Treesearch

Governments and institutions across the globe are conducting vulnerability assessments and developing adaptation plans to confront rapidly changing climatic conditions. Interrelated priorities, including the conservation of biodiversity, ecological restoration, sustainable development, and social justice often underlie these efforts. We collaborated with colleagues in an effort to help guide vulnerability assessment and adaptation (VAA) generally in Southeast Asia and specifically in the watershed of the Sirindhorn International Environmental Park (SIEP) in Phetchaburi Province, Thailand....

Natural resources are often subject to state uncertainty: resource abundance is not known with certainty, but can be measured. Measurements are typically imperfect and costly to obtain. The decision of whether to invest in resource measurement may be influenced by other state variables, for example a resource commodity price. We introduce a mixed-observability model of optimal forest management featuring a partially-observable forest resource and perfectly-observable stochastic price. The decision maker optimizes the expected net present value of forest returns by choosing when to measure...

Trace gas, particulate matter and deposition data collected in the Athabasca Oil Sands Region (AOSR) from 2000 to 2017 were evaluated as part of a broad scientific programmatic review. Results showed significant spatial patterns and temporal trends across the region. Concentrations of reactive gases were highest near the center of surface oil sands production operations and decreased towards the edges of the monitoring domain by factors of 8, 20, 4 and 3 for SO2, NO2, HNO3and NH3, respectively. 18 of 30 sites showed statistically significant (p< 0.05) negative trends in SO2concentrations...

We measured forest-floor accumulation in ponderosa pine forests of central Oregon and asked whether selected ecological functions of the organic layer were altered by thinning and repeated burning. Experimental treatments included three thinning methods applied in 1989 (stem only, whole tree, no thin—control) in factorial combination with prescribed burning (spring 1991 and repeated in 2002; no burn—control). Forest-floor depth and mass were measured every 4–6 years from 1991 to 2015. Without fire, there was little temporal change in depth or mass for thinned (270 trees ha−1) and control...

Prescribed fire is a vital tool for mitigating wildfire hazard and restoring ecosystems in many western North American forest types. However, there can be considerable variability in fuel consumption from prescribed burns, which affects both hazard mitigation and emissions. In the present study, data from replicated, repeat-entry burns following a period of 100+ years of fire exclusion were used to provide a detailed quantification of fuel consumption as it varies by fuel type, size class, stand and prescribed burn number (first, second or third). Using model selection on a series of...

Managed wildfire is an increasingly relevant management option to restore variability in vegetation structure within fire-suppressed montane forests in western North America. Managed wildfire often reduces tree cover and density, potentially leading to increases in soil moisture availability, water storage in soils and groundwater, and streamflow. However, the potential hydrologic impacts of managed wildfire in montane watersheds remain uncertain and are likely context dependent. Here, we characterize the response of vegetation and soil moisture to 47 years (1971–2018) of managed wildfire...

Understanding forest regeneration in the wake of large-scale wildfire events is critically important because these disturbances are expected to occur more frequently given future climate projections. While the impacts of individual management prescriptions on prevention, mitigation, and response to severe fire events have been studied, the influence of property ownership on their implementation and success has received less attention. The objective of this study was to compare how the management practices of two common US forestland owners- public (U.S. Forest Service) and a private forest...

Forests are the largest terrestrial carbon stock, and disturbance regimes can have large effects on the structure and function of forests. Many dry temperate forests in the western United States are adapted to a regime of frequent, low‐to‐moderate severity fire. The disruption of this disturbance regime over the last century has shifted forest conditions, making them more susceptible to high‐severity fire. Fuel treatments have been shown to effectively reduce wildfire hazard, often with co‐benefits to ecological values. However, the effects of fuel treatments on forest carbon are complex,...

Multiple introductions in California of Phytophthora cinnamomi are severely threatening its native ecosystems. However, little is known about the consequences of outbreaks caused by different genotypes on endemic hosts. Virulence of 10 genotypes representative of the California and worldwide genetic variability of P. cinnamomi was studied on roots and stems of four native California plant hosts. Hosts differed in type of response and susceptibility level, and individual pathogen genotypes differed in virulence. Pathogen variability was clear when testing hosts of moderate susceptibility...

Bark beetles are important disturbance agents in coniferous forests, and spruce beetle, Dendroctonus rufipennis(Kirby) (Coleoptera: Curculionidae), is one of the more notable species causing landscape-level tree mortality in western North America. We evaluated the efficacy of bole injections of emamectin benzoate (TREE-äge®; Arborjet Inc., Woburn, MA) alone and combined with propiconazole (Alamo®; Syngenta Crop Protection Inc., Wilmington, DE) for protecting Engelmann spruce, Picea engelmanniiParry ex Engelmann (Pinales: Pinaceae), from mortality attributed to colonization byD. rufipennis....