PARENT SESSION
Symposium #24: Adaptive Management Experimentation in Ponderosa Pine Forest Restoration.
Organized by: PZ Fule and PG Friederici
Wednesday, August 7. 1:00 PM to 4:30 PM. Maricopa Meeting Room, TCC.
Estimating ponderosa pine/Douglas-fir landscape structure without fire suppression at Colorado's unlogged Cheesman Lake.
Kaufmann, Merrill*,1, Fornwalt, Paula1, Huckaby, Laurie1, Stoker, Jason1, Romme, William2, 1 USDA Forest Service, Fort Collins, CO2 Dept. of Forest Sciences, Fort Collins, CO
ABSTRACT- An unlogged ponderosa pine/Douglas-fir landscape at Cheesman Lake in the Colorado Front Range historically had a shifting mosaic of low-density forests and transient openings, regulated primarily by mixed-severity fires with a 50-year mean fire interval. Fire exclusion since 1900, however, resulted in denser forests with fewer and smaller openings and more young Douglas-fir trees. Maps of current forest densities were created from aerial photographs. Extensive tree age data from recently sampled plots were used to estimate densities prior to fire suppression. Spatial maps and temporal patterns of six major historical fires prior to 1900 and age data for the oldest trees in mapped polygons provided a means for spatially estimating the severity of past fires. From this, we developed a plausible scenario for the patterns and effects of four fires that occurred but were suppressed in the 20th century. Finally, we used estimates of these fire effects and forest regrowth generated by FVS to create a map of forest densities in 2002 that might have occurred had these fires not been suppressed. Temporal changes in landscape components with and without fire suppression are presented using a simple frame model. This model assumes that four potential conditions exist: (1) openings created by fire and dominated by grass or shrubs, (2) ponderosa pine forests and (3) ponderosa pine/Douglas-fir forests developed following stand-replacing fire, and (4) persistent old-growth forests having no indication of past stand-replacing fire.
KEY WORDS: ponderosa pine, restoration, Cheesman Lake