Treesearch

Across the higher mountains of the western United States and Canada and in northern Mexico, there are six species of pines informally referred to by researchers and managers as the "high elevation five-needle white pines" (e.g., Tomback et al., 2011; Keane et al., 2011; H5II High Elevation Five Needle Pine Research Conference (high-five pines.org). These pines are related at the subgenus level (Family Pinaceae, Genus Pinus, Subgenus Strobus) but classified within two different taxonomic pine sections, reflecting their different evolutionary affinities: Section Quinquefoliae-whitebark...

Restoration of an alluvial wet-meadow system was conducted in the late 1990s to reestablish hydraulic interactions between the river, floodplain, and groundwater to support aquatic–riparian ecosystem function. A single-discharge approach sized the bankfull channel dimensions to the effective discharge (Qe) and three degrees of channel widening relative to the Qe design were explored to identify which design attained dynamic equilibrium in the shortest time. The three experimental channel designs were implemented with bankfull widths of 96%, 157%, and 191%, respectively, of the Qe geometry....

Wildfire is a complex problem because of the diverse mix of actors and landowners involved, uncertainty about outcomes and future conditions, and unavoidable trade-offs that require ongoing negotiation. In this perspective, we argue that addressing the complex challenge of wildfire requires governance approaches designed to fit the nature of the wildfire problem. For instance, while wildfire is often described as a cross-boundary problem, understanding wildfire risk as transboundary highlights important political and institutional challenges that complicate collaboration across jurisdiction...

Remotely piloted aircraft systems (RPAS) are providing fresh perspectives for the remote sensing of fire. One opportunity is mapping tree crown scorch following fires, which can support science and management. This proof-of-concept shows that crown scorch is distinguishable from uninjured canopy in point clouds derived from low-cost RGB and calibrated RGB-NIR cameras at fine resolutions (centimeter level). The Normalized Difference Vegetation Index (NDVI) provided the most discriminatory spectral data, but a low-cost RGB camera provided useful data as well. Scorch heights from the point...

Increased ecological disturbances, species invasions, and climate change are creating severe conservation problems for several plant species that are widespread and foundational. Understanding the genetic diversity of these species and how it relates to adaptation to these stressors are necessary for guiding conservation and restoration efforts. This need is particularly acute for big sagebrush (Artemisia tridentata; Asteraceae), which was once the dominant shrub over 1,000,000 km2 in western North America but has since retracted by half and thus has become the target of one of the largest...

Juvenile tree survival will increasingly shape the persistence of ponderosa pine forests in the western United States. In contrast to severe pulse disturbances that induce widespread adult and juvenile tree mortality, moderate periods of low rainfall and warm temperatures may reduce forest persistence by killing juvenile trees at the seedling stage. Intensification of these periods in a changing climate could therefore increasingly restrict both natural regeneration and artificial regeneration of planted seedlings. We conducted a controlled field experiment at a single site in the Front...

Western juniper (Juniperus occidentalis Hook.) woodlands have persisted for millennia in semiarid parts of the northern Great Basin, USA, providing critical habitat for plant and animal species. Historical records suggest that the establishment of western juniper is strongly associated with regional climatic variability. For example, the abundance of western juniper pollen and macrofossils measured in lake sediment cores increased rapidly in the mid- 1500s, concurrent with a regional increase in winter precipitation. However, little is known about how climatic factors interact with...

Wildlife dispersal directly influences population expansion patterns, and may have indirect effects on the spread of wildlife diseases. Despite its importance to conservation, little is known about dispersal for several species. Dispersal processes in expanding wolf (Canis lupus) populations in Europe is not well documented. Documenting the natural dispersal pattern of the expanding wolf population in the Alps might help understanding the overall population dynamics and identifying diseases that might be connected with the process. We documented 55 natural dispersal events of the expanding...

Two new climate-based root disease models have been developed for Region 1. One model provides estimates of climatic suitability for root disease and the other provides estimates of potential root disease severity. These models were developed using root disease presence and severity data collected on Forest Inventory and Analysis (FIA) plots and incorporate climatic and biophysical variables to estimate the spatial distributions of suitable climate for root disease and potential severity where root disease may occur. The model outputs are assigned to VMap polygons via ancillary tables....

Recent intense fire seasons in Australia, Borneo, South America, Africa, Siberia, and western North America have displaced large numbers of people, burned tens of millions of hectares, and generated societal urgency to address the wildfire problem (Bowman et al. 2020). Nearly all terrestrial ecosystems, however, burn with some degree of regularity, timing, and intensity; fire is a natural process. Wildfires are strongly influenced by climate and weather, which in turn shape the availability and flammability of fuels (Abatzoglou and Williams 2016). Yet rapid climate change is interacting...