Herbivory, Stand Condition, and Regeneration Rates of Aspen on Burned and Unburned Plots in the Little Mountain Ecosystem Area
Dates
Start Date
2009
Summary
Since 1990, more than 2 million dollars has been spent on habitat-restoration and enhancement projects in the Little Mountain Ecosystem. Many of these efforts have focused on restoring aspen communities to maintain or improve water quality and to enhance ungulate habitat. During 2009, biologists from the WGFD Green River Regional Office established long-term monitoring plots on Little Mountain to evaluate whether the increased number of ungulates using those stands is in balance with targets set for aspen regeneration. The WGFD is collecting data for developing an index of live to dead trees. The USGS is supporting this effort by measuring stand composition to study herbivory patterns at locations associated with historical burns (wildfires [...]
Summary
Since 1990, more than 2 million dollars has been spent on habitat-restoration and enhancement projects in the Little Mountain Ecosystem. Many of these efforts have focused on restoring aspen communities to maintain or improve water quality and to enhance ungulate habitat. During 2009, biologists from the WGFD Green River Regional Office established long-term monitoring plots on Little Mountain to evaluate whether the increased number of ungulates using those stands is in balance with targets set for aspen regeneration. The WGFD is collecting data for developing an index of live to dead trees. The USGS is supporting this effort by measuring stand composition to study herbivory patterns at locations associated with historical burns (wildfires and prescribed fires) and at unburned locations. In 2009, burned and unburned stands were randomly selected based on the stand size (patch area and shape) and stand location (Aspen Mountain, Pine Mountain, and Miller Mountain) across a gradient of conditions and extent of conifer encroachment. Measurements of stand composition collected by the USGS include dominant and subdominant canopy structure, size classification, age structure, regeneration, and conifer encroachment.
Sampling efforts were expanded in 2010 at 60 additional sites on Little Mountain to evaluate aspen condition and stand composition based on different ecological and hydrological settings. In 2011, efforts were focused on recording tree heights and retrieving core and disc samples from aspen and conifers within each plot. During 2012, all samples were examined under a microscope using cross dating and other standard dendroecological methods. A calibrated slide bench was used to develop master ring-width chronologies. Age chronologies and establishment dates were reconstructed for aspen and common conifer species. We also initiated analyses of the relationships between tree age (for aspen and conifers) and tree height and diameter. This information will be used to ascertain establishment dates for aspen and conifers, trends associated with canopy dominance, and growth rates. Information from these sites also was used to support mapping of aspen across Little Mountain. Findings and related map products are being shared with the WLCI Sweetwater County LPDT to support conservation planning and the development of aspen-habitat treatments. An index of aspen sucker density and growth rate will be developed for establishing regeneration benchmarks by which to gage the effectiveness of future treatments across the WLCI area. Partners on this project include the BLM Rock Springs Field Office, WGFD, and the Wyoming Natural Diversity Database.
Product Completed in FY2012
Datasets of establishment dates and age chronologies for 908 samples of aspen and conifer.
Products Completed in FY2011
2011 dataset with tree height and dbh measurements, and plot photos.
Products Completed in FY2009
Spatial data of monitoring plots and photo points.