Title

Contrasting Effects of Wildfire and Ecological Restoration in Old-Growth Western Larch Forests

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Presentation

Abstract

Two western larch forests were studied to compare the effects of a wildfire and a restoration project (mechanical thinning and prescribed burn) to contrast forest characteristics pre- and post-disturbance at both sites. The sites chosen for this study were the Girard Grove of the Swan Ranger District near Seeley Lake, Montana, where a restoration project occurred in 2003 for the purpose of mimicking a historical mixed-severity fire regime; and the river valley of the South Fork of the Flathead, in the Bob Marshall Wilderness, where a mixed-severity wildfire occurred in 2003. Using a laser measuring device we were able to catalogue the graphical (X,Y) location of every tree and snag on a one-hectare plot at each site, for extrapolating forest spatial patterns before and after the two disturbances. A study to assess ecologically significant spatial patterns in western larch forests has never been done, especially a comparison between pre- and post-disturbance sites. We also gathered the diameter at breast height, tree type, and vitality of each tree. Then, using three 100 meter transects, we collected data on down woody debris (DWD) size, species, and decay. Using the same transects, we formed circle plots documenting sapling regeneration numbers and vitality based on height. These results show that the Restoration site did not ecologically share valuable characteristics possessed by the Wildfire site. The Restoration site possessed fewer saplings by a factor of four, with sapling growth being one of the major objectives of the project. Though soil ground cover data was not collected, we hypothesize that the Wildfire site displayed greater sapling numbers and vitality due to the severity of the burn creating bare mineral soil, valuable to larch sapling regeneration. Analysis of forest spatial patterns has revealed that the restoration project was weak compared to the Wildfire site and management goals.

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Apr 12th, 2:20 PM Apr 12th, 2:40 PM

Contrasting Effects of Wildfire and Ecological Restoration in Old-Growth Western Larch Forests

UC 331

Two western larch forests were studied to compare the effects of a wildfire and a restoration project (mechanical thinning and prescribed burn) to contrast forest characteristics pre- and post-disturbance at both sites. The sites chosen for this study were the Girard Grove of the Swan Ranger District near Seeley Lake, Montana, where a restoration project occurred in 2003 for the purpose of mimicking a historical mixed-severity fire regime; and the river valley of the South Fork of the Flathead, in the Bob Marshall Wilderness, where a mixed-severity wildfire occurred in 2003. Using a laser measuring device we were able to catalogue the graphical (X,Y) location of every tree and snag on a one-hectare plot at each site, for extrapolating forest spatial patterns before and after the two disturbances. A study to assess ecologically significant spatial patterns in western larch forests has never been done, especially a comparison between pre- and post-disturbance sites. We also gathered the diameter at breast height, tree type, and vitality of each tree. Then, using three 100 meter transects, we collected data on down woody debris (DWD) size, species, and decay. Using the same transects, we formed circle plots documenting sapling regeneration numbers and vitality based on height. These results show that the Restoration site did not ecologically share valuable characteristics possessed by the Wildfire site. The Restoration site possessed fewer saplings by a factor of four, with sapling growth being one of the major objectives of the project. Though soil ground cover data was not collected, we hypothesize that the Wildfire site displayed greater sapling numbers and vitality due to the severity of the burn creating bare mineral soil, valuable to larch sapling regeneration. Analysis of forest spatial patterns has revealed that the restoration project was weak compared to the Wildfire site and management goals.