Treesearch

Work over the last decade has documented methods for estimating fluxes between streams and streambeds from time series of temperature at two depths in the streambed. We present substantial extension to the existing theory and practice of using temperature time series to estimate streambed water fluxes and thermal properties, including (1) a new explicit analytical solution to predict one-dimensional fluid velocity from amplitude and phase information; (2) an inverse function, also with explicit formulation; (3) methods to estimate fluid velocity from temperature measurements with unknown...

Lateral downslope flow in snow during snowmelt and rain-on-snow (ROS) events is a well-known phenomenon, yet its relevance to water redistribution at hillslope and catchment scales is not well understood. We used dye tracers, geophysical methods, and hydrometric measurements to describe the snow properties that promote lateral flow, assess the relative velocities of lateral flow in snow and soil, and estimate volumes of downslope flow. Results demonstrate that rain and melt water can travel tens of metres downslope along layers within the snowpack or at the snowpack base within tens of...

Deriving from original work under the National Cohesive Wildland Fire Management Strategy completed in 2011, this report summarizes the state of knowledge regarding the underlying causes and the role of wildfire prevention efforts on all major categories of wildfires, including findings from research that have sought to model wildfire occurrences over fine and broad spatial and temporal scales. The report also describes a conceptual model of wildfire ignitions, which is designed to provide a modeling framework for analysts who seek to better understand wildfire ignition processes or...

Estimates of survival of nearctic-neotropic migrants have broadened our understanding of life-history variation across taxa and latitudes. Despite the importance of assessing migrants' survival through all phases of their life-cycle, data from their tropical winter ranges are few. In this study we used 14 years of data on captured birds to quantify the influence of mass on the annual survival of the Prothonotary Warbler (Protonotaria citrea) in northeastern Costa Rica and compared our results to survival estimates generated from the breeding grounds. Furthermore, from estimates of populatio...

This report provides an overview of the public and private land and water resources of the United States. Described is use of natural and developed land as recreation resources with an emphasis on nature-based recreation. Also described is land protection through conservation organizations and public funding programs, with an emphasis on protecting private land through funding for purchase or for conservation easements. Outdoor recreation resources include land, water, snow and ice, scenery, developed sites, facilities, and user services. Protected land resources range from farm lands to...

Assessing the effect of thinning of overstorey trees and planting of native trees will be helpful to better understand the vegetation restoration. A stand conversion experiment was conducted in a 12-year-old Acacia auriculiformis plantation in 1996. Treatments were thinning and underplanting, underplanting, thinning, and control. Results showed that thinning enhanced the establishment and growth of underplanted and regenerated native seedlings. The thinning and underplanting treatment reduced soil organic matter, soil total nitrogen, soil bulk density and soil water content but increased...

Stream ecosystems are especially vulnerable to climate warming because most aquatic organisms are ectothermic and live in dendritic networks that are easily fragmented. Many bioclimatic models predict significant range contractions in stream biotas, but subsequent biological assessments have rarely been done to determine the accuracy of these predictions. Assessments are difficult because model predictions are either untestable or so imprecise that definitive answers may not be obtained within timespans relevant for effective conservation. Here, we develop the equations for calculating...

The eddy-covariance method often underestimates fluxes under stable, low-wind conditions at night when turbulence is not well developed. The most common approach to resolve the problem of nighttime flux underestimation is to identify and remove the deficit periods using friction-velocity (u∗) threshold filters (u∗Th). This study modifies an accepted method for u∗Th evaluation by incorporating change-point-detection techniques. The original and modified methods are evaluated at 38 sites as part of the North American Carbon Program (NACP) site-level synthesis. At most sites, the modified...

A current pine beetle infestation has caused extensive mortality of lodgepole pine (Pinus contorta) in forests of Colorado and Wyoming; it is part of an unprecedented multispecies beetle outbreak extending from Mexico to Canada. In United States and European watersheds, where atmospheric deposition of inorganic N is moderate to low (<10 kg�ha�y), disturbance of forests by timber harvest or violent storms causes an increase in stream nitrate concentration that typically is close to 400% of predisturbance concentrations. In contrast, no significant increase in streamwater nitrate concentratio...

There have been three comprehensive poplar bibliographies dating back to 1854 and the most recent contained literature published through 1988. Given that these bibliographies are outdated, the number of forestry/bioenergy related journals has increased dramatically (along with subsequent publications), and there have been profound advances in science (particularly in the areas of genetics and molecular biology) within the past two decades, development of the current bibliography was necessary. In addition to compiling the information, our objectives were to encourage publication in...