The session, which has been organized by Edward Johnson from the University of Calgary and Jon Keeley from the US Geological Survey, will examine the different ways fire moves through various ecosystems types. It has been well established, say Johnson and Keeley, that ecosystems dominated by ponderosa pine have a long history of frequent surface fires and infrequent crown fires. The successful suppression of surface fires by humans during the last century has led to a large accumulation of fuel, which has in turn led to an increase in damaging and uncontrollable fires in the crown areas of trees. In order to manage fire risk, land managers have adopted a method of planned or "prescribed" burns, whereby fires are purposefully set in areas where fire has not recently occurred. Ecologists refer to this as the "ponderosa pine model." While there is evidence that this model may be applicable to some open canopy forests, some scientists question the logic of applying it to all ecosystems. Several speakers at this symposium will present evidence regarding the ineffectiveness of using this model on other systems.
Keeley, Paul Zedler from the University of Wisconsin, and Max Moritz from California Polytechnic State University will present data regarding fire regimes and history in California's shrubland areas. In these systems, there is little evidence that prescribed burns will be effectively used to control fires. Young vegetation has been found to burn easily and frequently and the absence of older vegetation does not seem to reduce the risk of large fires. By examining historical patterns, researchers have also found little evidence to suggest that fire regimes in the past were different that those in contemporary times. Presenters will explore the dominant role that weather may play in fires throughout this region, and also will demonstrate how shifting human demographics have placed increasing demands on fire suppression efforts in California.
Three other speakers will present data on fire history in boreal forests. Johnson, Simon Bridge (Ontario Ministry of Natural Resources) and Anders Granstrom (Swedish University of Agricultural Sciences) will explore how fire history in these closed canopy northern pine forests differs from the ponderosa pine model. Again, the scientists say there is little evidence that these areas burned frequently in the past. Instead, data suggest that a regime of infrequent, large, lightening-caused, high intensity fires dictated the age distribution of trees commonly found in the area. Presenters will demonstrate that the role of large scale climate changes have correlated with changes in fire frequency. European records going back as far as 700 years will be used to validate this argument. Bridge will also show how techniques currently used to measure fire frequency may be unable to detect small scale fires that occur regularly in boreal regions. Management implications for northern regions will also be examined.
For more information about this session, and all ESA Annual Meeting activities, visit the ESA website: http://esa.sdsc.edu/madison. Held in scenic Madison, Wisconsin the theme of the meeting is "Keeping all the Parts." Over 3,000 scientists are expected to attend.
The Ecological Society of America (ESA) is a scientific, non-profit, 7,800-member organization founded in 1915. Through ESA reports, journals, membership research, and expert testimony to Congress, ESA seeks to promote the responsible application of ecological data and principles to the solution of environmental problems. ESA publishes three scientific, peer-reviewed journals: Ecology, Ecological Applications, and Ecological Monographs. Information about the Society and its activities is published in the Society's quarterly newsletter, ESA NewSource, and in the quarterly Bulletin. More information can be found on the ESA website: http://esa.sdsc.edu.
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