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PARENT SESSION
Symposium #13: Fire suppression impacts in crown fire ecosystems.
Sponsored by ESA Vegetation Section
Organized by: J. E. Keeley and E. A. Johnson.
Wednesday, August 8, 2001. 8:00 AM to 12:00 PM. Lecture Hall


Wildfire regimes and fire suppression in the North American boreal forest.

Johnson, Edward1, Miyanishi, Kiyoko2, 1 2

ABSTRACT- It is generally believed that as fire suppression becomes successful in the boreal forest, fuel will build up and more severe and destructive fires will result. The fires of recent years are cited as examples of this phenomenon. However, both fire suppression effects and the fuel build-up idea have little support in the scientific literature. The literature shows a fire regime of infrequent, large, lightning-caused, high intensity (kW m-1) fires creating the age distribution of the forest. The forest age distribution reflects several changes in fire frequency over the last 300 years, most correlated to large-scale climate changes. Old-growth still makes up about 5% of the area as it has in the past. The forest remains closed canopied; there has been no change in forest structure as in ponderosa pine ecosystems. There is no evidence that fine and medium fuels increase in older forests.

KEY WORDS: wildfire, suppression, boreal forest