Williams and Baker’s new study found that open and park-like conditions were not common historically and that high-severity fire used to be much more common in these forests than it is today. Finally, Williams and Baker conclude that current efforts to reduce trees and understory vegetation in these forests under the label of “restoration” would actually move the forests outside of their historical range of variability and harm biodiversity.
New study challenges forest restoration and fire management in western dry forests
February 16, 2012. Laramie, Wyoming. New research shows that western dry forests were not uniform, open forests, as commonly thought, before widespread logging and grazing, but included both dense and open forests, as well as large high-intensity fires previously considered rare in these forests. The study used detailed analysis of records from land surveys, conducted in the late-1800s, to reconstruct forest structure over very large dry-forest landscapes, often dominated by ponderosa pine forests. The area analyzed included about 4.1 million acres on the Mogollon Plateau and Black Mesa in northern Arizona, in the Blue Mountains in northeastern Oregon, and in the Colorado Front Range.
The reconstructions, which are based on about 13,000 first-hand descriptions of forests from early land surveyors along section-lines, supplemented by data for about 28,000 trees, do not support the common idea that dry forests historically consisted of uniform park-like stands of large, old trees. Previous studies that found this were hampered by the limitations inherent in tree-ring reconstructions from small, isolated field plots that may be unrepresentative of larger landscapes.
“The land surveys provide us with an unprecedented spatially extensive and detailed view of these dry-forest landscapes before widespread alteration” said Dr. William Baker, a co-author of the study and a professor in the Program in Ecology at the University of Wyoming. “And, what we see from this is that these forests were highly variable, with dense areas, open areas, recently burned areas, young forests, and areas of old-growth forests, often in a complex mosaic.”