Treesearch

The Forest and Rangeland Renewable Resources Planning Act of 1974 (RPA) mandates a periodic assessment of the conditions and trends of the Nation's renewable resources on forests and rangelands. The RPA Assessment includes projections of resource conditions and trends 50 years into the future. The 2010 RPA Assessment used a set of future scenarios to provide a unifying framework for resources analyses. Those scenarios, and their associated assumptions about population change, economic growth, land use change, bioenergy, and climate change, are described in this document.

Hydrologic processes in the pinyon-juniper woodlands of the western region of the United States are variable because of the inherent interactions among the occurring precipitation regimes, geomorphological settings, and edaphic conditions that characterize the ecosystem. A wide range of past and present land-use practices further complicates comprehensive evaluations of these hydrologic processes. Heterogeneous vegetative covers make it even more difficult to generalize hydrologic processes and the effects of land management practices on the water balance. Nevertheless, estimates of...

Very little is known about how foliar moisture and chemistry change after a mountain pine beetle attack and even less is known about how these intrinsic foliar characteristics alter foliage ignitability. Here, we examine the fuel characteristics and ignition potential of Pinus contorta (lodgepole pine) foliage during the early stages of a mountain pine beetle attack. Foliar samples were taken periodically from multiple trees identified as green (healthy, unattacked), recently attacked, or red (dead). The fuel moisture content, chemical composition, and time to ignition of needles from each...

The 'energy imbalance problem' in micrometeorology arises because at most flux measurement sites the sum of eddy fluxes of sensible and latent heat (H + λE) is less than the available energy (A). Either eddy fluxes are underestimated or A is overestimated. Reasons for the imbalance are: (1) a failure to satisfy the fundamental assumption of one-dimensional transport that is necessary for measurements on a single tower to represent spatially-averaged fluxes to/from the underlying surface, and (2) measurement errors in eddy fluxes, net radiation and changes in energy storage in soils, air...

Riparian forests of the American Southwest are especially prone to changes in composition and structure due to natural and anthropogenic factors. To determine how breeding mourning doves (Zenaida macroura) respond to these changes, we examined nest site use and nest survival in control plots, fuel reduction plots before and after mechanical thinning, and post-wildfire sites. The greatest number of nests (50%) were located in post-wildfire sites where resprouted vegetation and woody debris provided numerous nest sites in the understory. We found fewer nests in post-treatment fuel reduction...

Tourism is a spatial practice involving two seemingly opposing geographic processes. One is aptly captured by McHugh's (2006b) phrase "nomads of desire" referring to the ways amenity-seeking mobilities and travel are deeply rooted in the Western imagination. The other is succinctly expressed in Lippard's (1997) book titled "The Lure of the Local" describing the enigmatic and increasingly multicentric nature of place affinities and attachments and sense of home and community. Within the social sciences, place and mobility have long been treated as distinct topics with their own distinct...

Container longleaf pine (Pinus palustris) seedlings often survive and grow better after outplanting than bareroot seedlings. Because of this, most longleaf pine are now produced in containers. Little is known about nursery fertilization effects on the quality of container longleaf pine seedlings and how that influences outplanting performance. We compared various fertilization rates (0.5, 1, 2, 3, or 4 mg nitrogen (N) per week for 20 weeks) for two crops (2004 and 2005) of container longleaf pine, grown inside a fullycontrolled greenhouse (2004 and 2005) or in an outdoor compound (2005)....

Sagebrush-steppe ecosystems are one of the most threatened ecosystems in North America due to woodland expansion, wildfire, and exotic annual grass invasion. Some scientists and policy makers have suggested that woodland expansion will lead to increased carbon (C) storage on the landscape. To assess this potential we used data collected from a Joint Fire Sciences Program demonstration area to develop a Microsoft Excel based biomass, carbon, and nitrogen (N) spreadsheet model. The model uses input for tree cover, soil chemistry, soil physical properties, and vegetation chemistry to estimate...

Indices that rate the vulnerability of species to climate change in a given area are increasingly used to inform conservation and climate change adaptation strategies. These species vulnerability indices (SVI) are not commonly associated with landscape features that may affect local-scale vulnerability. To do so would increase their utility by allowing managers to examine how the distributions of vulnerable species coincide with environmental features such as topography and land use, and to detect landscape-scale patterns of vulnerability across species. In this study we evaluated 15...

Fusarium commune can cause damping-off and root rot of conifer seedlings in forest nurseries, and this pathogen has been previously reported from Oregon, Idaho, and Washington, USA. We collected Fusarium isolates from additional nurseries in the midwestern and western USA to more fully determine occurrence of this pathogen. We used DNA sequences of the mitochondrial small subunit gene to identify F. commune. In addition to confirming the occurrence of F. commune in Oregon, Idaho, and Washington, USA, we also discovered that F. commune is even more widespread with this first report of F....