2003 Veblen, T.T. Key issues in fire regime research for fuels management and ecological restoration. Pages 259-276 in: P. Omi and L. Joyce (technical eds). Fire, Fuel Treatments and Ecological Restoration: Conference proceeedings; 2002 16-18 April; Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 475 p. AN INTRODUCTION TO KEY ISSUES IN FIRE REGIME RESEARCH FOR FUELS MANAGEMENT AND ECOLOGICAL RESTORATION Thomas T. Veblen Department of Geography University of Colorado Boulder, Colorado 80301 Email: [email protected] Paper prepared for the Conference on Fire, Fuel Treatments and Ecological Restoration: Proper place, Appropriate Time, April 16-18, 2002, Fort Collins, Colorado Abstract. The basic premise behind many projects aimed at wildfire hazard reduction and ecological restoration in forests of the western United States is the idea that unnatural fuel buildup has resulted from suppression of formerly frequent fires. This premise and its implications need to be critically evaluated by conducting area-specific research in the forest ecosystems targeted for fuels or ecological restoration projects. Fire regime researchers need to acknowledge the limitations of fire history methodology and avoid over-reliance on summary fire statistics such as mean fire interval and rotation period. While fire regime research is vitally important for informing decision making in the areas of wildfire hazard mitigation and ecological restoration, there is much need for improving the way researchers communicate their results to managers and the way managers use this information.INTRODUCTION The two major management themes of this conference are: 1) fuel treatments for the purpose of reducing fire hazard, and 2) ecological restoration through a variety of management practices including prescribed fire. The title and content of the conference might lead to the impression that fire hazard reduction through fuel treatments and ecological restoration have convergent objectives in all forest ecosystems in the western United States. However, this implication needs to be explored on the basis of existing knowledge of historical fire regimes and forest conditions on a case by case basis for different forest cover types and different locations. In some forest ecosystems fire hazard reduction through fuels management may be achieved by restoring historic fire regimes of frequent surface fires. However, in other forest ecosystems, historic fire regimes included widespread stand-replacing fires at long intervals. In those systems, restoration of the historic fire regime will not reduce the hazard to property and humans. This essay introduces a series of papers on fire regimes by identifying some of the key issues and research challenges for fire regime research. Political leaders and many resource management professionals often stress the the convergence of the goals and strategies of fire hazard reduction and ecological restoration in the forests of the western United States. For example, the official position of the Society of American Foresters in response to the 2000 fire season included the statement that: “The buildup of combustible materials (fuels) in the forests of the West is at an all-time high. Much of this can be attributed to the decades of fire suppression that allowed the fuels to build up so fires will now burn bigger and hotter than ever” -- Society of American Foresters, August 11, 2000 press release. There is a widespread belief among resource managers, reflected by many of the papers presented in the current conference, that fuel accumulation during many years of fire suppression in western forests was the major cause of the widespread wildfires of the 2000 season. Likewise, there is a consensus that a perceived decline in “forest health” (tree diseases, mistletoe infection, and forest insect pests) is the result of fire exclusion. One of the leading experts on ecological restoration in western U.S. forests has written: “The dry forest ecosystems of the American West, especially those once dominated by open ponderosa pine forest, are in widespread collapse. We are now witnessing sudden leaps in aberrant ecosystem behaviour long predicted by ecologists and conservation professionals (see Nature 407, 5; 2000). Trends over the past half-century show that the frequency, intensity and size of wildfires 2will increase – by orders of magnitude – the loss of biological diversity, property and human lives for many generations to come.” -- Covington 2000, p. 135. The view that current fire hazard is largely attributable to fuel buildup under decades of fire exclusion is strongly reflected in the following passage from the National Fire Plan: “While the policy of aggressive fire suppression appeared to be successful, it set the stage for the intense fires that we see today. ...after many years of suppressing fires, thus disrupting normal ecological cycles, changes in the structure and make-up of forests began to occur. Species of trees that ordinarily would have been eliminated from forests by periodic, low-intensity fires began to become a dominant part of the forest canopy. Over time, these trees became susceptible to insects and disease. Standing dead and dying trees in conjunction with other brush and downed material began to fill the forest floor. The resulting accumulation of these materials, when dried by extended periods of drought, created the fuels that promote the type of wildfires that we have seen this year. In short, decades of aggressive fire suppression have drastically changed the look and fire behavior of Western forests and rangelands. Forests a century ago were less dense and had larger, more fire-resistant trees. For example, in northern Arizona, some lower elevation stands of ponderosa pine that once held 50 trees per acre, now contain 200 or more trees per acre. In addition, the composition of our forests have changed from more fire-resistant tree species to non-fire resistant species such as grand fir, Douglas-fir, and subalpine fir. As a result, studies show that today’s wildfires typically burn hotter, faster, and higher than those of the past.”-- National Fire Plan 2001. While the National Fire Plan also recognizes the importance of other contributing factors to our current wildfire management crisis, including weather influences (i.e.