Treesearch

This report was designed to meet three broad goals: (1) evaluate wildfire hazard on Federal lands; (2) develop information useful in prioritizing where fuels treatments and mitigation measures might be proposed to address significant fire hazard and risk; and (3) develop risk-based performance measures to document the effectiveness of fire management programs. The research effort described in this report is designed to develop, from a strategic view, a first approximation of how fire likelihood and fire intensity influence risk to social, economic, and ecological values at the national...

The understory community is a critical component of many processes of forest ecosystems. Cover and biomass indices of shrubs and herbs of forested ecosystems of Northwestern United States are presented. Various forest data were recorded for 10,895 plots during a Current Vegetation Survey, over the National Forest lands of entire Pacific Northwest. No significant relationships between the percent canopy cover and understory percent cover and biomass indices were found for the 129 ecoclasses analyzed. Disturbance time and type, and the soil characteristics significantly influenced the shrub...

Sustainable forest management requires timely, detailed forest inventory data across large areas, which is difficult to obtain via traditional forest inventory techniques. This study evaluated k-nearest neighbor imputation models incorporating LiDAR data to predict tree-level inventory data (individual tree height, diameter at breast height, and species) across a 12 100 ha study area in northeastern Oregon, USA. The primary objective was to provide spatially explicit data to parameterize the Forest Vegetation Simulator, a tree-level forest growth model. The final imputation model utilized...

Due to the challenges faced by resource managers in maintaining post-fire ecosystem health, there is a need for methods to assess the ecological consequences of disturbances. This research examines an approach for assessing changes in post-fire vegetation dynamics for sites in Spain, Israel and the USA that burned in 1998, 1999 and 2002 respectively. Moderate Resolution Imaging Spectroradiometer satellite Normalized Difference Vegetation Index (NDVI) time-series data (2000-07) are used for all sites to characterise and track the seasonal and spatial changes in vegetation response. Post-fire...

We quantified changes in density of red squirrels (Tamiasciurus hudsonicus) in response to prescribed fire in mixed coniferous forests of Idaho and Washington, USA, using a Before-After-Control-Impact design. We found no evidence that low-severity prescribed fires affected density of red squirrels; we estimated the change in red squirrel densities due to prescribed fire as 20.15 squirrels/ha (95% CI 5 20.405­0.105). Squirrel density did, however, increase with increasing live tree density, shrub cover, and density of large downed logs, and varied across years and states. These results...

As society looks to our nation's forests as sources of energy, there is a risk of increased runoff and erosion. This report gives an overview of watershed processes, discusses the impacts of biomass removal on those processes, provides some guidelines to minimize adverse impacts, and describes an approach for estimating the effects of biomass removal on soil erosion.

Forest biomass thinnings, to promote forest health or for energy production, can potentially impact the soil resource by altering soil physical, chemical, and/or biological properties. The extent and degree of impacts within a harvest unit or across a watershed will subsequently determine if site or soil productivity is affected. Although the impacts of stand removal on soil properties in the western United States have been documented, much less is known on periodic removals of biomass by thinnings or other partial cutting practices. However, basic recommendations and findings derived from...

Indicator species concepts have a long history in conservation biology. Arguments in favor of these approaches generally stress expediency and assume efficacy. We tested the premise that the abundance patterns of one species can be used to infer those of other species. Our data consisted of 72,495 bird observations on 55 species across 1046 plots distributed across 30 sub basins. We analyzed abundance patterns at two spatial scales (plot and sub basin) and for empirical and a priori grouping. There were few significant indicator relationships at either scale or under either grouping rule,...

Every year, the four Federal wilderness management agencies - U.S. DOI Bureau of Land Management, Fish and Wildlife Service, National Park Service, and the USDA Forest Service - receive hundreds of proposals to conduct scientific studies within wilderness. There is no consistent and comprehensive framework for evaluating such proposals that accounts for the unique legal requirements of conducting such work inside wilderness, specifically the primary mandate of the 1964 Wilderness Act to "preserve wilderness character." This mandate demands that the standard for approving scientific...

Wildfire may pose serious threats to both direct (for example, heating, dissolved toxic gases) and indirect (for instance, post-fire floods, erosion, changing habitat), aquatic ecosystems (Dunham and others 2003; Gresswell 1999). There is, however, increasing recognition that major flood, erosion, and mass wasting events after fires can also be important to the formation of complex habitats that are beneficial in the long-term (Bisson and others 2003; Reeves and others 1995).