Treesearch

Many fungi in the Ophiostomatales are vectored by bark beetles that introduce these fungi directly into their tree hosts. Most of these fungal associates have little effect on their hosts, but some can cause serious diseases. One such fungus, Leptographium wageneri, causes an economically and ecologically important tree disease known as black stain root disease (BSRD). For this study, 159 full genome sequences of L. wageneri were analyzed using a population genomics approach to investigate the epidemiology, dispersal capabilities, and reproductive biology of this fungus. Analyses were...

Population growth rates in Sub-Saharan East Africa are among the highest in the world, creating increasing pressure for land cover conversion. To date, however, there has been no comprehensive assessment of regional land cover change, and most long-term trends have not yet been quantified. Using a designed sample of satellite-based observations of historical land cover change, we estimate the areas and trends in nine land cover classes from 1998 to 2017 in Ethiopia, Kenya, Uganda, Malawi, Rwanda, Tanzania, and Zambia. Our analysis found an 18,154,000 (±1,580,000) ha, or 34.8%, increase in...

Climate may separate grasslands from surrounding forests and shrublands, but an alternative option is that grasslands are suitable for trees except in the presence of frequent fires, which are spread great distances by strong winds. To develop a ruleset that demarcated the central North American grasslands, I modeled grasslands using precipitation and its coefficient of variation, ratio of potential evapotranspiration to precipitation, climatic moisture index, July vapor pressure, and wind speed (i.e., a fire indicator) during 5000 (4900-5100) years before present, 1600-1699, 1800-1849,...

Wildland fire is a disturbance that shapes frequent-fire forest ecosystems and the life-histories of wildlife species that inhabit them. The California spotted owl (Strix occidentalis occidentalis) is an iconic old-forest species that evolved under a frequent-fire regime in western North America. While recent studies have focused on owl response to large, severe fire events, relatively little is known about how owls might respond to prescribed fires and wildfires managed for resource benefit. Therefore, understanding how owls use landscapes that are managed using fire may offer insight...

Forest sustainability is explicitly tied to soil health, which has been defined as "the capacity of a soil to function within ecosystem boundaries to sustain biological productivity, maintain environmental quality, and promote plant and animal health" (Doran et al., 1996; Sigua, 2018). This definition includes the ability of soil to function effectively as a component of healthy forests (Schoenholtz et al., 2000) and is linked to the soils ability to support physical, chemical, and biological properties while also suppressing plant pathogens (van Bruggen and Semenov, 2000). In broad terms,...

The USDA Forest Service Rocky Mountain Research Station (RMRS) and Intermountain Region (R4) are modeling an approach to how National Forest System management and science can work together in meaningful ways with tangible results. The R4-RMRS Science Partner Program actively cultivates relationships between research scientists and land managers to co-produce new knowledge and land management approaches. When scientists and managers develop solutions together, we strengthen the agency’s ability to address the complex challenges facing our forests, grasslands, and the communities that depend...

The encroachment of pinyon-juniper woodlands into sagebrush habitat in the Great Basin Ecoregion of the western USA, represents a potential source of habitat degradation for sagebrush-associated wildlife species. To restore sagebrush habitat, managers are conducting large-scale conifer removal efforts within the Great Basin, particularly within Greater Sage-Grouse (Centrocercus urophasianus) priority areas for conservation. Such largescale habitat modification efforts may result in unintended ecological trade-offs for wildlife. To investigate these trade-offs, we used community science...

In natural environments, plants develop adaptive mechanisms at the cellular and molecular levels to cope with many external factors, e.g., insects and soil pathogens. We studied physiological stress induced by different levels of foliage removal (defoliation 30% and 60%) and by infection of root rot pathogen Phytophthora plurivora on the common Polish tree species, Betula pendula, grown in an open greenhouse. This study showed that P. plurivora damaged the root system which negatively impacted all morphological parameters. However the loss of 30% of the leaves had a positive effect on...

Five-needle white pine species provide important ecosystem services throughout the western U.S., and many of these species have become susceptible to stressors including warmer temperatures, insect epidemics, nonnative disease, and altered disturbance regimes. The objective of this study was to characterize recent broad-scale demographic patterns, including species abundance (i.e., numbers of individuals, tree density, size-class distributions, recruitment, growth rates, mortality rates, and causes of mortality, for the six species of five-needle pine that occur in the western US. We used...

Climate change and a long legacy of fire suppression are leading to an increased prevalence of ‘mega-disturbances’ such as drought and wildfire in terrestrial ecosystems. Evidence for the immediate effects of these novel disturbances on wildlife is accumulating, but little information exists on longer term impacts to species and ecosystems. We studied the occurrence dynamics of an iconic old-forest species, the spotted owl (Strix occidentalis), on a long-term study area in the Sierra Nevada, CA, USA from 1989 to 2020 to evaluate their multi-scale population response following a 2014...