Treesearch

Recent bark beetle outbreaks in North America and Europe have impacted forested landscapes and the provisioning of critical ecosystem services. The scale and intensity of many recent outbreaks are widely believed to be unprecedented. The effects of bark beetle outbreaks on ecosystems are often measured in terms of area affected, host tree mortality rates, and alterations to forest structure and composition. Impacts to human systems focus on changes in property valuation, infrastructure damage from falling trees, landscape aesthetics, and the quality and quantity of timber and water...

Wildfire can damage headwater wetlands, yet the value of post-fire restoration treatments in channels has been contested. Staff from the White Mountain Apache Tribe, students from the local Cibecue Community School, and researchers from the U.S. Forest Service collaboratively recorded channel responses over 13 years at two headwater wetlands lying within watersheds that were severely burned by the Rodeo-Chediski wildfire (Arizona, U.S.) in 2002. One site, Turkey Spring, was left largely untreated for 11 years following the fire, while the second site, Swamp Spring, was treated in 2005 by...

We propose an economic analysis using utility and productivity, and efficiency theories to provide fire managers a decision support tool to determine the most efficient fire management programs levels. By incorporating managers’ accumulated fire suppression experiences (capitalized experience) in the analysis we help fire managers determine fire suppression productivity and efficient budget allocation. Furthermore, monitoring of the management index (MI) helps identify operational deficiencies in the different districts where the analysis is applied. This is so because internally the area...

In a Mediterranean climate where much of the precipitation falls during winter, snowpacks serve as the primary source of dry season runoff. Increased warming has led to significant changes in hydrology of the western United States. An important question in this context is how to best manage forested catchments for water and other ecosystem services? Answering this basic question requires detailed understanding of hydro-logic functioning of these catchments. Here, we depict the differences in hydrologic response of 10 catchments. Size of the study catchments ranges from 50 to 475 ha, and...

An emerging hypothesis in fire ecology is that pyrodiversity increases species diversity.We test whether pyrodiversity—defined as the standard deviation of fire severity—increases avian biodiversity at two spatial scales, and whether and how this relationship may change in the decade following fire. We use a dynamic Bayesian community model applied to a multi-year dataset of bird surveys at 1106 points sampled across 97 fires in montane California. Our results provide strong support for a positive relationship between pyrodiversity and bird diversity. This relationship interacts with time...

The use of remote sensing in ecosystem management has transformed how land managers, practitioners, and policymakers evaluate ecosystem loss, gain, and change at multiple spatial and temporal scales. Less developed is the use of these spatial tools for planning, implementing, and evaluating ecosystem restoration projects and especially so in multifunctional landscapes. We use a case study approach in a multistakeholder tropical dryland restoration project to highlight the potential of remotely sensed products to quantitatively and economically guide often conflicting restoration priorities...

Conspecific density may contribute to patterns of species assembly through negative density dependence (NDD) as predicted by the Janzen-Connell hypothesis, or through facilitation (positive density dependence; PDD). Conspecific density effects are expected to be more negative in darker and wetter environments due to higher pathogen abundance and more positive in stressful, especially dry, environments (stress-gradient hypothesis). For NDD to contribute to maintaining diversity, it should be apparent at the community-wide scale as a negative correlation between seedling recruitment, growth...

Understanding of migration in small bats has been constrained by limitations of techniques that were labor-intensive, provided coarse levels of resolution, or were limited to population-level inferences. Knowledge of movements and behaviors of individual bats have been unknowable because of limitations in size of tracking devices and methods to attach them for long periods. We used sutures to attach miniature global positioning system (GPS) tags and data loggers that recorded light levels, activity, and temperature to male hoary bats (Lasiurus cinereus). Results from recovered GPS tags...

Information on urban tree growth underpins models used to calculate the effects of trees on the environment and human well-being. Maximum tree size and other growth data are used by urban forest managers, landscape architects, and planners to select trees most suitable to the amount of growing space, thereby reducing costly future conflicts between trees and infrastructure. Growth data are used to examine relationships between growth and influencing factors such as site conditions and stewardship practices. Despite the importance of tree growth data to the science and practice of urban...

Wildfires are a common occurrence in California shrublands, maintaining ecosystem functions with the regeneration of key shrub species. The Cedar Fire of 2003 in southern California was unique in that a portion of it burned with wildfire accelerated by dry, strong northeasterly Santa Ana winds that later subsided, while the remaining area burned under an onshore, westerly wind of lower velocity and higher humidity. These nearby areas, having similar terrain, fuel type, and environments, burned under these different conditions. Our goal is to understand the connection between vegetation...