Wednesday, March 21, 2012
Ross W. Gorte
Specialist in Natural Resources Policy
Specialist in Agricultural Conservation and Natural Resources Policy
Congress continues to face questions about forestry practices, funding levels, and the federal role in wildfire protection. Recent fire seasons have been, by most standards, among the worst in the past half century. National attention began to focus on wildfires when a prescribed burn in May 2000 escaped control and burned 239 homes in Los Alamos, NM. President Clinton responded by requesting a doubling of wildfire management funds, and Congress enacted much of this proposal in the FY2001 Interior appropriations act (P.L. 106-291). President Bush responded to the severe 2002 fires by proposing a Healthy Forests Initiative to reduce fuel loads by expediting review processes.
Many factors contribute to the threat of wildfire damages. Two major factors are the decline in forest and rangeland health and the expansion of residential areas into wildlands—the wildlandurban interface. Over the past century, aggressive wildfire suppression, as well as past grazing and logging practices, have altered many ecosystems, especially those where light, surface fires were frequent. Many areas now have unnaturally high fuel loads (e.g., dead trees and dense thickets) and an historically unnatural mix of plant species (e.g., exotic invaders).
Fuel treatments have been proposed to reduce the wildfire threats. Prescribed burning—setting fires under specified conditions—can reduce the fine fuels that spread wildfires, but can escape and become catastrophic wildfires, especially if fuel ladders (small trees and dense undergrowth) and wind spread the fire into the forest canopy. Commercial timber harvesting is often proposed, and can reduce heavy fuels and fuel ladders, but exacerbates the threat unless and until the slash (tree tops and limbs) is properly disposed of. Other mechanical treatments (e.g., precommercial thinning, pruning) can reduce fuel ladders, but also temporarily increase fuels on the ground. Treatments can often be more effective if combined (e.g., prescribed burning after thinning). However, some fuel treatments are very expensive, and the benefit of treatments for reducing wildfire threats depend on many factors.
It should also be recognized that, as long as biomass, drought, lightning, and high winds exist, catastrophic wildfires will occur. Only about 1% of wildfires become conflagrations, but which fires will “blow up” into crown wildfires is unpredictable. It seems likely that management practices and policies, including fuel treatments, affect the probability of such events. However, past experience with wildfires are of limited value for building predictive models, and research on fire behavior under various circumstances is difficult, at best. Thus, predictive tools for fire protection and control are often based on expert opinion and anecdotes, rather than on research evidence.
Individuals who choose to build homes in the urban-wildland interface face some risk of loss from wildfires, but can take steps to protect their homes. Federal, state, and local governments can and do assist by protecting their own lands, by providing financial and technical assistance, and by providing relief after the fire.
Date of Report: March 7, 2012
Number of Pages: 27
Order Number: RL30755
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Posted by Penny Hill Press, Inc. at Wednesday, March 21, 2012