Treesearch

A consensus genetic map for Pinus taeda (loblolly pine) and Pinus elliottii (slash pine) was constructed by merging three previously published P. taeda maps with a map from a pseudo-backcross between P. elliottii and P. taeda. The consensus map positioned 3856 markers via genotyping of 1251 individuals from four pedigrees. It is the densest linkage map for a conifer to date. Average marker spacing was 0.6 cM and total map length was 2305 cM. Functional predictions of mapped genes were improved by aligning expressed sequence tags used for marker discovery to full-length P. taeda transcripts....

For agencies and organizations to effectively manage wildlife, knowledge about the status and trend of wildlife habitat is critical. Traditional wildlife monitoring, however, has focused on populations rather than habitat, because ultimately population status drives long-term species viability. Still, habitat loss has contributed to the decline of nearly all at-risk species (Swift and Hannon 2010) and, as a result, monitoring the amount and quality of habitat can guide recovery efforts for wildlife species with declining trends such as greater sage-grouse (Centrocercus urophasianus) or the...

How do people perceive and value urban green space? In what ways do people's perceptions and values of urban nature affect their use and experience of parks, forest preserves, and other green space types? Knowing this information, how can green space planners, managers, and decision makers facilitate a better "fit" between people and nature in urban settings? Answering these and related questions has been a central goal of the Chicago Urban Field Station, a social science unit of the US Forest Service's Northern Research Station. Since 1978, the forest preserves have been an important...

Oak regeneration problems have been noted in the Missouri Ozarks and elsewhere in the eastern United States. Alteration of disturbance regimes, competition from nonoak species, and high overstory stocking are believed to be major barriers that impede oak regeneration. We studied regeneration in upland oak forests that were harvested by both even-aged (clearcutting) and uneven-aged (single-tree selection and group selection) regeneration methods, focusing on differences in oak regeneration among stands that received alternative harvest treatments. Ten years after treatments, the density of...

The ecological consequences of climate change are predicted to vary greatly throughout US rangelands. Projections show warming and drying in the southern Great Plains and the Southwest, warmer and drier summers with reduced winter snowpack in the Northwest, and warmer and wetter conditions in the northern Great Plains. Primarily through their combined effects on soil water availability, these climatic changes will modify plant production and community composition, which will, in turn, affect the livelihoods of humans who rely upon livestock grazing. The ability of rangeland managers to...

Eastern redcedar (Juniperus virginiana) (ERC) is a conifer native to North America that has been used for a variety of wood products, and its planting has been encouraged to help stabilize soil, reforest abandoned farmland, and provide cover for wildlife. However, ERC tends to expand rapidly and take over certain areas primarily because it can grow on a wide variety of soils and tolerates salt and harsh climatic conditions. As a result of this invasive behavior, the ERC composition of central United States forestlands has been on the rise over several decades. To evaluate the current...

Although knowledge of surface fuel loads is critical for evaluating potential fire behaviour and effects, their inherent variability makes these difficult to quantify. Several studies relate fuel loads to vegetation type, topography and spectral imaging, but little work has been done examining relationships between forest overstorey variables and surface fuel characteristics on a small scale (

We examined the spatial distribution, occurrence, and socioecological predictors of woody invasive plants (WIP) in two subtropical, coastal urban ecosystems: San Juan, Puerto Rico and Miami-Dade, United States. These two cities have similar climates and ecosystems typical of subtropical regions but differ in socioeconomics, topography, and urbanization processes. Using permanent plot data, available forest inventory protocols and statistical analyses of geographic and socioeconomic spatial predictors, we found that landscape level distribution and occurrence of WIPs was not clustered. We...

The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fishers alpha and an approximate pantropical stem total to estimate the minimum number of tropical forest tree species to fall between ~40,000 and ~53,000, i.e., at the high end of previous estimates. Contrary to common assumption, the Indo-Pacific region was found to be as...

1. We assessed the key role of aquatic fungi in modifying coarse particulate organic matter (CPOM) by affecting its breakdown rate, nutrient concentration and conversion to fine particulate organic matter (FPOM). Overall, we hypothesised that fungal-mediated conditioning and breakdown of CPOM would be accelerated when nutrient concentrations are increased and tested the degree to which fungi were critical to CPOM processing and to FPOM production by an invertebrate consumer. 2. We manipulated the presence and absence of fungi, exogenous nutrients [nitrogen (N) and phosphorus (P)] and an...