Abstract
This study evaluates the physical characteristics and predicted hydrologic function in response to the removal of Pinus contorta – var. latfolia (commonly referred to as lodgepole pine trees) in Timothy Meadow located in the northern Sierra Nevada, Eldorado County, California. Forest Service managers in the Eldorado National Forest are presently considering the removal of lodgepole pine trees that have encroached on the meadow in an effort to increase the amount of groundwater storage in meadow sediments. Previous work in vegetation management as it relates to groundwater storage has been conducted in other parts of the country with differing results following tree harvesting. The results of these studies appear to indicate that the effectiveness of vegetation removal correlates to the hydrologic functionality of the meadow or wetlands prior to removal. Timothy Meadow offered a unique opportunity to study the predicted response of a hydrologically functional meadow to simulated removal of lodgepole pine trees. The physical characteristics of Timothy Meadow that were measured include: surface area, sediment thickness, specific yield and permeability of subsurface materials, and potential water storage volume. A groundwater flow model was constructed to predict the change in water table elevations to the removal of lodgepole pine transpiration from the groundwater budget. Results suggest that subsurface storage increases significantly in response to tree removal during the summer months when transpiration, should the trees be left in place, would be the greatest. This study addresses questions that have broad implications for vegetation management as it relates to water resources as much of California receives water from Sierra high elevation watersheds. The results of this study will be used to inform Forest Service management throughout Northern California as to the effectiveness of vegetation removal as a remedial alternative.