Pacific Northwest Research Station

Disturbance Ecology and Management (DEM) Team

2008 Science Accomplishments

Encroaching juniper threaten sagebrush habitat

Juniper densities have increased since Euro-Americans first settled in Oregon. Credit: Mary Rowland

Sagebrush and other native shrublands in the Western United States are threatened by encroaching pinyon-juniper woodlands. In this study, scientists applied a pinyon-juniper risk model to the John Day province in central Oregon. They found that 140 years ago, prior to settlement by Euro-Americans, western juniper were scattered across the landscape with up to 7 trees per acre. Current densities of juniper younger than 140 years are much greater, ranging from 30 to 185 trees per acre, indicating most junipers in the study area were established post-settlement.

Canopy cover of sagebrush was lower in areas where the juniper canopy cover was most dense, a finding reported elsewhere. Low sagebrush and mountain big sagebrush communities in central Oregon may have the highest risk of future woodland encroachment. Juniper densities were greatest in the 1- to 3-foot-tall size class within these sites, suggesting relatively recent tree establishment but future growth and infilling.

Maps derived from this model will help land managers anticipate the magnitude and spatial patterns of potential sagebrush habitat loss from encroaching juniper woodlands.

Partners: USDA Forest Service Rocky Mountain Research Station, Remote Sensing Applications Center, Washington office, and Western Wildland Environmental Threat Assessment Center

To learn more, contact Mary Rowland at mrowland@fs.fed.us.

Surrogate species are an effective tool for conservation planning

How can the Forest Service and other federal agencies best address the conservation needs of hundreds of species of concern in land use planning? There are often too many species to consider each individually, even though all species of concern must be considered under federal laws and regulations.

Using surrogate species or groups of species as proxies for broader sets of species may be one way to address this dilemma. Scientists demonstrated this in the interior Columbia basin. An effective surrogate approach requires specific objectives, a regional geographic scale, explicit scientific criteria for selecting and linking surrogates to the larger set of species, tests of logic and consistency, identifying and demonstrating how knowledge gaps are addressed, and monitoring the effectiveness of management applications.

The surrogate species approach and guidelines are scientifically defensible and efficient, enabling managers to save substantial time and money. The Forest Service and Bureau of Land Management (BLM) are using these guidelines and approach in more than 50 administrative units in the interior Columbia basin. Also, the Forest Service has incorporated the approach and guidelines in its national planning direction, including proposed regulations to update guidelines for the National Forest Management Act.

Outcome: The U.S. Forest Service and the Bureau of Land Management adopt a surrogate species approach to conservation in the interior Columbia basin.

Partners: The Nature Conservancy, USDA Forest Service National Wildlife Ecology Program, USDI Bureau of Land Management

To learn more, contact Michael Wisdom at mwisdom@fs.fed.us.

Fuel treatments likely need to be repeated

In many fire-prone forests in the United States, changes over the last century have resulted in overstory structures, conifer densities, down woody structure, and fuel loads that deviate from those described historically. These conditions elevate the fire hazard. Fuel reduction treatments are one method for reducing fire hazard, but as scientists found, single applications of thinning and burning fuel-reduction treatments do not permanently mitigate the nearly 80 years of fire exclusion and fuel accumulation in low-elevation dry forests in northeastern Oregon.

Scientists used the Fuel Characteristics Classification System to construct a representative fuelbed for each study unit and then calculated three indices of fire potential as measures of the change in fire hazard resulting from treatments. Surface fire behavior, crown fire behavior, and fuels available for consumption returned to pretreatment levels within 6 years, indicating that repeated fuel reduction treatments may be needed to reduce the risk of uncharacteristically severe wildfires.

Outcome:The Joint Fire Science Program and the Wallowa-Whitman National Forest have used this study's results to synthesize the ecological effects of fuel reduction treatment.

Partners: Joint Fire Science Program, USDA Forest Service Wallowa-Whitman National Forest

To learn more, contact Andrew Youngblood at ayoungblood@fs.fed.us.

Tool: New snag and log sampling methods and software

Description: Snags and logs provide essential habitats for many forest animals, and land managers routinely monitor these structures in relation to other management goals. Accurate and efficient methods for sampling snags and logs have been integrated with software to facilitate evaluation of snag and log management and status in relation to other uses, including timber harvesting, firewood gathering, and other types of human access in the Northwestern United States.

Use: These new methods and software eliminate large sources of sampling bias present in past methods and increase sampling efficiency by more than 50 percent compared to past methods, none of which had software to facilitate sample design and data analysis. These methods, software, and results from their application are being used by national forests in eastern Oregon, eastern Washington, Idaho, and western Montana as part of forest planning, revisions, amendments, and environmental assessments and impact statements.

To learn more, contact Michael Wisdom at mwisdom@fs.fed.us.