Collapse_ How Societies Choose to Fail or Succeed - Jared Diamond [27]
Of course, though, loggers concentrated on removing those big, old, valuable, fire-resistant Ponderosa Pines, while fire suppression for decades let the understory fill up with Douglas Fir saplings that would in turn become valuable when full-grown. Tree densities increased from 30 to 200 trees per acre, the forest’s fuel load increased by a factor of 6, and Congress repeatedly failed to appropriate money to thin out the saplings. Another human-related factor, sheep grazing in national forests, may also have played a major role by reducing understory grasses that would otherwise have fueled frequent low-intensity fires. When a fire finally does start in a sapling-choked forest, whether due to lightning or human carelessness or (regrettably often) intentional arson, the dense tall saplings may become a ladder that allows the fire to jump into the crowns. The outcome is sometimes an unstoppable inferno in which flames shoot 400 feet into the air, leap from crown to crown across wide gaps, reach temperatures of 2,000 degrees Fahrenheit, kill the tree seed bank in the soil, and may be followed by mudslides and mass erosion.
Foresters now identify the biggest problem in managing western forests as what to do with those increased fuel loads that built up during the previous half-century of effective fire suppression. In the wetter eastern U.S., dead trees rot away more quickly than in the drier West, where more dead trees persist like giant matchsticks. In an ideal world, the Forest Service would manage and restore the forests, thin them out, and remove the dense understory by cutting or by controlled small fires. But that would cost over a thousand dollars per acre for the one hundred million acres of western U.S. forests, or a total of about $100 billion. No politician or voter wants to spend that kind of money. Even if the cost were lower, much of the public would be suspicious of such a proposal as just an excuse for resuming logging of their beautiful forest. Instead of a regular program of expenditures for maintaining our western forests in a less fire-susceptible condition, the federal government tolerates flammable forests and is forced to spend money unpredictably whenever a firefighting emergency arises: e.g., about $1.6 billion to fight the summer 2000 forest fires that burned 10,000 square miles.
Montanans themselves hold diverse and often self-contradictory views about forest management and forest fires. On the one hand, the public fears and instinctively dislikes the “let it burn” response that the Forest Service is forced to take towards huge fires that would be dangerous or impossible to try to extinguish. When the 1988 fires in much of Yellowstone National Park were allowed to burn, the public was especially loud in its protests, not understanding that in fact there was nothing that could be done except to pray for rain or snow. On the other hand, the public also dislikes proposals for forest thinning programs that could make the forests less flammable, because people prefer beautiful views of dense forests, they object to “unnatural” interference with nature, they want to leave the forest in a “natural” condition, and they certainly don’t want to pay for thinning by increased taxes. They (like most foresters until recently) fail to understand that western forests are already in a highly unnatural condition, as the result of a century of fire suppression, logging, and sheep grazing.
Within the Bitterroot, people build trophy homes next to or surrounded by flammable forests at the urban/wildland interface and then expect the government to protect those homes against fires. In July 2001, when my wife and I went for a hike west of the town of Hamilton