Treesearch

The USDA Forest Service’s Forest Inventory and Analysis (FIA) Program applies specific sampling and analysis procedures to estimate a variety of forest attributes. FIA’s Interior West region uses post-stratification, where strata consist of forest/nonforest polygons based on MODIS imagery, and assumes that nonresponse plots are distributed at random across each stratum. The sample of New Mexico’s forests during 2005-2013 did not meet this assumption due to a large number of private landowners who denied permission to access plots on their properties. We developed a modified stratification...

Wildfire activity continues to plague communities in the American West. Three causes are often identified as key contributors to the wildfire problem: accumulated fuels on public lands due to a history of suppressing wildfires; climate change; and an influx of residents into fire prone areas referred to as the wildland-urban interface (WUI). The latter of these contributors is the focus of much attention. Encouraging homeowners to mitigate wildfire risk on private land has been identified as essential to reducing the devastating effects of wildfires. However, little is known about WUI...

Wildfire activity continues to plague communities in the American West. Three causes are often identified as key contributors to the wildfire problem: accumulated fuels on public lands due to a history of suppressing wildfires; climate change; and an influx of residents into fire prone areas referred to as the wildland-urban interface (WUI). The latter of these contributors is the focus of much attention. Encouraging homeowners to mitigate wildfire risk on private land has been identified as essential to reducing the devastating effects of wildfires. However, little is known about WUI...

Global forests capture and store significant amounts of CO2 through photosynthesis. When carbon is removed from forests through harvest, a portion of the harvested carbon is stored in wood products, often for many decades. The United States Forest Service (USFS) and other agencies are interested in accurately accounting for carbon flux associated with harvested wood products (HWP) to meet greenhouse gas monitoring commitments and climate change adaptation and mitigation objectives. National-level forest carbon accounting has been in place for over a decade, but there is an increasing need...

Incidence of peach [Prunus persica (L.) Batsch] tree mortality attributed to Armillaria root disease was assessed from 2009 to 2011 in 15 orchards in the State of Mexico, Mexico. Incidence increased gradually every year of assessment, reaching average values of 9.7, 15.3 and 20.3% tree mortality and 23.2, 24.7 and 28.3% disease-impacted area of the orchards during 2009, 2010 and 2011, respectively. The cultivars 'Nemaguard' and 'Criollo of La Goleta', a local rootstock used in the region, were both susceptible to the disease. To identify species of Armillaria isolated from infected peach...

Rhodomyrtus tomentosa (Aiton) Hassk. (downy-rose myrtle, family: Myrtaceae), of South Asian origin, is an invasive shrub that has formed monotypic stands in Florida (3). During the winter and spring of 2010 through 2012, a rust disease of epiphytotic proportion was observed on young foliage, stem terminals, and immature fruits of this shrub in natural areas of Martin and Lee counties, Florida. Expanding leaves and succulent stems developed chlorotic flecks on the surface that developed into pustules and ruptured to discharge urediniospores.

Advances in molecular technology provide an accessible set of tools to 1) help forest pathologists detect, identify, and monitor forest pathogens, 2) examine the evolutionary relationships and global distributions of forest pathogens and their hosts, 3) assess the diversity and structure of host and pathogen populations, and 4) evaluate the structure and function of genes, as well as their levels of expression, within species and within communities. This paper briefly outlines DNA-based tools, including molecular diagnostics, phylogenetics, population genetics, genomics, and metagenomics,...

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 )...

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.