Treesearch

Phenology can be linked to individual fitness, particularly in strongly seasonal environments where the timing of events has important consequences for growth, condition, and survival. We studied the phenology of coho salmon (Oncorhynchus kisutch) hatching and emergence in streams with contrasting thermal variability but in close geographic proximity. Following emergence, we tracked body sizes of cohorts of young-of-year fish until the end of the growing season. Hatch and emergence occurred at the same time among streams with marked variability in thermal regimes. We demonstrate that this...

At the ecosystem scale, water-use efficiency (WUE) is defined broadly as the ratio of carbon assimilated to water evaporated by an ecosystem. WUE is an important aspect of carbon and water cycling and has been used to assess forest ecosystem responses to climate change and rising atmospheric CO2 concentrations. This study investigates the influence of meteorological and radiation variables on forest WUE by analyzing an 18 year (1998–2015) half-hourly time series of carbon and water fluxes measured with the eddy covariance technique in an old-growth conifer forest in the Pacific Northwest,...

Natural resource advisors operate at a natural resource-climate nexus that presents opportunity for utilization of regionally relevant climate science and tools to support climate smart decision making among land managers. This opportunity, however, may be underutilized. In thousands of county offices across the country, USDA field staff with the Natural Resources Conservation Service (NRCS) and Farm Service Agency (FSA) interface with farmers on a daily basis to provide conservation technical assistance, farm loans, and disaster recovery assistance. In this study, we conducted a survey of...

The American West exists in the popular imagination as a distinct region, and policies and politics often suggest that both the challenges and the opportunities for land management and human well-being across the region are relatively homogeneous. In this paper, we argue that there are key characteristics that define the West as a social-ecological region, and also that there are myriad social-ecological systems (SESs) within the region that require diverse and dynamic approaches to managing change over time. We first conceptualize aridity, topography, and a unique political economy of...

Climate change is altering the conditions for tree recruitment, growth, and survival, and impacting forest community composition. Across southeast Alaska, USA, and British Columbia, Canada, Callitropsis nootkatensis (Alaska yellow‐cedar) is experiencing extensive climate change‐induced canopy mortality due to fine‐root death during soil freezing events following warmer winters and the loss of insulating snowpack. Here, we examine the effects of ongoing, climate‐driven canopy mortality on forest community composition and identify potential shifts in stand trajectories due to the loss of a...

Disturbance is an integral component of forest ecosystems. Therefore, contemporary changes to the frequency and severity of disturbances in forests may have lasting ecological consequences. In recent decades, widespread mountain pine beetle (MPB; Dendroctonus ponderosae) outbreaks have contributed more to total tree mortality than other disturbances such as wildfire. Past studies have used a broad range of measurements to evaluate the local effects of beetle outbreaks on birds (e.g., dead trees per acre versus percent mortality) and this has led to some challenges and inconsistencies in...

The vast majority of measurements in the field of plant hydraulics have been on small‐diameter branches from woody species. These measurements have provided considerable insight into plant functioning, but our understanding of plant physiology and ecology would benefit from a broader view, because branch hydraulic properties are influenced by many factors. Here, we discuss the influence that other components of the hydraulic network have on branch vulnerability to embolism propagation. We also modelled the impact of changes in the ratio of root‐to‐leaf areas and soil texture on vulnerabilit...

Plant gas exchange systems are widely used to study leaf physiological processes and properties such as stomatal function and the maximum carboxylation rate of Rubisco. Increasingly, these systems are used to assess how leaf gas exchange varies with temperature in order to better understand how rising temperature will impact plant function. Examples of such studies include variation in optimal temperatures of photosynthesis as a function of species and growth environment, and respiratory acclimation to higher temperatures. Leaf thermoregulation leading to homeothermy has been reported...

In order to increase the pace and scale of managing forests to reduce wildfire risk in the western U.S., federal agencies have adopted policies that promote an all lands management (ALM) approach, which extends management actions across jurisdictional boundaries. To better implement such policies, ALM approaches require new governance systems that overcome barriers found in existing systems, which typically address jurisdictions separately. Polycentric governance systems, characterized by multiple and diverse actors at different scales operating in coordination with one another under an...

Fuel reduction treatments are designed to meet multiple management objectives, resulting in unique vegetation structures that do not conform to standard classifications and vary considerably over space and time. We evaluated how different post-treatment vegetation structures relate to patterns in wildfire severity. To reconstruct both untreated and treated pre-fire forest structure, we used post-fire stand data measured at three different fuel treatment units burned by the 2011 Wallow Fire (Arizona). We describe (1) how forest structure differs among the treatment units, both in the...