Treesearch

Substantial genetic variation in development time is known to exist among mountain pine beetle (Dendroctonus ponderosae Hopkins) populations across the western United States. The effect of this variation on geographic patterns in voltinism (generation time) and thermal requirements to produce specific voltinism pathways have not been investigated. The influence of voltinism on fitness traits, body size, and sex ratio is also unclear. We monitored mountain pine beetle voltinism, adult body size, sex ratio, and air temperatures at sites across latitudinal and elevational gradients in the...

Entomologists and silviculturists have long recommended management of stand basal area and/or mean tree diameter to mitigate the risk of mountain pine beetle (MPB) (Dendroctonus ponderosae Hopkins) outbreaks while simultaneously reducing wildfire risk. In recent decades, however, wildfire suppression and reduced harvests in western North America have created a forest landscape that is densely stocked and increasingly susceptible to bark beetle infestations, especially as the climate becomes warmer and drier. We examine the various MPB treatment options available to land managers, including...

The Future Forest Webinar Series facilitated dialogue between scientists and managers about the challenges and opportunities created by the mountain pine beetle (MPB) epidemic. The series consisted of six webinar facilitated by the USFS Rocky Mountain Research Station, the Northern and Rocky Mountain Regions, and the Colorado Forest Restoration Institute. The series ran from October 2011 to December 2012 and covered a variety of topics related to the MPB epidemic: potential fire risk and behavior, current and future vegetation conditions, wildlife habitats and populations, social and...

Wildfire activity in the United States incurs substantial costs and losses, and presents challenges to federal, state, tribal and local agencies that have responsibility for wildfire management. Beyond the potential socioeconomic and ecological losses, and the monetary costs to taxpayers due to suppression, wildfire management is a dangerous occupation. Aviation resources, in particular large airtankers, currently play a critical role in wildfire management, and account for a relatively large share of both suppression expenditure and firefighting fatalities. A recent airtanker modernisation...

Recent fire seasons in the western United States are some of the most damaging and costly on record. Wildfires in the wildlandurban interface on the Colorado Front Range, resulting in thousands of homes burned and civilian fatalities, although devastating, are not without historical reference. These fires are consistent with the characteristics of large, damaging, interface fires that threaten communities across much of the western United States. Wildfires are inevitable, but the destruction of homes, ecosystems, and lives is not. We propose the principles of risk analysis to provide land...

Clean water is essential for ecosystem processes and for the maintenance of human populations. However, fresh water accounts for less than three percent of the world’s total water volume. Numerous anthropogenic and natural processes impact the quality and quantity of the available resource. The value of high-quality water will likely increase as threats to water resources expand and human demands increase. In the United States, public lands such as forests and grasslands often contain watersheds that have been minimally modified by human disturbances. Wilderness areas in particular often...

Collection of non-urban ambient ozone data at regional or larger scales (for example, Peake and Fong 1990; Bytnerowicz et al. 2004) is cost- and labor-intensive. Collection efforts are often further complicated by difficulty of access to data collection sites, the need for climate-controlled facilities to house instrumentation, and a requirement for a connection to utility-grade (grid) power. Regional ozone is more often studied via modeling (for example, Kumar et al. 1994). Although nitrite-based passive samplers (Koutrakis et al. 1993; Vardoulakis et al. 2009) may be used to estimate...

Valley confinement is an important landscape characteristic linked to aquatic habitat, riparian diversity, and geomorphic processes. This report describes a GIS program called the Valley Confinement Algorithm (VCA), which identifies unconfined valleys in montane landscapes. The algorithm uses nationally available digital elevation models (DEMs) at 10-30 m resolution to generate results at subbasin scales (8 digit hydrologic unit). User-defined parameters allow results to be tailored to specific applications and landscapes. Field data were sampled to verify geomorphic characteristics of...

Estimating the thermal response of streams to a warming climate is important for prioritizing native fish conservation efforts. While there are plentiful estimates of air temperature responses to climate change, the sensitivity of streams, particularly small headwater streams, to warming temperatures is less well understood. A substantial body of literature correlates subannual scale temperature variations in air and stream temperatures driven by annual cycles in solar angle; however, these may be a low-precision proxy for climate change driven changes in the stream energy balance. We...

Wolverines were greatly reduced in number and possibly extirpated from the contiguous United States (U.S.) by the early 1900s. Wolverines currently occupy much of their historical range in Washington, Idaho, Montana, and Wyoming, but are absent from Utah and only single individuals are known to occur in California and Colorado. In response, the translocation of wolverines to California and Colorado is being considered. If wolverines are to be reintroduced, managers must identify appropriate source populations based on the genetic affinities of historical and modern wolverine populations....