Treesearch

To continue the reflections on the 30 year anniversary of the Allerton Park Workshop as initiated by Wu (2013), we present some reflections of the situation just before and developments after the workshop from two participants—one who was a chief organizer and synthesizer of the workshop as well as lead author of the subsequent document (and this piece), and one who was a brand new entrant into the newly formulated and wonderfully fascinating field of landscape ecology at the time of the workshop.

The increasing availability of satellite imagery has spurred the production of thematic land cover maps based on satellite data. These maps are more valuable to the scientific community and land managers when the accuracy of their classifications has been assessed. Here, we assessed the accuracy of a map of forest disturbance in the watersheds of Lake Superior and Lake Michigan based on an improved version of the Vegetation Change Tracker algorithm (VCTw). We constructed a probability-based sampling design using two stages of sampling with stratification at each stage. Results are presented...

This bulletin describes forest resources of the State of Louisiana at the time of the 2005 forest inventory. It is based on sampling conducted by the U.S. Department of Agriculture Forest Service, Southern Research Station, Forest Inventory and Analysis. This bulletin addresses forest area estimates; timber growth, removals, and mortality; invasive species; and timber product output.

Long-term weather and hydrology data from the Santee Experimental Forest were used to assess trends in air temperature, precipitation, and the water balance in gauged watersheds over a 63-year period. Since 1946, the mean annual air temperature has increased at a rate of 0.19 °C per decade, a rate higher than the global mean for the same period. Total annual precipitation has not changed significantly over the period of 1946–2008; however, large storm events (>50 mm precipitation) have increased 21 percent over the 63-year period. Annual stream discharge has varied from 5.5 percent of...

This report describes how the American chestnut (Castanea dentata) was ecologically extirpated due to an exotic pathogen, the chestnut blight (Cryphonectria parasitica), and describes current restoration efforts. The habitat, life history, special uses, and genetics of the American chestnut are detailed. The American chestnut was an important and versatile tree species until its demise from the chestnut blight. Backcross breeding techniques, the use of hypovirulent blight strains, and genetic engineering programs are currently being developed and tested to produce trees resistant to the...

The 626 million acres of forests in the conterminous United States represent significant reserves of biodiversity and terrestrial carbon and provide substantial flows of highly valued ecosystem services, including timber products, watershed protection benefits, and recreation. This report describes forecasts of forest conditions for the conterminous United States in response to multiple scenarios evaluated by the 2010 Resources Planning Act Assessment. The results are based on the U.S. Forest Assessment System, a modeling system designed to forecast alternative futures for U.S. forests,...

Fire behavior modeling and geospatial analyses can provide tremendous insight for land managers as they grapple with the complex problems frequently encountered in wildfire risk assessments and fire and fuels management planning. Fuel management often is a particularly complicated process in which the benefits and potential impacts of fuel treatments need to be demonstrated in the context of land management goals and public expectations. The fuel treatment planning process is complicated by the lack of data assimilation among fire behavior models and weak linkages to geographic information...

Invasive species are widely recognized as altering species and community dynamics, but their impacts on biogeochemical cycling and ecosystem processes are less understood. The emerald ash borer (Agrilus planipennis Fairmaire) is a phloem feeding beetle that was inadvertently introduced to the US in the 1990s and relies solely on ash trees (Fraxinus spp.) to complete its life cycle. Ash trees have a wide geographic distribution and are an important component of many different forest types in the US. The larval feeding behavior of the emerald ash borer (EAB) effectively girdles the tree's...

Surface ozone (O3) was measured at the Devils Postpile National Monument (DEPO), eastern Sierra Nevada Mountains, California, during the 2007 (low-fire) and 2008 (high-fire) summer seasons. While mean and median values of O3 concentrations for the 2007 and 2008 summer seasons were similar, maximum O3 concentrations in June and August 2008 were higher than in any month of the 2007 summer season. This increase of maximum concentrations in the high-fire year is attributed to emissions of O3 precursors from wildland fires upwind of DEPO in addition to transport of polluted air from the...

To examine whether stream nitrogen concentrations in forested reference catchments have changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr of data collected from 22 catchments at seven USDA Forest Service Experimental Forests. Trends in stream nitrogen presented high spatial variability both among catchments at a site and among sites across the USA. We found both increasing and decreasing trends in monthly flow-weighted stream nitrate and ammonium concentrations. At a subset of the catchments, we found that the length and period of analysis...