Treesearch

Methods that integrate pre-, active-, and post-fire measurements to quantify fire effects across multiple spatial scales are needed to improve our understanding of ecological effects following fire and for informing natural resource management decisions that rely on post-fire growth and yield estimates. Given growth and yield modeling systems require tree level measurements to parameterize diameter and height distributions, effective datasets require both tree and stand level characterization. However, most stand-to-landscape scale fire effects studies use optical multispectral data (e.g.,...

Soil ammonia (NH3) emissions are seldom included in ecosystem nutrient budgets; however, they may represent substantial pathways for ecosystem nitrogen (N) loss, especially in arid regions where hydrologic N losses are comparatively small.To characterize how multiple factors affect soil NH3 emissions, we measured NH3 losses from 6 dryland sites along a gradient in soil pH, atmospheric N deposition, and rainfall.We also enriched soils with ammonium (NH4+), to determine whether N availability would limit emissions, and measured NH3 emissions with passive samplers in soil chambers following...

Many cold water-dependent aquatic organisms are experiencing habitat and population declines from increasing water temperatures. Identifying mechanisms which drive local and regional stream thermal regimes facilitates restoration at ecologically relevant scales. Stream temperatures vary spatially and temporally both within and among river basins. We developed a modeling process to identify statistical relationships between drivers of stream temperature and covariates representing landscape, climate, and management-related processes. The modeling process was tested in three study areas of...

Lodgepole pine forests are under threat due to wildfires of increasing severity and frequency coupled with tree mortality from insect outbreaks. Soil microbial communities, which drive biogeochemical cycles and partner in mycorrhizal symbiosis with lodgepole pines, play critical roles in the ability of these forests to survive and regenerate in the face of simultaneous global change threats. How soil microbial communities are influenced by fire severity and soil depth and how they recover over time in lodgepole pine forests with existing insect-driven mortality remains an open question....

Fire frequency and severity have increased in recent decades in the western United States, with direct implications for the quantity and composition of soil organic matter (SOM). While the effects of wildfire on soil carbon (C) and inorganic nitrogen (N) have been well studied, little is known about its impacts on soil organic N. Since organic N is the most abundant form of soil N in conifer forests and dominant source of plant N facilitated by symbiotic mycorrhizae and mineralization, better understanding of post-fire organic N chemistry will help address a critical gap in our understandin...

The mobilisation of potentially harmful chemical constituents in wildfire ash can be a major consequence of wildfires, posing widespread societal risks. Knowledge of wildfire ash chemical composition is crucial to anticipate and mitigate these risks. Here we present a comprehensive dataset on the chemical characteristics of a wide range of wildfire ashes (42 types and a total of 148 samples) from wildfires across the globe and examine their potential societal and environmental implications. An extensive review of studies analysing chemical composition in ash was also performed to complement...

Wildlife conservation necessitates understanding spatiotemporal drivers that facilitate disease outbreaks. Wildlife diseases are influenced by population and landscape level factors which affects host species’ persistence through time. Recurrent pneumonia outbreaks in bighorn sheep have impeded population recovery throughout the western US. Recovery efforts have included translocating animals, limiting contact with known reservoirs, removing infected individuals, and depopulating herds, but pneumonia outbreaks continue to negatively impact recovery. Here, our objective was to systematically...

1. Disturbance is a primary driver of exotic plant invasions, but why disturbance commonly favours exotics over natives is unresolved. 2. To address this question, we conducted the first biogeographic study of disturbance across multiple plant species. We experimentally disturbed grasslands and added seeds of 34 plant species to plots in their native range and in two introduced ranges that differed in invasibility (susceptibility to invasion) to evaluate recruitment while examining potential influences of resource availability, native community recovery from disturbance (resilience) and...

Climate change-triggered forest die-off is an increasing threat to global forests and carbon sequestration but remains extremely challenging to predict. Tree growth resilience metrics have been proposed as measurable proxies of tree susceptibility to mortality. However, it remains unclear whether tree growth resilience can improve predictions of stand-level mortality. Here, we use an extensive tree-ring dataset collected at ~3000 permanent forest inventory plots, spanning 13 dominant species across the US Mountain West, where forests have experienced strong drought and extensive die-off...

Restoration efforts are underway in dry conifer forests across the western United States to increase their resilience to wildfire and other disturbances. Because such treatments typically decrease overstory density and homogeneity, they can also drive changes in the understory plant community. Past studies of post-treatment changes in understories have found variable results over short time frames and across regions, highlighting the need to study longer-term, region-specific responses. We investigated whether mechanical restoration treatments benefited understory plants in dry conifer...