Fire history and stand structure of a Central Nevada pinyon-juniper woodland

John Bauer, Graduate Research Assistant, University of Nevada - Reno , Ecology, Evolution and Conservation Biology Program

Dr. Peter Weisberg, Assistant Professor of Landscape Ecology, University of Nevada - Reno, Department of Natural Resources and Environmental Science

Abstract: In the past 10 years, a generalized view of fire's historic role in pinyon-juniper (PJ) woodlands of the North American Southwest and Great Basin has evolved into a recognition of large variations in the historic fire regime, driven in part by climatic and topographic differences. Little research has been conducted into fire's role in shaping Great Basin woodlands dominated by singleneedle pinyon and Utah Juniper (Pinus monophylla – Juniperus osteosperma). Restoration plans employing mechanical thinning or prescribed fire have primarily targeted expansion woodlands (i.e. woodlands not known to have existed prior to EuroAmerican settlement), but reference conditions for established (i.e. pre-settlement) woodlands is lacking. This study sought to fill that gap, first by evaluating evidence of historic fire severity, then by employing fire cycle techniques commonly used in analysis of boreal forests.

The Barrett Canyon watershed possesses a wide range of PJ stand structure and ages, along with fire scarred trees, that enabled a multi-century fire history study. Historical fire regime was dominated by infrequent, relatively small high severity fires. The apparent absence of small fires in established woodlands commencing with EuroAmerican settlement may warrant fire or fire surrogate treatments, but restoration plans should consider the strong influence of topography in fire cycle estimates. The fire cycle technique using an unbiased sampling scheme for stand ages is a workable alternative when past burn boundaries become indistinct with time. Fire scars, while not abundant, can form on the boundaries of past fires in PJ woodlands and greatly aid in interpretation of fire severity and extent.

Presentations:

Bauer, J.M. and P.J. Weisberg. 2006. Fire history and stand structure of a central Nevada pinyon-juniper woodland. 3rd International Fire Ecology and Management Congress, San Diego, CA. 11-14-06.

Bauer, J. and P.J. Weisberg. 2006. Fire history and stand structure of a central Nevada pinyon-juniper woodland. Nevada Wildland Fire Research and Outreach Conference, Desert Research Institute, Reno, NV. 4-17-06. (poster)

Publications:

Bauer, J.M. and P.J. Weisberg. Fire history of a central Nevada pinyon-juniper woodland. In preparation.

Bauer, J.M. 2006. Fire history and stand structure of a Central Nevada pinyon-juniper woodland. Masters Thesis. University of Nevada, Reno.

Py, C., J. Bauer, F. Biondi, and P.J. Weisberg. 2006. Radial growth responses of singleleaf pinyon (Pinus monophylla) to wildfire. Dendrochronologia 24: 39-46.

Summary Document:

Weisberg, P.J. and J .M. Bauer. Fire history and stand structure of a central Nevada pinyon-juniper woodland: Executive summary and final report . Unpublished report to the Bureau of Land Management, Nevada State Office.

Collaborators:

Dr. Robin Tausch, Supervisory Range Scientist, USDA Forest Service, Rocky Mountain Research Station, Reno

Dr. Franco Biondi, Associate Professor of Geography, University of Nevada - Reno, Department of Geography

Funding provided by: United States Department of the Interior, Bureau of Land Management (through the Great Basin Ecosystem Studies Unit )

Project duration: September, 2004 – January, 2007