome in its crater, and captivating sightseers and geologists. But many of the area's greatest insights have come in the eld of ecology. As a natural lab to study the rebirth of ecosys- tems, the blast zone has no equal. "It's the most thoroughly studied large-forest disturbance in the world," says Crisafulli, examined from nearly every angle, at nearly every scale, from molecules to ecosystems, bacteria to mam- mals, steaming geothermal vents to waterlogged meadows. Almost daily, callers inquire about the lessons of St. Helens. One woman is interested in salamanders, another in toads. O cials in Alaska and Chile want to know what to expect a er eruptions of their own. A key lesson is the importance of "biologi- cal legacies"---fallen trees, buried roots, seeds, gophers, amphibians---that survived the blast, thanks to snow cover, topography, or luck. Ecologists had assumed rebirth would hap- pen from the outside in, as species from border areas encroached on the blast zone. But recov- ery has also come from within. Starting with a single plant Crisafulli discovered in 1981 on the barren, 3,750-acre expanse known as the Pumice Plain, purple prairie lupines Why show St. Helens with its summit intact? Ramona Kmetz Lauzon, who painted the mural in Castle Rock, Washington, in 1996, explains, "People said they'd rather see the old mountain."