Treesearch

Research involving nutrients and biogeochemistry has a long history at the Coweeta Hydrologic Laboratory (CHL). The majority of nutrient research has focused on nitrogen (N), phosphorus (P), and dissolved organic carbon (DOC), and less so on other nutrients such as calcium (Ca). This chapter reviews research at the CHL on watershed biogeochemistry and stream organismal and ecosystem responses to nutrient enrichment, with primary attention to N and P. It also identifies future research at CHL that could fill science gaps that are of high priority for regulators and suggests ways that...

Green infrastructure (GI) initiatives, including programs to plant trees and install bioswales, have been adopted by a growing number of local government and non-governmental organizations. While the details of these programs vary, a common characteristic of most Canadian and US GI initiatives is a distributed approach that includes both public and private land. To date, little research has explored residents’ knowledge of GI or their engagement with related initiatives even though residents' installation of GI is often key to creating distributed GI networks. In this study, we (1) assess...

Plant phenological processes significantly impact ecosystem function and services across multiple ecological scales and are widely viewed to be among the most sensitive indicators of global environmental change. Remote sensing has crucially expanded our understanding of phenological variability. Yet, we continue to lack a complete mechanistic understanding of phenology and its variability and drivers, which is important to the development of predictive models, especially under continued environmental change. We combined field inventories and Land Surface Phenology (LSP) approaches, using...

Variations in both the behavior of wildlife and the scale at which the environment most influences the space use of wild animals (i.e., scale of effect) are critical, but often overlooked in habitat selection modeling. Ecologists have proposed that biological responses happening over longer time frames are influenced by environmental variables at larger spatial scales, but this has rarely been empirically tested. Here, we hypothesized that long-term patterns of behavior (i.e., lasting multiple weeks to months) would be associated with larger scales of effect than more sporadic behaviors....

The Marcell Experimental Forest (MEF) has a rich and long history of research focused on peatland hydrology and biogeochemistry (Kolka et al. 2011c). Research at MEF has encompassed atmospheric deposition chemistry, peatland nutrient cycling, mercury (Hg) cycling, soil properties, tree-stand dynamics, and climate change. Various watershed treatments have been applied to uplands, bogs, or fens to investigate impacts of management practices on water yield, peak streamflow, water quality, and nutrient processing (Kolka et al. 2011b, Verry et al. 2011a). Biogeochemical research at MEF has...

Anoplophora chinensis (Forster) is a xylophagous invasive cerambycid whose larvae feed on the lower bole and exposed roots of many tree species in orchard, urban, and forested habitats. Larval survival and development of A. chinensis from Italy and China were evaluated at eight constant temperatures (5, 10, 15, 20, 25, 30, 35, and 40°C). Development was slow or did not occur at temperatures ≤10 and >35°C. The TMin for the first six instars and the pupa was <10°C, while TMin for the higher instars was closer to 12°C. The ultimate instar for both populations was insensitive to temperature....

A warming climate and extended growing season may confer competitive advantages to temperate conifers that can photosynthesize across seasons. Whether this potential translates into increased growth is unclear, as is whether pollution could constrain growth. We examined two temperate conifers—eastern white pine (Pinus strobus L.) and eastern hemlock (Tsuga canadensis (L.) Carrière)—and analyzed associations between growth (476 trees in 23 plots) and numerous factors, including climate and pollutant deposition variables. Both species exhibited increasing growth over time and eastern white...

Although Dutch elm disease (DED) is the primary threat to American elm (Ulmus americana L.), we hypothesized that shoot freezing injury may also limit tree productivity and survival in the north. We assessed shoot cold tolerance and field winter injury of American elm bred for DED tolerance planted in Lemington, Vermont. We tested for differences in cold tolerance associated with date, maternal DED tolerance sources, paternal sources from plant hardiness zones 5a, 6a, and 6b (determined using data from 1996 to 2005), and the interactions of these. Cold tolerance was greatest in the winter,...

Dispersal is a key process that impacts population dynamics and structures biotic communities. Dispersal limitation influences the assembly of plant and microbial communities, including mycorrhizal fungi and their plant hosts. Mycorrhizal fungi play key ecological roles in forests by feeding nutrients to plants in exchange for sugars, so the dispersal of mycorrhizal fungi spores actively shapes plant communities. Although many fungi rely on wind for spore dispersal, some fungi have lost the ability to shoot their spores into the air and instead produce enclosed belowground fruiting bodies...

Evaluating the cold tolerance of biological control agents is often necessary to optimize their release and performance. We used field and laboratory assays to determine the cold hardiness of the parasitoid Spathius galinae Belokobylskij & Strazanac, an approved classical biological control agent of emerald ash borer (Agrilus planipennis Fairmaire) in North America. Supercooling points and lower lethal temperature of mature (cocooned) S. galinae larvae were measured in controlled cooling assays in the laboratory. Most S. galinae larvae died after reaching their supercooling point, which...