Treesearch

Mercury (Hg) in forest runoff varies geographically and in relation to silvicultural practices. There is also considerable uncertainty about how forest management practices, such as residual biomass removal, affect Hg mobilization, and downgradient cumulative effects. In this study, total Hg, dissolved organic carbon (DOC), and sulfate (SO42−) mobilization in runoff were compared among unharvested and harvested hillslopes with and without residual biomass removal, and peat soil and invertebrate methylmercury (MeHg) concentrations were assessed in a down-gradient peatland. Using a before-aft...

The United States (US) Department of Agriculture Forest Service Forest Inventory and Analysis (FIA) program operates the national forest inventory of the US. Traditionally, the FIA program has relied on sample-based approaches—permanent plot networks and associated design-based estimators—to estimate forest variables across large geographic areas and long periods of time. These approaches generally offer unbiased inference on large domains but fail to provide reliable estimates for small domains due to low sample sizes. Rising demand for small domain estimates will thus require the FIA...

Frequent prescribed burning is commonly used to restore and maintain open forest ecosystems in temperate broadleaf regions of the eastern United States. Repeated surface fires reduce the abundance of small woody stems through top-kill or mortality, with implications for age structure and ecosystem development. In this study, we quantified tree recruitment patterns over two decades across two landscape-scale studies in Missouri: the Missouri Ozark Forest Ecosystem Project (a control, with no burning) and the Chilton Creek Management Area (burned on 2–3 year fire return interval). Through...

Trees in the urban right-of-way areas have increasingly been considered part of a suite of green infrastructure practices used to manage stormwater runoff. A paired-catchment experimental design (with street tree removal as the treatment)was used to assess howstreet trees affect major hydrologic fluxes in a typical residential stormwater collection and conveyance network. The treatment consisted of removing 29 green ash (Fraxinus pennsylvanica) and two Norway maple (Acer platanoides) street trees from a medium-density residential area. Tree removal resulted in an estimated 198 m3 increase...

Green ash (Fraxinus pennsylvanica) is the most widely distributed ash tree in North America. Once common, it has experienced high mortality from the non-native invasive emerald ash borer (EAB; Agrilus planipennis). A small percentage of native green ash trees that remain healthy in long-infested areas, termed "lingering ash," display partial resistance to the insect, indicating that breeding and propagating populations with higher resistance to EAB may be possible. To assist in ash breeding, ecology and evolution studies, we report the first chromosome-level assembly from the genus...

Background: People caring for urban green infrastructure, not least urban trees, play an important role in maintaining the quality of the urban environment. But what happens when information processing and knowledge generation become digitalized? This study examines digital tools developed to provide knowledge support and with ambitions of inciting stewardship. It asks what understanding they draw on, what information they broker, and how they approach uptake and use of the content they provide. Methods: We analyzed 6 different e-tools within the context of urban green infrastructure in...

The Sirex woodwasp Sirex noctilio Fabricius (Hymenoptera: Siricidae), a widespread invasive pest of pines in the Southern Hemisphere, was first detected in North America in 2004. This study assessed the impacts of life history traits, host resistance and species interactions on the demography of S. noctilio in New York, Pennsylvania and Vermont, then compared key metrics to those found in the native range in Galicia, Spain. Many trees naturally attacked by S. noctilio in North America produced no adult woodwasps, with 5 of 38 infested trees (13%) sampled across six sites yielding 64% of...

Forest disturbances play a critical role in ecosystem dynamics. However, the methods for quantifying these disturbances at broad scales may underestimate disturbances that affect individual trees. Utilizing individual tree variables may provide early disturbance detection that directly affects tree demographics and forest dynamics. The goals of this study were to (1) describe different methods for quantifying disturbances at individual tree and condition-level scales, (2) compare the differences between disturbance variables, and (3) provide a methodology for selecting an appropriate...

Research has demonstrated that residential yards can provide important habitat for urban birds, pollinators, and other wildlife. In addition, the motivations and constraints underlying decisions to manage traditional lawns, water-conserving yards, native plants, and other landscape types are well understood. Yet relatively little research has addressed people's decisions to adopt wildlife-supporting yards. Analyzing survey data from six U.S. cities, we address three related questions: 1) to what extent do residents choose yard features that support wildlife habitat?; 2) how do yard...

Emerald ash borer (Agrilus planipennis; EAB) has devastated populations of ash (Fraxinus spp.) trees in dozens of U.S. states and Canada over the past few decades. The continued survival of scattered ash trees known as "lingering ash" in heavily infested natural stands, however, offers evidence of genetic resistance or tolerance to EAB. These surviving or "lingering" ash individuals may form the basis for reforestation programs in EAB-impacted areas, and clonal mass-propagation of these genotypes can help accelerate these efforts. Between 2013 and 2018, we initiated embryogenic cultures by...