Treesearch

This report summarizes the potential impacts of N and S deposition on 94 of the most common tree species across the contiguous United States, compiling information from several peer-reviewed Federal and non-Federal sources. We provide information on how the rates of growth and survival for each species respond to N and S deposition, and the ecological roles and ecosystem services provided by these species. This report is part of a three-volume series covering trees (this Volume 1), lichens (Volume 2), and herbaceous understory species (Volume 3). In this volume, we include five categories...

Efficient separation of insects from plant material for quantification and collection is an important component of entomological research. This paper reports on a novel, easily replicable container designed to efficiently collect two different biological control agents dispersing from hemlock (Tsuga spp.) foliage infested with the invasive hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae). The container utilizes a simplified Berlese-style funnel design to collect Laricobius spp. (Coleoptera: Derodontidae) larvae dropping from the foliage into a removable bottom...

The impact of fuelwood harvesting on forest structure and composition is not clear, especially on the understudied and scarce Arasbaran forests in Iran. This research compared woody species density, species diversity, forest composition, and regeneration status in areas of continuous and ceased fuelwood harvesting in Arasbaran forests. We expected fuelwood harvesting to decrease stem density, species diversity, tree size (diameter at the breast height (DBH) and height), and shift composition away from preferred fuelwood species. We measured woody species size and frequency and identified...

In addition to impacts on human health and the economy, COVID-19 is changing the way humans interact with open space. Across urban to rural settings, public lands–including forests and parks – experienced increases and shifts in recreational use. At the same time, certain public lands have become protest spaces as part of the public uprisings around racial injustice throughout the country. Land managers are adapting in real-time to compound disturbances. In this study, we explore the role of the public land manager during this time across municipal and federal lands and an urban-rural...

The hydrological functioning of urban trees can reduce stormwater runoff, mitigate the risk of flood, and improve water quality in developed areas. Tree canopies intercept rainfall and return water to the atmosphere through transpiration, while roots increase infiltration and storage in the soil. Despite this, the amount of stormwater that trees remove through these functions in urban settings is not well characterized, limiting the use of urban forests as practical stormwater management strategies. To address this gap, we use ecohydrological approaches to assess the transpiration rates of...

Throughout much of its range, northern white-cedar (Thuja occidentalis L., hereafter cedar) has experienced a bottleneck in recruitment: cedar seedlings are often abundant in these stands, particularly in lowland settings, yet cedar sapling densities are quite low, leading to concerns that cedar canopy trees are not being replaced. Several barriers to cedar recruitment have been suggested; however, findings from previous studies have been inconsistent with regard to limiting factors. Our objective was to characterize the microsite conditions associated with the establishment of cedar...

Urban trees play an important role in helping cities adapt to climate change, but also are vulnerable to changes in climate themselves. We developed an approach for assessing vulnerability of urban tree species and cultivars commonly planted in cities in the United States Upper Midwest to current and projected climate change through the end of the 21st century. One hundred seventy-eight tree species were evaluated for their adaptive capacity to a suite of current and future-projected climate and urban stressors using a weighted scoring system based on an extensive literature review. These...

In 1978, Reece Sailer published a seminal retrospective entitled ‘Our Immigrant Insect Fauna.’ His goals were to better understand the origins and historical patterns of alien insect species introductions into the United States and establish a baseline for future work to improve our ability to respond to environmental and agricultural wellbeing threats. We updated Sailer’s study to include information on species introduced recently into the United States and that are now targeted by regulatory agencies. The recent trends (recorded through 2016) are different from those reported by Sailer....

Dams and the reservoirs they create are notorious for disrupting the migration of salmon, both when they travel downstream as juveniles and when they return to spawn years later as adults. In an effort to improve downstream salmon migration, the U.S. Army Corps of Engineers in 2011 began yearly, short-term draining of Fall Creek Reservoir located on a tributary of the Willamette River in Oregon. The reservoir is drained down to the streambed over one week every autumn. The full effects of this novel practice were largely unknown until researchers Sherri Johnson and Christina Murphy...

Forests in the southwestern USA are well adapted to dry conditions. High lightning incidence, long human habitation, and frequently windy conditions make the Southwest stand out for a high pace of burning. Forests are structured by climatic gradients created by elevation and topography. Low-elevation woodlands experience the driest conditions, but low productivity limits fuels. At the other extreme, high-elevation forests produce abundant fuels but are rarely dry enough to burn. The "sweet spot" in the middle elevations, dominated by pines and other mixed conifers, is characterized by...