Treesearch

This article reviews current data on forest wetlands and their economic contributions in the South, ranging from Texas to Virginia. Based on USDA Forest Service Forest Inventory and Analysis (FIA) data, the wetland category comprised 17.7% of timber land area on all private and public lands in the South. This included 4.25 million ha of hydric sites; 0.77 million ha mesic wet; 9.55 million ha mesic, with only seasonal access; for a total of 14.57 million ha. The Natural Resource Inventory (NRI) for 2012 on private lands estimated that there were 14.71 million ha forested wetlands, which...

Historical forests in the Southeastern Mixed Forest province of the United States have been less researched than other regions using historical tree surveys. We used 81,000 tree records from surveys during the 1800s to quantify composition of this ecological province. Upland oaks and pines comprised about 75% of all trees, with relatively equal composition. Oak composition may have comprised ≥ 45% to the northern and eastern sides of the province. Hickories were about 10% of composition and a few species were present at 1% to 2% composition. Currently, pine has increased to 49% composition;...

We examined the contribution of large trees to forest density, richness and biomass using a global network of 48 large (from 2 to 60 ha) forest plots representing 5,601,473 stems across 9,298 species and 210 plant families. This contribution was assessed using three metrics: the largest 1% of trees ≥ 1 cm diameter at breast height (DBH), all trees ≥ 60 cm DBH, and those rank-ordered largest trees that cumulatively comprise 50% of forest biomass.

High-quality information is needed for conservation and management of aquatic resources on lands administered by the U.S. Forest Service (USFS). Information is ultimately derived from data, so the USFS maintains a series of databases that are used to describe the status and trends of aquatic habitats and biota. The databases are spatially explicit and are crowd-sourced, meaning that distributed networks of professionals and technicians operating throughout the National Forest System collect stream and biological measurements, which are stored in central repositories. How those databases...

The Rocky Mountain Research Station recently published a general technical report addressing climate change vulnerability in the Rocky Mountain Region. This report, entitled Climate Change Vulnerability Assessment of Aquatic and Terrestrial Ecosystems in the US Forest Service Rocky Mountain Region, focuses on six ecosystems. Scientists evaluated each ecosystem based on several factors, including their current extent, exposure to climate change, sensitivity and adaptability to climate change, the ability of the ecosystem to shift geographically, and non-climate stressors such as recreational...

Large herbivores act as a major driver of plant litter decomposition in grasslands. The modifications of soil biotic and abiotic properties, as well as the changes in quality (C/N ratio) of plant litter, are two key pathways by which large herbivores can affect litter decomposition. Yet we know little about the relative role of these two mechanisms in mediating decomposition. Here, by combining a large-scale and a small-scale field manipulative experiment, we examined how livestock (cattle and sheep) grazingaffects standing litter decomposition of a dominant grass, Leymus chinensis in...

Unique responses to climate change can occur across intraspecific levels, resulting in individualistic adaptation or movement patterns among populations within a given species. Thus, the need to model potential responses among genetically distinct populations within a species is increasingly recognized. However, predictive models of future distributions are regularly fit at the species level, often because intraspecific variation is unknown or is identified only within limited sample locations. In this study, we considered the role of intraspecific variation to shape the geographic...

Grazing is a major ecosystem disturbance in arid regions that are increasingly threatened by climate change. Understanding the long-term impacts of grazing on rangeland vegetation dynamics in a complex terrain in mountainous regions is important for quantifying dry land ecosystem services for integrated watershed management and climate change adaptation. However, data on the detailed long-termspatial distribution of grazing activities are rare,which prevents trend detection and environmental impact assessments of grazing. This study quantified the impacts of grazing on vegetation dynamics...

Purpose of Review Increased availability of current forest resource information provides an opportunity to evaluate the continued concerns about forest sustainability in North America. The purpose of this study is to assess and discuss the current state and trends of North American forest resources, sustainable forest management, and their implications for forest sustainability. Recent Findings Recent information indicates that forest sustainability in North America is not under threat. Forest area, inventory, and carbon stocks have been increasing while wood harvest has been declining....

Amazonian bird species often have patchy spatial distributions, and previous work has attributed this pattern to habitat specialization and dispersal limitation; however, we know comparatively little about the origins and maintenance of the isolated populations that constitute a patchy distribution. In this study, we ask whether patchy populations are interconnected by dispersal. We formulated 2 alternative hypotheses: (1) patchy populations are relicts of ancient connectivity or dispersal; and (2) patchy populations are centers of local abundance embedded in a matrix of contemporary...