Treesearch

Forest patches in urban landscapes make outsized contributions to biodiversity, ecosystem function, and human health and well-being. However, urbanization can alter environmental conditions that underpin forest health. Most studies of forest health in urban landscapes have focused on few forest patches across a single metropolitan region, and synthesis is needed to understand broader patterns. We assessed variation among measures of forest health across land cover gradients and ecoregions by determining (1) whether the degree of urban, agricultural, and forested land surrounding a forest...

A long-term study of forest management, like the one established in the 1950s by the U.S. Department of Agriculture, Forest Service at the Penobscot Experimental Forest in Maine, provides a unique opportunity for landowners to learn about different approaches to management and their outcomes. After more than 70 years of research at the Penobscot Experimental Forest, it has become apparent that the management approaches applied have changed the species composition, tree quality, wildlife habitat, carbon storage, productivity, and financial value of the forest. The side-by-side comparisons...

The U.S. Department of Agriculture, Forest Service National Best Management Practices (BMP) Program assists in meeting agency Clean Water Act objectives with nationally consistent monitoring. National BMP program monitoring protocols are used to evaluate BMP implementation (including planning) and effectiveness for most types of land-disturbing activities that occur on national forests and grasslands. This report summarizes data from the first two full monitoring periods—federal fiscal years 2015–2016 and 2017–2018—for aquatic ecosystems, chemical uses, facilities and nonrecreation special...

The emerald ash borer [Agrilus planipennis Fairmaire (Coleoptera:Buprestidae)] was first discovered in the United States in 2002 near Detroit, Michigan, and has spread quickly throughout the eastern United States and Canada, with isolated populations as far west as Oregon and British Columbia. Because ash trees in North America lack natural resistance to the beetle, emerald ash borer populations grew very quickly and have killed more than 100 million native ash trees. Since 2003, researchers with the U.S. Department of Agriculture, Forest Service, Northern Research Station have studied...

National forest inventory (NFI) programs provide vital information on forest parameters' status, trend, and change. Most NFI designs and estimation methods are tailored to estimate status over large areas but are not well suited to estimate trend and change, especially over small spatial areas and/or over short time periods (e.g. annual estimates). Fine-scale space-time indexed estimates are critical to a variety of environmental, ecological, and economic monitoring efforts. In the United States, for example, NFI data are used to estimate forest carbon status, trend, and change to support...

Forest canopy complexity (i.e., the three-dimensional structure of the canopy) is often associated with increased species diversity as well as high primary productivity across natural forests. However, canopy complexity, tree diversity, and productivity are often confounded in natural forests, and the mechanisms of these relationships remain unclear. Here, we used two large tree diversity experiments in North America to assess three hypotheses: (1) increasing tree diversity leads to increased canopy complexity, (2) canopy complexity is positively related to tree productivity, and (3) the...

Until it was discovered in Boulder, Colorado in 2013, the invaded range of the emerald ash borer, Agrilus planipennis, in the Western Hemisphere was entirely limited to natural and urban forests of eastern North America. Subsequently, this species has expanded its range through much of the Colorado Front Range region, utilizing non-native ash, Fraxinus spp. These host trees are widely planted there in urban settings but natural forests containing ash are lacking in the region. Here we use survey data to quantify emerald ash borer regional spread across the Colorado Front Range as well as...

Propagule pressure is one of the key drivers of establishment success of non-native species, including insects. However, border interception data, which have the potential to act as a proxy for true arrival rates (i.e., propagule pressure) of insects into a country, are seldom used to predict invasions. This can be due to the limited amount of interception data in some countries, difficulties accessing such data, and when these data are available, difficulties in addressing biases caused by variation in interception probability for different taxa due to policy changes, and operational...

A new subgenus and four new species of Adelges (Hemiptera: Adelgidae) are described from Bhutan. To support their taxonomic placement, we provide a phylogeny of Adelgidae reconstructed using mitochondrial and nuclear DNA sequence data. Cassiadelges subgen. nov is distinguished by the combination of feeding on Larix secondary hosts, having tergites of the head and pronotum fused into a cephaloprothoracic shield, and having only acuminate setae on the terminal abdominal segments. Adelges (Cassiadelges) coccipus sp. nov. feeds on Larix griffithii. This remarkable species is the only known...

This document contains abstracts and papers of the oral and poster presentations offered at the 31st annual U.S. Department of Agriculture interagency research forum on invasives species held in Annapolis, MD, in January 2023. The forum, sponsored by the Forest Service, Animal and Plant Health Inspection Service, National Institute of Food and Agriculture, and Agricultural Research Service, illustrates the depth and breadth of studies supported by the agencies and their cooperators.