Interesting lecture coming up. If anyone here can go, please post a report on what you see and hear.
Restoring pattern to frequent fire forests with variable-density thinning: implementation and initial outcomes
Thursday, May 2, 2019
1:00 PM 2:00 PM
University of California-Davis Asmundson Hall “Big Hannah” (Room 242) Davis, CA
In the abstract for the lecture, I highlighted text that demonstrates the outcomes of such thinning. These treatments are needed throughout the west, including spotted owl habitat. I am mystified why anyone would oppose such management and claim it is “industrial logging” designed to line the coffers of timber companies.
Abstract: Historical forests shaped by fire were highly heterogeneous at the within-stand scale, with dense groups of trees and individual trees interspersed with numerous small gaps. Stem maps from research plots on the Stanislaus National Forest dating to 1929 show that prior to any logging, canopy cover was 45% and over 20% of the area within stands was in canopy gaps where shrubs were abundant. As a result of past logging and fire exclusion, the contemporary stands were denser and more homogeneous, with no gaps and very low shrub cover. To improve resilience to disturbances such as wildfire or drought, while better balancing the needs of associated plant and animal species, we utilized the historical structure as a guide to a ‘variable density’ thinning prescription, comparing this with a standard thinning to an even tree crown spacing, and an unthinned control. Half of the units were then treated with prescribed fire. Mechanical thinning removed 40% of the basal area, and by favoring pines over fir and cedar, produced a species composition similar to the historical reference condition. Variable thinning enhanced within-stand structural heterogeneity and did so at spatial scales similar to heterogeneity found in historical stands. Both thinning treatments experienced significantly less tree mortality during the recent drought than unthinned controls. In addition, understory shrubs and grasses are already much more abundant, especially where thinning was followed by prescribed fire. While still early, it is our hope that the variable density thinning with prescribed fire treatment will not only be more resilient to future wildfires and droughts, but also produce conditions suitable for a greater diversity of species. [emphasis added]