Treesearch

We now live in a world dominated by humans (the Anthropocene), whose activities on Earth are resulting in new habitats and new environmental conditions, including climate change. To many, the Anthropocene is an era of environmental doom that unless reversed, will result in catastrophic reductions in biodiversity. An alternate view is that the biota will adjust to the new environmental conditions and through processes of species mixing and self-organization will form sustainable novel communities of organisms. Using examples from Puerto Rico, I discuss the conditions that lead to novel...

Measurements of bark thickness generally ignore the fact that bark is comprised of both living inner bark (phloem) and essentially dead outer bark (rhytidome).Discerning between them has ramifications for the utility of bark as a byproduct of timber harvesting and its functionality on a living tree. Inner bark and outer bark thicknesses for longleaf pine (Pinus palustris Mill.) were investigated using disks collected from trees harvested on a 70-year-old plantation. Inner bark thickness was relatively constant up the bole of each tree whereas outer bark thickness rapidly declined from its...

The use of clonal varieties in forestry offers great potential to improve growth traits (quantity) and wood properties (quality) of loblolly pine (Pinus taeda L.). Loblolly pine trees established via somatic embryogenesis (clones), full-sib zygotic crosses, and half-sib zygotic open-pollinated families were sampled to identify variation in growth and wood properties among and within clonal lines and zygotic controls. Increment cores 5mmin diameter were collected at age 4 from a total of 2615 trees. Growth properties (diameter at 1.4 m and total tree height) and wood properties (whole-core...

Spatial variation of urban surface air temperature and humidity influences human thermal comfort, the settling rate of atmospheric pollutants, and plant physiology and growth. Given the lack of observations, we developed a Physically based Analytical Spatial Air Temperature and Humidity (PASATH) model. The PASATH model calculates spatial solar radiation and heat storage based on semiempirical functions and generates spatially distributed estimates based on inputs of topography, land cover, and the weather data measured at a reference site. The model assumes that for all grids under the...

Giant reed was evaluated for enzymatic hydrolysis and simultaneous saccharification and fermentation(SSF) using a commercial cellulase/β-glucosidase and Scheffersomyces (Pichia) stipitis CBS 6054 for ethanolproduction following dilute-oxalic acid pretreatment. A response surface methodology with two inputparameters – severity factor (SF) and oxalic acid concentration (OA) – was employed to optimize bothenzymatic hydrolysis and SSF. Xylan content after dilute-OA pretreatment decreased with increasingSF and OA; almost complete hydrolysis was observed when the harsher pretreatment conditions...

A distributed adaptation of i-Tree Eco was used to simulate dry deposition in an urban area. This investigation focused on the effects of varying temperature, LAI, and NO2 concentration inputs on estimated NO2 dry deposition to trees in Baltimore, MD. A coupled modeling system is described, wherein WRF provided temperature and LAI fields, and CMAQ provided NO2 concentrations. A base case simulation was conducted using built-in distributed i-Tree Eco tools, and simulations using different inputs were compared against this base case. Differences in land cover classification and tree cover...

Methylmercury, a potent neurotoxin, can damage health of humans and wildlife. In 2012, we collected 73 blood and feather samples from birds among diverse foraging guilds to assess mercury exposure in wetland habitats associated with Lakes Managua and Nicaragua. Blood levels (0.72 parts per million) in a piscivorous Neotropic Cormorant Phalacrocorax brasilianus from Lake Managua exceeded the United States Environmental Protection Agency recommended screening value for fish consumption of 0.3 ppm. Cormorants should be considered as an upper trophic level bioindicator of aquatic Hg toxicity....

Federal wildland fire policy requires that publicly owned lands with burnable vegetation have a fire management plan (FMP); this applies to the five primary Federal fire agencies (Bureau of Indian Affairs, Bureau of Land Management, National Park Service, U.S. Fish and Wildlife Service, and Forest Service). FMPs are based on land and resource management plans and are intended to provide guidance for managers responding to wildland fire incidents. FMPs summarize information on the basis of fire management units (FMUs), which divide landscapes into smaller geographic areas according to...

The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several...

The fisher (Pekania pennanti) is a species of conservation concern throughout the Pacific coastal region in North America. A number of radiotelemetry studies of habitat selection by fishers at resting sites have been conducted in this region, but the applicability of observed patterns beyond the boundaries of each study area is unknown. Broadly applicable information on habitat selection by fishers in this region would be useful for conservation planning and for informing forestmanagement decisions in areas where intensive field studies have not been conducted. To provide such information,...