DRY vegetation. Oxygen. Intense heat. The fundamentals of wildfire are primitive, as are the means of stopping it - mostly hand tools and prop-driven airplanes that drop chemicals.
''It's not rocket science here,'' says Skip Scott, who started smoke-jumping as a college student in 1969 and now heads the National Interagency Fire Center in Boise, Idaho.
But as hearty men and women, lugging heavy gear and a ''can-do'' spirit, head out to fight a new set of blazes a year after what officials call the ''most intense'' fire season in United States history, policymakers are reexamining the science of fire and its role in the ecology of the Western landscape.
For the last 85 years, a strict, no-burn policy has been the standard in the West, but experts now say this is a flawed way to protect the landscape.
''We must recognize that wildfire has historically been a major force in the evolution of our wildlands, and it must be allowed to continue to play its natural role where possible,'' states a draft proposal by the federal Departments of the Interior and Agriculture recently released for public comment.
''The task before us - reintroducing fire - is both urgent and enormous,'' the proposal reads.
It is also politically flammable. A policy of letting wildfires burn raises a myriad of issues, such as air quality, endangered species protection, and the potential loss of marketable timber.
Closely related is the growing competition between nature and human development in what bureaucrats call the ''wildland/urban interface,'' as Western towns mushroom and ''ranchettes'' sprout. And most controversially, there's always the possibility that a ''prescribed fire,'' one set intentionally, can rage out of control to become an ''escaped fire.''
''It's easy to convince people that fire is destructive,'' says Steep Weiss, a US Bureau of Land Management forester based in Carson City, Nev. ''The explanation of fire's beneficial role is more complicated.''
A change for the worse
The problem, experts say, is that since 1910, when 5 million acres burned in the West, claiming 79 firefighters, the no-burn policy has changed the environment to make it more dangerous.
''Across the entire Western landscape from the Mexican to the Canadian border, scrub trees are taking over,'' asserts Interior Secretary Bruce Babbitt. ''Junipers advance across lowland plains; doghair ponderosa fill gaps in the highland forests; spruce and fir crowd out aspen groves.
''Why are our Western forests and rangelands changing so dramatically?'' asks Mr. Babbitt in an article he wrote recently for American Forests magazine.
''Because we have systematically removed the natural flame. Just as we wiped out the wolf that preyed on weak, sick, and overpopulated herds, we have eliminated the frequent, light-burning fire cycles that used to thin the forests of young trees, kill off the spreading juniper seedlings, and hold brush in check.''
Spread of firestorms
Throughout the 11 Western states, according to the recent draft policy statement on wildland- fire management, ''there are 20 [million] to 30 million acres of federal lands where conditions are ripe for extremely intense, destructive wildfires.''
Over the past decade, an average of 67,043 fires a year have burned more than 2.7 million acres each fire season, an area nearly the size of Connecticut.
With the buildup of forest fuels, regular low-intensity fires have been replaced by catastrophic blazes like the one that swept through Yellowstone National Park in 1988, burning more than 1 million acres.
Or as University of Washington professor of forestry James Agee has said, ''The friendly flame has been replaced by the firestorm,'' in which clusters of small trees and brush become fire ladders carrying conflagration into the tops of larger, older trees.
Such blazes then can become ''crown fires'' jumping from treetop to treetop, racing along at 20 miles an hour or more. This is what happened a year ago in Colorado when 14 firefighters trying to outrun the flames were killed in what investigators called a ''major blowup.''
Those lost in the Storm King Mountain fire, including nine men and women in an elite ''hotshot'' crew from Prineville, Ore., were honored last week when a memorial park was dedicated in Glenwood, Colo.
Official investigations of the tragedy blamed supervisors for compromising or violating the ''Standard Fire Orders'' and ''Watch Out Situations'' listed on the survival checklist that wildlands firefighters carry. As a result, administrators are being admonished to create a ''passion for safety'' among firefighting units.
''People dying is not acceptable,'' says the National Interagency Fire Center's Mr. Scott, who spent 10 years of his career ''jumping out of perfectly good airplanes'' to fight fires in Alaska. But despite heightened awareness and intensified training, he adds, firefighting remains ''an inherently dangerous profession ... a long, dirty, physically arduous job.''
A tour of the equipment storage facility in Boise (one of 11 such caches around the West) gives a clue of the kind of work involved. Stored neatly are stacks of water pumps, chain saws, disposable-paper sleeping bags, boxes of MREs (''meals ready to eat,'' that the military uses), radio gear, emergency shelters of heat-reflective material shaped like pup tents, and hand tools, including the ax-hoe combination named for Edward Pulaski, a Forest Service ranger who fought the 1910 fires in the Rocky Mountains.
These days, firefighters also get a high-tech hand from aerial infrared mapping, solar-powered remote automated weather stations (RAWS), and an automatic-lightning detection system (ALDS) that can pinpoint lightning strikes 225 miles away.
It's not unusual to have 50,000 strikes on a typical summer day in the West, with as many as 110,000 having been recorded in one 24-hour period.
In recent years, land-management agencies have been making increased use of prescribed burns to reduce the risk of wildfire.
Of the 633 million acres in the US controlled by the Forest Service, the Bureau of Land Management, the Park Service, and the Fish and Wildlife Service, some 580,000 acres are burned on purpose each year, most of that in the South.
As times and policies change, however, this may be just the beginning of using fire as a tool.
Those investigating last year's Storm King Mountain fire in Colorado asserted that ''fuels management, especially through the reintroduction of fire as an integral part of natural-resource management, must be a high priority of the Departments of the Interior and Agriculture.''
But experts also realize that this could be a tough sell with the public, especially those generations raised on Bambi and Smokey the Bear, admonishing everybody that ''only YOU can prevent forest fires.''