Treesearch

The Renewable Resources Planning Act of 1974 requires the USDA Forest Service to conduct assessments of resource conditions. This report fulfills that need and focuses on quantifying extent, productivity, and health of U.S. rangelands. Since 1982, the area of U.S. rangelands has decreased at an average rate of 350,000 acres per year owed mostly to conversion to agricultural and residential land uses. Nationally, rangeland productivity has been steady over the last decade, but the Rocky Mountain Assessment Region appears to have moderately increased productivity since 2000. The forage...

A collaborative project between the Programa de Fitopatología, Colegio de Postgraduados, Texcoco, Estado de Mexico and the USDA Forest Service - RMRS, Moscow Forest Pathology Laboratory has begun this year (2011) to assess which species of Armillaria are causing widespread and severe damage to the peach orchards from México state, Mexico. We are employing a DNA-based approach in which several genes will be sequenced and compared to known Armillaria species.

Expression of root disease in conifers is often associated with forest practices such as planting, thinning, and harvesting. For example, Armillaria solidipes, a resident microbe, is "triggered" by these practices or application of fertilizer. On the other hand, the connection to forest practices is not so clear when spores of Heterobasidion spp, are delivered to stump surfaces and initiate new infection centers. Natural situations such as ecophysiological maladaptation (McDonald 1991) and insect outbreaks can also trigger expression from resident pest populations. Generally speaking, most...

In 2010, a collaborative project was started to determine the distribution of Armillaria solidipes (= A. ostoyae) in Arizona. The methods and preliminary accomplishments of the 2010 and 2011 (ongoing) field surveys/collections are summarized. During the next phase of this project, surveys will be completed and remaining Armillaria isolates will be identified using DNA-based methods. In addition, a preliminary prediction map based on 25 locations positive for A. solidipes is presented. Sites positive for A. solidipes are associated with climate data to predict the potential current distribut...

Armillaria solidipes (= A. ostoyae) is a root-disease pathogen that causes severe losses in growth and productivity of forest trees throughout the Northern Hemisphere. This species is genetically diverse with variable disease activities across different regions of the world. In North America, A. solidipes in the Colorado Plateau exists in drier habitats and causes more disease on hardwoods in comparison with A. solidipes in the northwestern USA (McDonald 1999). Here, we address 1) the discovery of cryptic genotypes of A. solidipes located within or near the Colorado Plateau region, 2) the...

Puccinia psidii, the cause of eucalypt-guava-'ohi'a-myrtle rust, can infect diverse plants within the Myrtaceae, and this rust pathogen has the potential to threaten numerous forest ecosystems worldwide. Known occurrence records from Brazil, Uruguay, Paraguay, Costa Rica, USA (Hawaii, Florida, and Puerto Rico), and Japan were used to develop bioclimatic models for predicting suitable climate spaces of this rust on a global scale. Four separate models were developed to predict current distribution of suitable climate space for P. psidii: (1) sample points based on all rust occurrence points...

The Forest and Rangeland Renewable Resources Planning Act (RPA) of 1974 requires periodic assessments of the condition and trends of the Nation's renewable natural resources. In this report, we document recent and historical trends in hunting and wildlife watching to fulfill RPA requirements. Using data from the U.S. Department of the Interior, Fish and Wildlife Service's National Survey of Fishing, Hunting, and Wildlife-Associated Recreation we present historical trends back to 1955 as well as recent changes from the past 10 to 20 years to evaluate changes in recreation since the 2000 RPA...

Landscape connectivity, the extent to which a landscape facilitates the movements of organisms and their genes, faces critical threats from both fragmentation and habitat loss. Many conservation efforts focus on protecting and enhancing connectivity to offset the impacts of habitat loss and fragmentation on biodiversity conservation, and to increase the resilience of reserve networks to potential threats associated with climate change. Loss of connectivity can reduce the size and quality of available habitat, impede and disrupt movement (including dispersal) to new habitats, and affect...

Bark beetle outbreaks kill billions of trees in western North America, and the resulting tree mortality can significantly impact local and regional carbon cycling. However, substantial variability in mortality occurs within outbreak areas. Our objective was to quantify landscape-scale effects of beetle infestations on aboveground carbon (AGC) stocks using field observations and remotely sensed data across a 5054 ha study area that had experienced a mountain pine beetle outbreak. Tree mortality was classified using multispectral imagery that separated green, red, and gray trees, and models...

Big sagebrush (Artemisia tridentata Nutt.), a woody shrub, and western larch (Larix occidentalis Nutt.), a deciduous conifer, are among many western North American species that have suffered a decline in presence and natural regeneration across their native ranges. These species are economically, ecologically, and intrinsically valuable, therefore many current restoration and management efforts are working to mitigate their decline. Outplanting container-grown seedlings can expedite the regeneration process and create future propagule sources on sites where other regeneration strategies...