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Modeling historical range of variability and alternative management scenarios in the upper Yuba River watershed, Tahoe National Forest, California

Posted date: February 22, 2019
Publication Year: 
2018
Authors: McGarigal, Kevin; Mallek, Maritza; Estes, Becky; Tierney, Marilyn; Walsh, Terri; Thane, Travis; Safford, Hugh; Cushman, Samuel A.
Publication Series: 
General Technical Report (GTR)
Source: Gen. Tech. Rep. RMRS-GTR-385. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Stations. 346 p.

Abstract

This report describes modeling of historical range of variability and alternative management scenarios in the upper Yuba River watershed, Tahoe National Forest, California. We discuss the need for this study with respect to the historical and contemporary context of the northern Sierra Nevada landscape, including background on the range of variability concept and the use of simulation modeling to quantify it. We simulated the dynamics in vegetation driven by wildfire during the historical reference period (ca. 1550-1850). Based on the output, we quantified the range of variability in composition and configuration of the landscape mosaic, and compared the results to the current landscape to quantify departure. We also created a set of eight alternative management scenarios reflecting different objectives and applying different treatment types and intensities. We conducted 20 replicate 100-year simulations of each of these management scenarios and quantified the range of variability in landscape composition and configuration, as before, for each scenario. We compared the range of variation in each landscape attribute among management scenarios and with the historical range of variability and current landscape to determine the potential for management scenarios to move the current landscape toward its historical range of variability. We provide a synopsis of the major findings or “take-home” messages of this study and their management implications. For example, our scenario analysis demonstrates that active vegetation management involving a combination of mechanical and prescribed fire treatments has the potential to emulate many aspects of landscape structure that would occur under a natural disturbance regime, but it would require a much higher intensity of treatment than we are accustomed to - perhaps as much as 10 times the current treatment rate.

Citation

McGarigal, Kevin; Mallek, Maritza; Estes, Becky; Tierney, Marilyn; Walsh, Terri; Thane, Travis; Safford, Hugh; Cushman, Samuel A. 2018. Modeling historical range of variability and alternative management scenarios in the upper Yuba River watershed, Tahoe National Forest, California. Gen. Tech. Rep. RMRS-GTR-385. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Stations. 346 p.