Treesearch

We present refinements for equations describing the temperature-wind covariance (v′ T′a ) reported by Massman and Lee (2002); namely, Eqs. (B.24), (B.25), and (B.28) in its Appendix B. The purpose of these equations is to express the wind covariance of air temperature (Ta) in terms of sonic temperature (Ts), as a sonic anemometer directly measures the latter rather than the former. Results of the derivations are summarized in Tables 1 and 2, and these refinements have been quantified using data from the Glacier Lakes Ecosystem Experiments Site (GLEES).

Heterobasidion annosum (Fr.) Bref. sensu lato (s.l.) is a dangerous forest pathogen causing root and butt rot disease in most conifers of the northern hemisphere. This pathogen is most widespread in the forests of Europe and North America. The economic impact on forestry related to tree mortality, reduction in timber yield, and wood rot is calculated in millions of dollars and euros. The genus Heterobasidion (Basidiomycota; Russulales) has been relatively recently separated into three genetically distinct groups (H. annosum, H. insulare and H. araucariae) comprising a total of 12 species...

In the western United States, pinyon-juniper woodlands have expanded by as much as sixfold among sagebrush landscapes since the late 19th century, with demonstrated negative impacts to the behav- ior, demography, and population dynamics of species that rely on intact sagebrush rangelands. Notably, greater sage-grouse (Centrocercus urophasianus) are unable to tolerate even low conifer cover, which can result in population declines and local extirpation, whereas removing expanding conifer cover has been demonstrated to increase sage grouse population growth rates and sagebrush obligate...

The relationship between bee community composition and habitat characteristics at local scales may inform management decisions and conservation strategies for species of conservation concern. Ecotones are transition zones between two adjacent habitats that can potentially support abundant and diverse bee communities by providing complementary habitat characteristics within the foraging distance of most bee species. In a forest-shrubland ecotone, we evaluated the relationships between multiple habitat characteristics and the taxonomic and functional diversity of bee communities. Early in...

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...