The March meeting will be about pinyon-juniper dynamics, fuel succession and fire effects: reconciling management objectives with the current state of knowledge. Dr. Peter Weisberg, Professor of Landscape Ecology at University of Nevada, Reno, will be presenting the results of his research.
He will provide a broad overview of what is known about vegetation change and fire ecology of pinyon-juniper woodlands in the Great Basin. Across the range of pinyon-juniper woodland in the western United States there has been a marked increase in area burned and average fire size over the past three decades. However, observed fire rotations have remained within historical ranges as reconstructed by tree-ring based fire history studies, and recent fire regime trends in pinyon-juniper woodlands have been similar to those of other regional land-cover types. Although there has been a strong pattern of woodland expansion since the late 1800s, not all expansion has been ‘invasion’ arising from historical over-grazing and altered fire regimes, but much has been the result of forest recovery processes, natural stand dynamics, and response to changing climate. Furthermore, recent declines in tree cover associated with drought and fire have nearly balanced expansion over the past three decades. Regardless of the underlying cause, changes in relative tree dominance alter fuelbed structure and potential fire behavior. The dominant pinyon-juniper management paradigm – that he will characterize as “landscape restoration from woodland expansion” – needs to be broadened to maintain resilience of the overall landscape mosaic to climate change, fire regime shifts, annual grass invasions, and other inter-related stressors. Certain management objectives, such as reducing the fire risk to communities, can be achieved through silvicultural practices (e.g. density management, surface or canopy fuels reduction, patch cutting to regenerate understory species within landscape mosaics) that maintain a target level of tree cover and do not necessitate large-scale woodland-to-sagebrush conversion. Pinyon-juniper silviculture can be further developed for flexibly achieving a range of management objectives, aimed at restoring and maintaining diverse, fire-resilient, climate-resilient, mosaic landscapes that provide essential habitat, forage and cultural resources.
Peter Weisberg is Professor of Landscape Ecology at University of Nevada, Reno where he’s been on the faculty for 15 years and teaches courses in Natural Resource Ecology, Fire Ecology, and Forest and Range Ecology. He received his BS in Forest Biology from SUNY College of Environmental Science and Forestry, his MS in Biogeography from University of Wyoming, and his PhD in Forest Science from Oregon State University. He and his students have extensively studied natural disturbances such as fire, forest responses to episodic drought, invasive plant species, and plant community response to environmental change and resource management practices, over a broad range of ecosystem types including forests, semi-arid woodlands, riparian and wetland ecosystems, rangelands and deserts. More than a decade of research in Great Basin pinyon-juniper woodlands and sagebrush ecosystems has focused on understanding the dramatic distributional and structural shifts within the woodland and along the woodland-shrubland boundary. Outcomes of these investigations have piqued Dr. Weisberg’s interest in the ecological and resource values associated with tree-dominated vegetation in arid lands.
The March meeting is scheduled for Tuesday March 6th at 6:00 pm at Turtle Rock Park.