Treesearch

Armillaria plays diverse ecological roles in forests worldwide, which has inspired interest in understanding phylogenetic relationships within and among species of this genus. Previous rDNA sequence-based phylogenetic analyses of Armillaria have shown general relationships among widely divergent taxa, but rDNA sequences were not reliable for separating closely related North American species, such as A. gallica, A. calvescens, A. cepistipes, and A. sinapina, or other closely related Eurasian species (Kim et al. 2006). Recent studies have shown that translation elongation factor 1α (tef-1α )...

Solid and aqueous phase Al species are recognized to affect organic matter (OM) stabilization in forest soils. However, little is known about the dynamics of formation, composition and dissolution of organo-Al hydroxide complexes in microbially-active soil systems, where plant litter is subject to microbial decomposition in close proximity to mineral weathering reactions. We incubated gibbsite-quartz mineral mixtures in the presence of forest floor material inoculated with a native microbial consortium for periods of 5, 60 and 154 days. At each time step, samples were density separated...

Forest fires contribute a significant amount of CO2 to the atmosphere each year, and CO2 emissions from fires are likely to increase under projected conditions of global climate change. In addition to volatilizing aboveground biomass and litter layers, forest fires have a profound effect on belowground carbon (C) pools and the cycling of soil organic matter as a whole. However, the influence of fire on belowground organic matter cycling is not well defined and varies widely with fire severity. We measured soil organic matter (SOM) characteristics across a range of fire severities two years...

Although wildfires are important in many forested ecosystems, increasing suburbanization necessitates management with prescribed fires. The physiological responses of overstory trees to prescribed fire has received little study and may differ from typical wildfires due to the lower intensity and timing of prescribed fire in the dormant season. Trees may be negatively affected by prescribed fires if injury occurs, or positively affected due to reduced competition from understory vegetation and release of nutrients from partially consumed litter. We estimated sap flow and photosynthetic...

DNA-based diagnostics have been successfully used to characterize diverse forest fungi (e.g., Hoff et al. 2004, Kim et al. 2006, Glaeser & Lindner 2011). DNA sequencing of the internal transcribed spacer (ITS) and large subunit (LSU) regions of nuclear ribosomal DNA (rDNA) has proved especially useful (Sonnenberg et al. 2007, Seifert 2009, Schoch et al. 2012) for identification. Most DNA-based identifications of forest fungi involve taxa that have been previously wellcharacterized by morphology or mating tests. However, the efficiency of DNA-based identifications of forest fungi in soils...

A collaborative project between the Programa de Fitopatología, Colegio de Postgraduados, Texcoco, Edo. de México and the USDA Forest Service-RMRS, Moscow Forest Pathology Laboratory began in 2011 to identify which species of Armillaria are causing widespread and severe damage to the peach orchards from México State, México. We are employing a DNA-based approach in which the intergenic spacer 1 region (IGS1) of nuclear rDNA and the translation elongation factor-1 alpha gene will be sequenced and compared to known Armillaria species to facilitate species identification.

Public lands are important constituents of the U.S. carbon (C) balance because they encompass large areas of forests and rangelands, although whether and how C might be actively managed on public lands is not yet clear. A decision to manage public lands for their C benefits would involve a complex set of interacting drivers and multiple jurisdictions, and would, as they are now, be governed by laws mandating multiple uses of land in the public domain.

Efforts to develop a canopy flow modeling system based on the Advanced Regional Prediction System (ARPS) model are discussed. The standard version of ARPS is modified to account for the effect of drag forces on mean and turbulent flow through a vegetation canopy, via production and sink terms in the momentum and subgrid-scale turbulent kinetic energy (TKE) equations. Additionally, a downward decaying net radiation profile inside the canopy is used to account for the attenuation of net radiation by vegetation elements. As a critical step in the model development process, simulations...

Depending on the duration and temperature, heat can adversely affect structural properties of wood. While severe temperatures will result in damage that is visually obvious, damage to wood in terms of structural performance extends to wood that visually appears to be unaffected or only mildly affected. The loss in structural capacity includes both reductions for the duration of the elevated temperature exposure and reductions that are permanent even after normal temperatures are restored. While extensive work has been done to develop techniques for assessing, using nondestructive evaluation...

High spatial resolution three-dimensional (3D) measurements of vegetation by remote sensing are advancing ecological research and environmental management. However, substantial economic and logistical costs limit this application, especially for observing phenological dynamics in ecosystem structure and spectral traits. Here we demonstrate a new aerial remote sensing system enabling routine and inexpensive aerial 3D measurements of canopy structure and spectral attributes, with properties similar to those of LIDAR, but with RGB (red-green-blue) spectral attributes for each point, enabling...