Treesearch

Populus trichocarpa Torr. and Gray (black cottonwood) is an economically and ecologically important tree species native to western North America. It serves as a model tree species in biology and genetics due to its relatively small genome size, rapid growth, and early reproductive maturity (Jansson and Douglas 2007). Black cottonwood is susceptible to root rot caused by at least one species of Armillaria (Raabe 1962), a globally distributed genus that exhibits diverse ecological behaviors (Klopfenstein et al. 2017) and infects numerous woody plant species (Raabe 1962). However, several...

The fungus Elytroderma deformans causes a serious needle disease of pines in western North America and is considered the most important needle disease of ponderosa pine in Montana. While important, there has been limited evaluation of pre-commercial thinning or other treatments on disease incidence. Our study assessed the efficacy of various silvicultural treatments to reduce impacts from Elytroderma disease within monitoring plots that were established in 2004 and surveyed until 2014. Treatments were randomly assigned through incomplete block design to: (1) thin to 3.7 x 3.7 m spacing;...

The Colorado River is among the most extensively managed river systems in the world. The river’s headwaters are within the Rocky Mountains in the United States. From there, it flows through the arid lands of the Colorado Plateau and the Basin-and-Range to its delta in northwestern Mexico. Here, the river is the only significant water supply in an otherwise starkly arid landscape and has long been called “America’s Nile.” It provides a critical water supply for nearly four million acres of irrigated land, municipal supplies for 30 million people located within and outside the basin, and...

Using a threshold public good experiment, we examine how varying degrees of inequality in resources and differences in risk of loss among players affect the success of group efforts to avoid a common loss. We find that when the poor face greater risk than the rich, contributions and success in reaching the threshold decrease with increasing inequality in funds available. This occurs not because the poor do not make a greater effort when they face higher risk but rather because the rich, who control most of the resources, tend to lower their contributions when they face the lower risk, and...

Phenology is the study of recurring plant and animal life-cycle stages which can be observed across spatial and temporal scales that span orders of magnitude (e.g., organisms to landscapes). The variety of scales at which phenological processes operate is reflected in the range of methods for collecting phenologically relevant data, and the programs focused on these collections. Consideration of the scale at which phenological observations are made, and the platform used for observation, is critical for the interpretation of phenological data and the application of these data to both...

Wildfire risks and losses have increased over the last 100 years, associated with population expansion, land use and management practices, and global climate change. While there have been extensive efforts at modeling the probability and severity of wildfires, there have been fewer efforts to examine causal linkages from wildfires to impacts on ecological receptors and critical habitats. Bayesian networks are probabilistic tools for graphing and evaluating causal knowledge and uncertainties in complex systems that have seen only limited application to the quantitative assessment of...

Recent wildland fire disasters have attracted interest from a variety of disciplines seeking to reduce impacts of fire on people and natural resources. Architecture, insurance and reinsurance, city and county government, and engineering sectors have contributed ideas to mitigate or avoid damage during wildland fires. This paper examines the modern wildland fire system in terms of the historical context for wildland fire, primarily in the US, and discusses some of the characteristics of this system and its human culture that affect the potential impact of innovations and engineering...

Background: Proteins with nucleotide binding site (NBS) and leucine-rich repeat (LRR) domains (NLR) make up one of most important resistance (R) families for plants to resist attacks from various pathogens and pests. The available transcriptomes of limber pine (Pinus flexilis) allow us to characterize NLR genes and related resistance gene analogs (RGAs) in host resistance against Cronartium ribicola, the causal fungal pathogen of white pine blister rust (WPBR) on five-needle pines throughout the world. We previously mapped a limber pine major gene locus (Cr4) that confers complete resistanc...

Fungal and mite associates may drive changes in bark beetle populations, and mechanisms constraining beetle irruptions may be hidden in endemic populations. We characterized common fungi of endemic-level Jeffrey pine beetle (JPB) in western USA and analyzed their dissemination by JPB (maxillae and fecal pellet) and fungivorous mites to identify if endogenous regulation drove the population. We hypothesized that: (1) as in near-endemic mountain pine beetle populations, JPB’s mutualistic fungus would either be less abundant in endemic than in non-endemic populations or that another fungus...

For over 20 years, forest fuel reduction has been the dominant management action in western US forests. These same actions have also been associated with the restoration of highly altered frequent-fire forests. Perhaps the vital element in the compatibility of these treatments is that both need to incorporate the salient characteristics that frequent fire produced - variability in vegetation structure and composition across landscapes and the inability to support large patches of high-severity fire. These characteristics can be achieved with both fire and mechanical treatments. The...