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February 24, 2016   | 10:00 AM

Conifer Expansion: Science and Management

Goal: To provide land managers and others with a summary of the effects of conifer expansion into sagebrush ecosystems, the potential for management, and on-going research.

Background: Over the past 150 years, juniper (Juniperus spp.) and pinyon (Pinus spp.) woodlands have increased in area across the sagebrush steppe of the west. Effects have been especially pronounced in the Great Basin where the area occupied by woodlands has increased up to 625% (Miller et al. 2008). Causes include a combination of human-induced interruptions to natural wildfire cycles and favorable climatic periods. The proliferation of trees has led to infill of many pre-settlement woodlands and sagebrush/tree savanna communities. In addition, juniper and pinyon have expanded into sagebrush sites that previously did not support trees, resulting in a gradual shift in land cover type from shrub steppe to woodland. As much as 90 percent of this change has occurred in areas that were previously sagebrush vegetation types (Miller et al. 2011). This transition has broad impacts on ecosystem function and services, prompting widespread management concern. As woodland succession progresses, conifers use much of the available soil water, which allows them to outcompete native grasses, forbs, and shrubs. Increases in conifer cover and decreases in understory vegetation may result in soil erosion on slopes, leading to reduced site productivity and resilience to disturbance. Woodland succession also affects fire behavior as shrub-steppe ground fuels decline but conifer canopy fuels increase, resulting in fewer, but more intense wildfires, and increasing the potential for invasive annual grasses to dominate on warmer sites. Conifer expansion and infill are also a threat to shrub-obligate wildlife species.

Topics: Where to treat, when to treat, how to treat, how to manage treated areas, and expected benefits (based on treatment type, and scale - maintaining native understory plants, reducing risk of large and severe wildfires, improving habitat for declining species, reducing soil erosion and conserving soil water, and increasing ecosystem resilience to fire and resistance to cheatgrass invasion.

Session Lead: Terry Messmer
Utah State University, Wildland Resources Dept., 5230 Old Main Hill, Logan, UT 84322-5230; 435-797-3975;

Terry A. Messmer is the Director of the Jack H. Berryman Institute, holds the Quinney Professorship of Wildlife Conflict Management in the College of Natural Resources, and is the Director of the Utah Community-Based Conservation Program at Utah State University. His research, teaching, and extension activities include identification, implementation, and evaluation of conservation strategies, technologies, and partnerships that can benefit agriculture, wildlife, and resource stakeholders.

Speakers Include:

Effects of Conifer Expansion and Associated Thresholds on Woodland Health and Future Research Needs
Robin J. Tausch
and K. Pelz
Robin J. Tausch is an Emeritus Range Scientist with the US Forest Service, Rocky Mountain Research Station, Reno, NV 89512;;

Robin J. Tausch is an Emeritus Range Scientist with the US Forest Service, rocky Mountain Research Station, Reno, Nevada. His research is on the ecology and paleoecology of pinyon-juniper woodlands and associated sagebrush ecosystems. He is investigating how these ecosystems have changed in the past, are currently changing, and how they could change into the future in response to ongoing disturbances and changing climate, and to identify future management and research needs.

Plant Community Response to Pinyon-Juniper Reduction in Utah
Thomas A. Monaco
, K. Gunnell, E Thacker, and T. Messmer
Thomas A. Monaco, PhD, Research Ecologist, Forage and Range Research Lab, Utah State University, Logan, UT 84322-6300;

Functional Response of Greater Sage-grouse (Centrocercus urophasianus) Female Vital Rates to Pinyon-Juniper Removal in Northwest Utah.
Charles P. Sandford
, M.T. Kohl, T.A Messmer, D.K. Dahlgren, A. Cook, and B.R. Wing, Charles (Charlie) Sandford, Graduate Research Assistant, Department of Wildland Resources
5230 Old Main Hill, Utah State University, Logan, UT, 84322;

Charlie is completing a Master's in Wildlife Biology. He graduated from New Mexico State University, with a Bachelor's in Wildlife Management and a minor in Range Science in 2012. He has worked as a wildlife technician with the BLM for 2 years in New Mexico, the USFS in Montana, and most recently on a sage-grouse research project with Montana Fish, Wildlife, and Parks. Charlie is researching the vital rate response of sage-grouse to juniper encroachment and removal.

Woody expansion on western rangelands: Prairie grouse as focal species for strategic ecosystem restoration
Jeremy Maestas
, D. Naugle, C. Hagen, M. Falkowski, P. Donnelly, J. Tack, A. Holmes and T. Griffiths
Jeremy Maestas, Sagebrush Ecosystem Specialist, USDA-Natural Resources Conservation Service, West National Technology Support Center, Portland, Oregon; Phone;

Jeremy works with NRCS staff and partners to put science into practice through strategic habitat conservation delivery in sagebrush ecosystems across the West. He grew up in Nevada and went on to earn B.S. and M.S. degrees in Wildlife Biology from Colorado State University. Much of his career has focused on sustaining working landscapes in the Great Basin, where contributions have included implementation of large-scale strategic approaches to reducing conifer encroachment, wildfire and invasive species threats to sagebrush ecosystems.

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