"We need to prepare the forest… Then we can begin to bring fire back into the ecosystem in a more naturally-occurring condition. That is, the fire would…be burning with flame lengths of one or two or three feet, instead of flame lengths of two or three hundred feet."
Kern: Could you give us a summary of the status of the forest in this area right now?
Smith: Uh-huh. Yeah, the forests in Arizona and New Mexico, of the Southwest, are grossly overstocked with trees. In the presettlement times, there were like 20 or 30 or 50 trees per acre, and now we have 500, 600, 800, 1,000 trees per acre. It's terribly understocked with grasses, flowering plants, herbaceous plants, shrubs, and the like. In presettlement times, those understory plants—grasses and forbs and shrubs—made up about 70 percent of the forested area. Today, almost a hundred percent of the forest is in trees.
This has changed the character of fire for the Southwest in a very dramatic way, because prior to Euro-American settlement, fires would burn through the ecosystem frequently—every two or three or five or eight years there would be fire burning on every forest in the Southwest. As it did that, it would burn up the fuel available for fire, leaving only enough fuel in three years to burn again. Today, because of management practices, we have now converted the forest into almost all trees, and we have managed to suppress or exclude fire from almost all of these acres, so now when fire burns, it rapidly gets into the crowns of the trees, it burns much more intensively, much hotter, much longer, and much more destructively to the ecosystem. So our forests are way out of whack. We have too many trees, not enough fire, not enough of the understory vegetation.
But before we can get fire back into the ecosystem, we need to prepare the forest. We need to thin it, we need to get it so that the fires don't rapidly escalate into the tops of the trees and become crown fires, and we need to regenerate the understory of grasses and forbs and shrubs. Then we can begin to bring fire back into the ecosystem. That is, the fire would be burning in a more natural condition, be burning with flame lengths of one or two or three feet, instead of flame lengths of two or three hundred feet. Then fire will not be as destructive as the fires that we've had more recently. We need to make those adjustments to the fuels and to the character and structure of the forest.