Scientists take on the ecosystem.

On a sunny September afternoon a group of bureaucrats sits cross-legged in the meager shade of an east-side ponderosa pine. One speaks passionately of soil, another of fire, yet another of insects. Their give and take is as heated as the California sun blazing down between brittle green needles. The dialogue could affect national forest management from Canada to Baja.

For the first time in its 89-year history, the USDA Forest Service is studying what really goes on in the western woods. Its laboratory is Blacks Mountain Experimental Forest, a 10,000-acre tract on Lassen National Forest in California 300 miles northeast of San Francisco. The dozen debating bureaucrats are Forest Service scientists whose expertise runs the gamut from brown creepers and bark beetles to carbon budgets, fire history, arid the reproductive cycles of the golden mantled ground squirrel. They have assembled at Blacks Mountain for a unique study, broad-based in scope and bold for an agency often criticized for its preoccupation with growing bigger and better boards.

"We have data that tells us lots and lots about trees, but it doesn't tell us anything about the ecosystem," says team leader Kathleen Harcksen, a Forest Service forester. "If we're going to provide forests into the future and not just lock everything up, we've got to understand how forest systems interrelate."

At Blacks Mountain the interdisciplinary team of scientists has launched a series of forest experiments designed to respond to questions being asked by an increasingly demanding public - the big questions about biodiversity, ecosystem management, and the long-term future of the nation's natural resources. For answers, the scientists are looking to pine snags, hairy woodpeckers, wood rats, soil fungi - everything that plays a role in what lives and dies and recycles back into the forest.

At their disposal are 2,500 acres of regal old-growth trees whose majestic crowns tower over a pristine, park-like forest floor. The Forest Service researchers also have access to around 100 acres of commercial clearcut where a scattering of spindly pines is slowly establishing a new forest. Between these extremes are over 6,000 acres where their predecessors experimented with insect salvage harvests, commercial thinning and logging that removed 85 percent of the merchantable timber.

And they have data - box upon cardboard box of data delivered to the scientists' Redding, California, office from the federal archives. Blacks Mountain is one of the few forests in the United States with more than 50 years of records on forest structure, says Phil Aune, silvicultural lab program manager. Designated in 1934 as an investigative site for the Pacific Southwest Research Station, it was the focus of experiments conducted by the Forest Service as early as 1910. Those experiments detail various silvicultural methods and the best available techniques for harvesting and hauling timber. The data is limited by the questions that were asked, Aune says. "The emphasis then was absolutely on the growth and development of the forest."

But it is the existence of any forest data at all that attracted many of the current band of scientists to Blacks Mountain, says Phil Weatherspoon, a Forest Service fire ecologist. The team's study of decaying logs, for example, relies on tree measurements taken at five-year intervals since the 1930s. "We have an absolutely unique opportunity because of those records. They let us relate the decomposition stage to how long the tree has been on the ground. There are very few places where we could do that."

For most of the scientists, working together is as unique as working with a half-century of data. Cooperation does not come naturally to researchers accustomed to answering their own professional questions in self-defined isolation. "It was a tug," says George Ferrell, a Forest Service research entomologist. "Different disciplines are not always in agreement over things like slash and forest openings. We all had to give a lot."

They began their teamwork in 1991 with a Herculean labor: three days together in a room without windows. Suspicious, competitive, testing their dominance, Harcksen says she wondered at first if they would all survive. "Scientists aren't used to making compromises. Those first three days were a real test of character."

Emerging unscathed and enlightened, the scientists devoted the next 18 months to further discussion before generating a formal plan to guide them and their successors. The seven-page single-spaced prospectus outlines a 50-year study that evaluates everything from genetic diversity to dirt. "We know what happens when we clear-cut. What we don't know is what happens in old-growth stands or what happens as these stands change," says William Laudenslayer Jr., a research wildlife biologist with the Blacks Mountain forest.

To find out, the scientists have divided 3,000 acres of the experimental forest into 12 250-acre study plots laid out on a 100-meter grid marked by small metal monuments. Here they will create two forest structures, one an old-growth type with trees of various species and heights, the other a more simple, even-aged type of forest. Plots of each type will then be grazed by cattle and treated with prescribed fire. Separate plots of each forest type will not be grazed or burned. To maintain a control, the scientists have also identified five 100-acre research natural areas where they will conduct no timber harvests, prescribed burns, or grazing. They have spread their individual experiments across all the various forest plots.

In a dense thicket of young pines, Forest Service soils specialist Robert F. Power plunges his hand deep inside the soft pulp of a rotting log. He draws some out, squeezing water into the dry late-summer duff. Powers is searching for information about the ecosystem under the forest litter that layers the ground. Every three months he retrieves specimens from three-inch plastic pipes he has buried around the Blacks Mountain forest. "If the ground cover is important to the health of sustained production, how much should we leave? And how much timber should we harvest?" says Powers. The nitrogen content of these soil samples will help Powers determine the effect of decomposing plants, duff, and other forest litter on the quality and quantity of timber a site can produce.

Weatherspoon is also looking for information in the soil, but his tools are thermometers. As a fire ecologist, he wants to determine how often and with what impact fires raced through the east-side ponderosa pine stands before the Forest Service began controlling fire in the 1930s. But he is also interested in answering shorter-term questions about the timing of prescribed fires. Most intentional forest burns have been conducted on the basis of fee safety and air quality regulations, not forest health.

At Blacks Mountain, Weatherspoon has embedded dozens of thermocouples under the thick bark of ponderosa pines and next to their roots several inches below ground level. He ignites the forest litter at various times under various conditions, always taking careful temperature readings. The results, he says, could change the intensity and the timing of future prescribed forest burns around the West.

Like it or not, working together and sharing the Blacks Mountain laboratory has stimulated each of the scientists to ask questions they might not have considered on their own. "Nobody knew much and what we did know we didn't tell," says Bart Cord, a member of the wildlife biology team. He is clinging to a wriggling golden mantled ground squirrel he just removed from a Sherman live trap. The data Cord collects will help determine how small mammals affect forest health in general and timber regeneration in particular.

Already he has learned that many ground squirrels have two litters a season. "Why? How do I know? Do they say, 'Hey, Mama, it's a good cone crop. Let's have another litter'? That's part of the interest of the game. We're all finding out new things and doing what we haven't done in the past."

Ferrell, a career research entomologist, admits he is much more interested in decaying logs after several years of collaboration with Powers and others. Ferrell's focus is on snags and their use by everything from squirrels and Modoc white-headed woodpeckers to Phellinus pini, a heart-rot fungi. Peeking inside a funnel-shaped insect trap suspended from a branch 30 feet up a dying ponderosa pine, Ferrell studies the week's catch. Earlier in the summer he stapled packets of commercial pheromones to 24 large Blacks Mountain pines to attract bark beetles and kill the tree. He girdled another 24 trees to determine which kind of death makes the most useful material for the forest ecosystem.

Like the other experiments, Ferrell's studies are designed to measure both long- and short-term effects. For an agency historically disposed to crisis management and this year's political fancies, the Blacks Mountain research is an anomaly. "We're studying the process from an ecosystem standpoint to see the whole picture of how the woody bit-mass of the forest is returned to soil," says Ferrell. "Our goal is to achieve forest conditions we can sustain for 100 years."

Beyond the value of the answers for their own scientific worth, the questions being asked at Blacks Mountain are important as a signal of change within the Forest Service. It was here in 1937 that Duncan Dunning, author of the site and crown classification systems used by foresters throughout the West, developed a plan for sustained-yield forestry as an alternative to what he called "lumbering," then widely practiced on public and private lands. But Dunning soon found himself out of step with the agency, which was already beginning its push to increase yields and decrease harvest cycles. "National priorities shifted. The emphasis was on timber then," says Weatherspoon.

So strong was that emphasis in 1972 that the Lassen Forest exploited the Blacks Mountain experimental stands to achieve its 20-million-board-foot "super-sell" quota meted out by President Nixon. Worse yet, in the rush to get the spoils to market, Lassen foresters, ignorant of the Dunning tree class system, kept only speculative inventory records. The harvest that allowed then-Lassen Forest Supervisor Jim Berlin to produce his mandated volume obliterated 35 years of data with a single, knee-jerk response to timber industry politics. Donald T. Gordon records the results with a terse entry in his 1982 history of Blacks Mountain: "Total loss."

But in the early 1990s, as public outcry and lawsuits over forest clearcutting proliferated, national priorities shifted again. The new emphasis on ecosystem health and long-term forest productivity has funneled $261,000 a year plus salaries to Blacks Mountain.

For Ferrell, the Blacks Mountain research offers a welcome break from what he calls "Nazi forestry." "Most of us spent years trying to produce the blond-haired blue-eyed superior race of trees. Things have opened up a lot. Now I have almost a frightening amount of freedom." Instead of limiting himself to the insects attacking California red and white firs, Ferrell is working with the entire regime of insects and fungi that invade a tree as it dies and becomes a snag. Already he suspects that death by natural causes - insect invasion - benefits a wider variety of animals than girdling.

While each of the scientists has encountered predictable failures in their experiments, the biggest threat looming over the entire Blacks Mountain project lies thousands of miles beyond the forest and the creatures who inhabit it. Ultimate control over whether the scientists will see their experiments through 50 years - even another two years - rests with politicians in Washington, DC.

"Congress doesn't think in terms of long-term investments," says Weatherspoon. "It's an irony not lost on those of us involved in forest research." Although Congress slashed 1996 funding for Forest Service research by $26 million nationwide, the Blacks Mountain project retained its direct budget at the 1995 level. But the research will not expand, an indirect effect of the national cuts, says Aune.

Still, the Blacks Mountain scientists are optimistic about their work as a prototype for future Forest Service research and resource management. "We all started out wanting to grow wood. Now we know there have got to be a lot of paths for energy (into the ecosystem), some through wood, some through wildlife, some through wildflowers," says Ferrell. "We still don't know much about what's out here, but we have some faith that if we use natural processes we have the best chance of preserving it all in the face of our own ignorance."

JANE BRAXTON LITTLE - a newspaper correspondent and resource expert, lives in Greenville, California.