Treesearch

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...

The increasing frequency and severity of forest disturbances challenge the sustainable provision of ecosystem services by forests, and this is true even in regions with net forest growth. The combination of ecosystem service losses from forest disturbances that are immediate as well as the slower post-disturbance process of forest regrowth could result in long-lasting social, economic, and environmental costs. Using economic and geospatial analysis, we estimate the value of recreational services losses due to drought and quantify the social cost of carbon emissions due to wildfires and...

Ponderosa pine (Pinus ponderosa) forests are increasingly experiencing high-severity, stand-replacing fires. Whereas alterations to aboveground ecosystems have been extensively studied, little is known about soil fungal responses in fire-adapted ecosystems. We implement a chronosequence of four different fires that varied in time since fire, 2 years (2015) to 11 years (2006) and contained stands of high severity burned P. ponderosa in eastern Washington and compared their soil fungal communities to adjacent unburned plots. Using Illumina Miseq (ITS1), we examined changes in soil nutrients,...

Management aimed at regenerating softwoods and hardwoods in the same stand (i.e., a mixedwood) has some appeal in the pine-hardwood forests of the southern United States. We revisited a group selection experiment installed in 1991 to evaluate the influence of gap size and site preparation treatments on a pine-hardwood stand in Louisiana, USA. Experimental treatments included a factorial combination of three group opening sizes (0.1, 0.25, 0.4 ha) and three methods of site preparation (chemical, mechanical, untreated) in the harvest gaps. Specifically, we tested two hypotheses: 1) regenerati...

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...

Mountain ecosystems contain strong elevational gradients in climate and vegetation that shape species distributions and the structure of animal communities. Nevertheless, studies of habitat selection for individual species rarely account for such gradients that often result in species being managed uniformly across their range, which may not improve conservation as intended. Therefore, we characterized variation in nocturnal habitat selection by 18 GPS-tagged California spotted owls (Strix occidentalis occidentalis) along a 1400-m elevational gradient in the Sierra Nevada, California. We...

Soil microbial communities occupy the most biologically diverse habitats in the world. A single gram of soil can support more than several thousand fungal taxa near the root rhizosphere (Buée et al., 2009). As mentioned in other chapters in this book, many factors can influence the microbial communities associated with tree leaves, stems, and roots. Differences in host species (Prescott and Grayston, 2013), cultivar type within a species, soil type, physiological status of host, and pathogen presence can influence variation in microbial communities (Costa et al., 2007; Aira et al., 2010;...

In 1990, Europe, North America, and the Asian democracies of Japan, Taiwan, and South Korea (JTK) were the major export markets for U.S. hardwood lumber and oak species accounted for 59 percent of total exports. In the 1990s, shipments to Europe and North America increased, while shipments to JTK declined. During the early 2000s, exports to China and Vietnam (CHV) increased. The worldwide recession of 2009 caused exports to decline in all regions, and oak species accounted for 37 percent of total shipments that year. Since 2010, CHV has become the most important export market for all...