Treesearch

With well over 600 native species, the southern United States supports one of the richest temperate freshwater fish faunas on Earth (Fig. 10.1 ). Unfortunately, an expert review revealed that 27% (188 taxa) of southern fishes are endangered, threatened, or vulnerable (Warren et al. 2000 ) and that 16–18% of native fishes are imperiled in 45 of 51 major southern river basins. Other groups of aquatic organisms in the region also show high levels of imperilment (e.g., freshwater mussels and gastropods, Neves et al. 1997; Haag 2009; cray fishes, Taylor et al. 1996, 2007; aquatic reptiles,...

Air pollution, including automobile exhaust pollution, can affect anatomical and morphological characteristics of wood. In order to evaluate this subject, the Pinus eldarica trees of Chitgar Park in Tehran, which extends from a crowded highway in the south (polluted site) to the semi polluted midsection and to Alborz Mountain in the north (unpolluted site) were sampled with an increment borer and cores were collected. After cross dating, the tree rings of the last five years were separated from the rest of the core. Anatomical characteristics of the cross sections, including the transition...

The potential for climatic factors as well as soil–plant–climate interactions to change as a result of rising levels of atmospheric CO2 concentration is an issue of increasing international environmental concern. Agricultural and forest practices and managements may be important contributors to mitigating elevated atmospheric CO2 concentrations. A computer model was developed using the Structural Thinking and Experiential Learning Laboratory with Animation (STELLA) software for soil CO2 emissions from a short-rotation woody crop as affected by soil water and temperature regimes, root and...

Prescribed burning is a common management tool for upland hardwood forests, with wildlife habitat improvement an often cited goal. Fire management for wildlife conservation requires understanding how species respond to burning at different frequencies, severities, and over time. In an earlier study, we experimentally assessed how breeding bird communities and species responded to fuel reduction treatments by mechanical understory reduction, low-severity prescribed fires, or mechanical understory reduction followed a year later by high-severity prescribed fires in upland hardwood forest....

Happy 100 years to the Priest River Experimental Forest (PREF)! PREF, which is managed by the Research and Development Branch of the USDA Forest Service, celebrated its centennial in September 2011. It was established in northern Idaho to provide useful information that would improve forest management in the western part of District One at a time when US forestry was in its infancy. In 1911, there were only a handful of university studies on forest development in the United States and little was known about tree establishment and growth, the impact of fire, or how to sufficiently supply...

The National Forests of the United States encompass 192.7 million acres (78 million hectares) of land, which is nearly five percent of the total land area of the nation. These lands are managed by the US Forest Service (USFS) for multiple uses, including extraction of timber, production of fossil fuels and minerals, public recreation, and the preservation of biodiversity, clean air, water, and soils. The USFS is interested in valuing the natural capital within, and the ecosystem services provided by, their lands. This is in part to justify expenditures in a time of limited resources. We...

Turbulent eddies in the planetary boundary layer of the terrestrial planet atmospheres are the primary mechanism by which energy, momentum, gasses, and aerosols are exchanged between the surface and the atmosphere [1]. The importance of eddies has long been recognized by the Earth atmospheric science community, and turbulent theory for Earth has a long history with a massive amount of literature backed by over half a century of detailed field campaigns. Every climate and weather forecasting model in existence relies extensively on turbulent eddy theory supported through observational...

Bark beetles can cause substantial mortality of trees that would otherwise survive fire injuries. Resin response of fire-injured northern Rocky Mountain ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) and specific injuries that contribute to increased bark beetle attack susceptibility and brood production are unknown. We monitored ponderosa pine mortality and resin flow and bark beetle colonization and reproduction following a prescribed fire in Idaho and a wildfire in Montana. The level of fire-caused tree injury differed between the two sites, and the level of tree...

Both the San Francisco Peaks ragwort, Packera franciscana and the La Sal daisy, Erigeron mancus are endemic to treeline/alpine habitats of the single mountain they inhabit. There is little habitat available for these plant species to migrate upward in a warming climate scenario. For P. franciscana, 2008 estimates indicate over 18,000 ramets in a 4 m band along a recreational trail in the Arizona San Francisco Peaks, a trail-side population centroid of 3667 m, and that the population is producing and dispersing seed. We also mapped the 2008 distribution of E. mancus patches a long the La...

We investigate through-thickness hardness and modulus of Zr50Cu45Al5 metallic glass melt-spun ribbon. Because of their thinness, the ribbons are challenging to measure, so we employ a novel nanoindentation based-method to remove artifacts caused by ribbon flexing and edge effects. Hardness and modulus vary approximately linearly across the thickness but, unlike bulk ingots, the side of the ribbon that cooled most quickly had the highest hardness and modulus. This “inverse” variation may be caused by the fast-moving solidification front, which might conceivably, for instance, push free...