Making Sense of Mount St. HelensSTEVE NASH

Three decades out, the pulse of research quickens at a "hot spot:"

Seismographs never flatline. But thesix that monitor Mount St. Helens

(MSH) National Volcanic Monumentwere calm enough on 18May, register-ing only the routine burps and jittersof geosurveillance and a temporarilyplacid crater.

It was the 30th anniversary of theeruption, and if the geology was stilled,there was plenty of other activity. Doz-ens of cars wound their way upslopeto the Johnston Ridge visitor centerfor the occasion, carrying survivors,relatives of victims, aging Boy Scoutswhose camps disappeared in the blastzone, congressional staffers, and scien-tists, among others.

Kids jumped hard on the floor nextto the demonstration seismometer,joined at one point by a crew of tat-tooed bikers who moved the needlesmore emphatically. Everyone tried toglimpse the great St. Helens crater,almost too big for the picture windowsand shrouded much of the time underintractable fog.

For science, some features of themountain's ecosystem also remainoutsize and obscure, despite hundredsof studies and findings that have beencalled "paradigm shifting." About 50projects are currently active, in whatone administrator says is "a tremen-dous resurgence. One would have tocharacterize research at Mount St.Helens as vibrant."

The eruption in 1980 resulted in"a grand experiment that you couldnever have gotten anybody to fund,"

says Forest Service ecologist CharlesCrisafulli. "Everything's new. It's a newlandform." Unlike most misbehavingvolcanoes, this one provided an accessi-ble laboratory right along the Interstate5 corridor, with the research infrastruc-ture of major universities nearby.

Subsequent jockeying among pri-vate landowners, local business, timberinterests, government, environmental-ists, and scientists created the 43,300-hectare MSH national monument,administered by the US Forest Serviceand preserved for research and low-impact recreation.

Disturbance happensIn the restrained locution of ecology,what occurred in 1980 was a "distur-bance." It instantly recast the sereneFuji-form symmetry of the volcanoand its lush forests, meadows, andclear, snow-fed lakes into a stark deadgray blank slate, extending northwardaround a gaping, side-blown crater.

The eruption's first phase was thelargest avalanche in recorded his-tory, much of which quickly moved23 kilometers at speeds up to 70 metersper second to bury a wide area. Thiswas followed within seconds by a 250-degree Celsius stone-filled lateral blastcloud that quickly outpaced the ava-lanche, scouring, scorching, or topplingnearly everything over a 600-square-kilometer arc.

Over the ensuing nine hours thevertical component of the blastelevated a cubic kilometer of matterup to 27 kilometers into the sky, acolumn that rained ash over 11 states.Mudflows began almost immediately,hurling more than a hundred millioncubic meters of liquefied sand, gravel,rock, and earth entrained with cutlogs and other human-made debrisdown the North Fork Toutle RiverValley, some of it eventually reachingthe Columbia River, 120 kilometersdistant.

Pyroclastic material flowed for fivehours from the main vent, coveringmore than 15 square kilometers of thealready transformed landscape withsuperheated, incandescent volcanic

material up to 40 meters thick. Fifty-seven people were killed.

Among the first organisms visible afew days later on this still-active land-scape were scientists. They includedVirginia Dale, now of the Oak RidgeNational Laboratory. She had mountedthe defense of her doctoral thesis inmathematical ecology at the Universityof Washington the day the mountainstarted rumbling, and by the time iterupted a few weeks later, she andsome colleagues had a research pro-posal in hand.

"There was a lot of interest in howlife was going to return to the area:' shesays now. "A general sense was that lifehad been wiped out in the blast zone,so a big question was, what's goingto be the progression of life comingback?" The field of disturbance ecol-ogy gauges a wipeout's impact. Thecomeback is called "succession."

Chance features of the general chaoscan influence what develops afterwardin surprising ways, researchers discov-ered. Because this eruption happenedto occur in spring, snow still coveredsome of the mountain, providing amantle of protection for a few deeplyburied plants and animals that allowedthem to regenerate. The crater's slopesweren't paved with lava; they wereinstead blasted with loose volcanicmaterial, and in these deposits, seedscan sprout and buried plants emerge.

Dead or living remnants of the priorecosystem are "biological legacies,"suchas a stick, a root, some gophers left aliveunder earth and snow, a patch of soil,or a flattened forest. When a distur-bance of this size resets natural historyto something near zero, the legacies arethought by some to be more importantthan the disturbance itself in determin-ing what happens next.

Ecologist Jerry Franklin, now of theUniversity of Washington (UW) anda key organizer of the posteruptionresearch campaign, has said that he andother ecologists sometimes "got theirscientific butts kicked" in pursuing it."Backed up into a corner, we might havesaid yeah, I'm sure there are some thingsthat are still aliveout there, but the wholenotion that they were going to play the

major role in recovery was not some-thing that we were thinking about:'

"This is a totally unique resource,"Dale says. "There's no other site inthe world with this 30-year historywhere you've had hundreds of scien-tists learning the role of legacies, whichwe didn't understand before. That wasnot a concept that was even in the lit-erature before the eruption."

Nothing succeeds like successionMount St. Helens has helped reviseone of ecology's oldest preoccupations:trying to recapitulate the story of howcommunities of plants and animalsassemble themselves over time-howone suite of species succeeds another.The tabula rasa of the blast zone "cre-ated a great template to evaluate that,"Crisafulli says.

It's a given that life ultimatelyreappears if it is erased by disturbance."Nothing succeeds like succession:' asecologists say. But the stories in theirheads at the time were based on stud-ies of only a few disturbed ecosystems,especially abandoned farm fields in theeastern United States.

Logical rules had been laid outfrom these studies: Simple organ-isms arrive first, giving way to morecomplex ones. Certain species arepioneers, evolved to capitalize on earlypostdisturbance opportunities. Afterintermediate phases of competition, asuite of "climax species" such as long-lived trees arrives to establish a mostlystable, enduring scene.

At MSH, those succession scriptsbegan to fall apart. "It turns out, therewere lots of surprises:' UW commu-nity ecologist Roger del Moral says."The process is much less determin-istic than those diagrams in textbooksmight suggest."

Supposed late-successional speciesarrive early. Simple organisms likemosses show up late, or not at all. Cas-cade lupine and prairie lupine aren'texpected to occupy the same kindsof habitat, "yet there they are, oftenin the same square meter," del Moralsays, flowering in their thousands overbroad areas of the mountain. Unan-ticipated juxtapositions, arrivals, and

departures have characterized succes-sion on MSH.

Overall, del Moral's statistical analy-ses find that environmental factorssuch as soils, temperatures, moisture,and elevation don't predict much atall, especially in the early years aftera disturbance. Instead, chance domi-nates: which seeds might be blown orcarried in, what species are nearby ordistant, and the "biological legacy" fac-tors that survived the disturbance.

"We are now coming to believe thatjust because it happens in a particularway does not mean it must happen inthat particular way,"he says."There arealternative pathways that can get youfrom A to G by going through differentintermediate steps-say A to E to G orA to C to G- without going throughall the stages. Succession is not nearlyas deterministic as we thought."

If science aspires to the discoveryof general rules for how nature works,the posteruption research at MSH hasoften done more to catalog fascinatingparticularities-landing closer to nat-ural history at times and further fromtheory. Disturbance ecology and suc-cession studies have "struggled to findgenerality" and do not accurately inter-pret events at MSH, an overview of theresearch has concluded. "Properties of

succession are difficult to incorporateinto mechanistic models."

Dale says she feels no disappoint-ment about that, even after decades ofintensive research at a large-scale,well-protected site. "Ecological thoughthas been challenged, and people havedebated for a long time that we don'thave any grand unified theory of ecol-ogy as we do in physics, no periodictable as in chemistry," she says.

"I think that's the way it is, andI think ecologists need to recognizethis complexity. I'm working a lot witheconomists now. They are constantlygiving us their little supply-demandcurve, and we're saying that doesn'talways work. There are always excep-tions ....As a scientist, I keep seeing theexceptions, and MSH played that outbecause it was the chance events thatwere really important."

Franklin concurs: "Ecology is a sci-ence that lacks exceptionless empirical

laws and deterministic general theo-ries. Fundamentally, you need to knowthe natural history of the ecosystemand organisms to predict responses toa specific event such as an eruption.

"That is a great trauma to a lot ofbiologists and to a lot of ecologistswho work so hard to create theory, andthen almost inevitably the theory theycreate has to do with special cases. It'snot general theory at all."

Postcatastrophe prescriptionsTheory aside, researchers say MSHand its research programs have taughtcrucial lessons for how, and how not,to manage big disturbed landscapes.These are not in short supply. The an-niversary at the volcano also markedthe fourth week of another cata-strophic eruption, which was addinga roughly estimated 9.5 million litersof oil to the Gulf of Mexico ecosystemeach day.

Mount St. Helens research is nowa source of data for those who mustcope with the aftermath of both natu-ral and human-caused disturbances,Crisafulli says."Early on we were ridi-culed. People said, it's part of a stampcollection, it has no value or relevanceto other places, but indeed it does."

Three hundred miles to the southof MSH, in southern Oregon, researchdata became part of an acrimoniousdebate over whether to salvage-logsome of the 200,000 charred hectaresof the Siskiyou National Forest in thewake of a 2002wildfire, the state's larg-est and costliest in at least a century.Crisafulli was consulted by a Texascompany doing reclamation work onWestern strip mines, including a prob-lematic site inWashington. His analysisof its climate, soil data, and availablenutrients suggested that native lu-pines would be good to consider forland cover. The US Geological Survey

contacted him to ask how a formerlyinundated landscape might evolvewhen an old dam was removed fromthe Elwha River near Washington'sOlympic National Park.

"We do know enough to make sen-sible suggestions for management,"says Dale, the lead author of a researchpaper titled "Ecosystem Managementin the Context of Large, InfrequentDisturbances." One of its more salientprescriptions: The more legacy lefton the landscape, the more rapidly adiversity of life forms returns. Anotherlesson:Messiness is good. "We'velearnedthat you don't necessarily need to cleanthings up" after catastrophic change,Dale says.

For example, despite strong op-position from many ecologists, state,federal, and private foresters removedmillions of board feet of dead logs thatwere part of the "biological legacy" ofthe eruption at MSH. The timber wastaken out for its economic value andalso, proponents argued, to forestallwildfires and a potential explosion oftree beetle populations. Subsequentresearch at unsalvaged areas of MSHfound that these fears were not real-ized. Salvaged areas have recoveredmore slowly, with comparativelyimpoverished biological diversity.

Just after the eruption, a contro-versial and expensive aerial reseedingprogram sowed exotic grasses on steepslopes. Sheet erosion quickly washedaway many of the seeds. The attemptwas made in the wrong season, too, sogermination was minimal. Clouds ofthe seeds sometimes drifted elsewheredownslope, however, causing mousepopulations to explode. When thisfood supply was exhausted, the hungrymice gnawed tree bark, suppressingforest recovery and diversity, studiesfound.

Snags and debris were cleared fromslopes and streams-another instruc-tive error, as things turned out. "Manytimes when we have these large distur-bances money is spent because that'swhat we know how to do," Dale says."We don't always spend it in a verywise fashion. We often spend it toclean up things. Nature's not clean.

"Leaving a big jumbled-up mess ledto quicker recovery because pocketsof vegetation could get started, seedscould get established, it was wetter,"she says. "That messiness is a part ofnature." Research on cleanup effortsfollowing hurricanes has led to thesame conclusion, she adds.

Data from MSH have also pro-foundly affected the national debateover clear-cut timber harvesting,Franklin says. As one of the architectsof the Clinton-era "spotted owl" set-tlement, the Northwest Forest Plan,he brought volcano-generated experi-ence to the negotiations. "It gave us thewhole notion that instead of trying tototally sweep clean, as we do with clearcutting, if we're interested in thingslike biological diversity and other kindsof ecosystem processes besides timberproduction, maybe we'd better rethinkour concepts:"

Replanting privately held forestacreage at MSH has mostly yieldedstands of trees for wood production."It comes at an ecological cost," Crisa-fulli says. "We're seeing that at St. Hel-ens when we look at mammal diversityand herb diversity."

Hot spots for researchNear the end of a hypercaffeinated PBSdocumentary that aired the week beforethe anniversary of the eruption, viewerswere assured that "today, the slopes ofthe mountain are a living testimony tothe miraculous ability of nature to re-turn from the dead." Symphonic brassesswelled under the libretto.

Although miraculous returns fromthe dead do not appear in the research

literature, scientists have indeedseemed awestruck by the exuberantand ingenious reestablishment of wil-lows, microbes, elk, balloon spiders,rock wrens, horned larks, salmon,trout, and thousands of other spe-cies.

Franklin, a career-long devotee ofold-growth forests, is delighted bythe productivity of this infant land-scape. "It has finally forced us to lookcandidly at this period between anintense disturbance and when theforest canopy again closes, and treesresume dominance over the site. Youhave ecosystems that are characterizedby a diversity of plant life forms: herbs,shrubs, and trees are scattered throughthat. Reptiles, amphibians, mammals,birds, and of course larger ungulates,like elk, and their predators are allfavored by that condition."

The reassembly of the former old-growth evergreen forest ecosystemcould take hundreds of years. It may notrecur at all. Wild cards such as exoticinvasive species or more eruptions maygenerate a different outcome. Globalwarming might bring a more open,pine-dominated forest instead. "In thistime, unfortunately, you can't be sure,"Franklin says. "Any time you put anecosystem through a wringer like that,it may not come back."

"What will their presence do here?"he asks.

Mount St. Helens can be viewedas an analog to global warming-another possibility for future re-search. The eruption's replacement ofa damp, cool, fir forest with a muchdrier, warmer, and windier environ-ment may prefigure similar changesin other areas as the global climateshifts.

Another natural process is alsounder way as the years pass. "A gen-eration of scientists who cut their teethhere are moving close to retirementnow, so we need to bring on the nextcohort;" Swanson says. Part of thatrecruitment effort pulls interdisciplin-ary teams of scientists and others toMSH every few years, including thisone. Veterans and younger research-ers camp, work together, mind theirresearch plots, generate new ideasabout what to study, then "test themwith one another around the campfireand some beer in the evening;" he says.The process, begun by Franklin a gen-eration ago, addresses another of hisconcerns: that ecologists, and others,not be "blind-sided by their own pre-conceived notions."

Franklin saw plenty of rottinglogs during his first years in forestryresearch, never guessing their ecologicalsignificance as providers of shade, mois-ture, soil nutrients, and shelter. Theirimportance became apparent at MSH."If you can overlook something as bigand common as that, then we're still notseeing everything. What big log is lyingout there on the forest floor that I'm notseeing now? I'm still having revelations,and I've been at this for 50 years."

30 years. There are no other exam-ples.... Think they'd buy that?"

learning to see the next big logThe tumult of constant change ona. young landscape sets the researchagenda for the next decades. Morecomplex food webs are developing.Living things, rather than rocks, aircurrents, minerals, or moisture, arebeginning to dictate the direction ofsuccession, researchers say.

As plants multiply, so do the ranksof plant -eaters such as elk and insects."It's generally thought that it's plantsduking it out for resources, nutrients,light, space;" Crisafulli says. Herbivoresare now exerting enormous influencetoo, he says. The transformation fromherbaceous to woody vegetation willcatapult further change toward moreshade-tolerant plants and the smallmammals and birds that are adapted tolife in trees.

Wolves,whose reintroduction power-fully altered the Yellowstone ecosystem,are likely to move into this landscapein the next decade or so, Forest Serviceresearcher Frederick Swanson predicts.

Meanwhile, exotics seem to be play-ing a surprisingly modest role so far,Crisafulli says, and MSH has becomea biological hot spot for the wholeCascade range, from California to Brit-ish Columbia. There is no equivalentarea in the Cascades with the numberor the diversity of bird species, forexample. And there is far more bio-logical diversity at MSH today thanbefore the eruption.

All the same, some near neighborshave decidedly mixed feelings about thescience enterprise at MSH. Maintainingit as a research laboratory for the obser-vation of natural forces has meant keep-ing human influences at bay, at least tosome extent. Off-trail hiking, off-roadvehicles, hunting, fishing, horses, dogs,and camping are banned or restrictedin some sections. Proponents of moretourism have advocated easing thoserestrictions and building a new highwayto link the eastern and western sides ofthe monument.

The area's congressional delegationconvened a task force of local electedofficials and stakeholders to investigatethe issue, and its report was formallypresented in the weeks before theanniversary. The report recommendedforming a committee "to vet recre-ational opportunities while main-taining a scientific conscience." But itconcluded that more recreationalaccess of all kinds is of "paramountimportance to the public;" and in pur-suing more of that, the current ForestService administration was considereda better bet. A proposed conversionof the monument to a national park,under the supervision of the NationalPark Service, was rejected.

"I can see where they're comingfrom," Dale says. "Land is locked up,and people always want access to land."But the region is already rich in envi-ronmentally compromised areas thatcan be used for recreation, she adds."Large research land is rare, especiallywhere we know what's happened for