In the early 1980s, nitrogen (N) deposition was first postulated as a cause of N saturation and spruce mortality across the northeastern US. In 1988, a series of high elevation spruce-fir forest N addition plots were established on Mt. Ascutney (southeastern) Vermont to test this hypothesis. The paired plots each received, in addition to ambient N deposition, 15.7 kg N ha-' (low N addition), 31...

Materials and Methods The Neely-Kinyon LTAR site was established in 1998 to study the long-term effects of organic production in Iowa. Treatments at the LTAR site, replicated four times in a completely randomized design, include the following rotations: conventional CornSoybean (C-S), organic Corn-SoybeanOats/Alfalfa (C-S-O/A), organic CornSoybean-Oats/Alfalfa-Alfalfa (C-S-O/A-A) and organic Co...

The responses of dwarf black mangroves (Avicennia germinans) and components of the microbial community to the addition of nitrate over a 2-year period were examined. The field study was conducted in the Indian River Lagoon (Florida) in a mangrove-dominated impoundment that was established for purposes of mosquito control. The responses of mangroves to the regular addition of nitrate were insign...

We determined the effects of subsoiling on woody lateral roots and enzyme activities involved in stem carbon metabolism of 90- to 100-year-old Jeffrey pine (Pinus jeffreyi Grev. and Balf.) growing on the eastern side of the California Sierra Nevada Range. Twelve 1.0-ha plots were established on each of two sites. Four site treatments-thinning and subsoiling entire plots, thinning and no subsoil...

Air pollution affects forest health through atmospheric deposition of acidic and nitrogen compounds and elevated levels of tropospheric ozone (O3). In 1985, a monitoring network was established across Europe and various research efforts have since been undertaken to define critical values. We measured atmospheric deposition of acidity and nitrogen as well as ambient levels of O3 on 12, 13, and ...

Forest dynamics were studied from 1993 to 1997 for individuals > 10 cm DBH in nine 1 ha permanent sample plots. They were established in natural flood plain forests located on the lower Ucayali river in the Peruvian Amazon. After inventories of three plots in each of three forest types, a light and a heavy felling treatment were applied to each of the two plots, while a third plot was kept untr...

—Endangered Interior Least Terns ( Sterna antillarum athalassos ) and threatened Piping Plovers ( Charadrius melodus ) nest in Nebraska at gravel mines where they are vulnerable to disturbance and nest loss. Conflicts occur when their nesting and protected status delay mining activities. The possibility of shifting nesting from active to inactive mining areas by using a deterrent (mylar flaggin...

An invasive shrub, Chinese privet (Ligustrum sinense Lour.), was removed from heavily infested riparian forests in the Georgia Piedmont in 2005 by mulching machine or chainsaw felling. Subsequent herbicide treatment eliminated almost all privet by 2007. Recovery of plant communities, return of Chinese privet, and canopy tree growth were measured on removal plots and heavily invaded control plot...

1. We tested for density-dependent regulation of biomass in a population of the fire ant Solenopsis invicta and examined the mechanisms of population recovery following replicated colony removals. 2. All colonies were killed within the core area (1018 m 2 ) of six plots, while six additional plots served as undisturbed controls. Over the next 5 years, colonies were mapped several times per year...

The main purpose of the study was absorption heavy metals in leaves forest tree species, which were planted two different plots for forestry use and environmental restoration. Four species studied Pinus brutia, Robinia pseudoacaccia, Quercus trojana Fraxinus ornus. Forty-eight leaf samples collected consisted six from each at plot. metal concentrations measured following nine metals: iron (Fe),...