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Using foliar and forest floor mercury concentrations to assess spatial patterns of mercury deposition
2015
Blackwell, Bradley D. | Driscoll, Charles T.
We evaluated spatial patterns of mercury (Hg) deposition through analysis of foliage and forest floor samples from 45 sites across Adirondack Park, NY. Species-specific differences in foliar Hg were evident with the lowest concentrations found in first-year conifer needles and highest concentrations found in black cherry (Prunus serotina). For foliage and forest floor samples, latitude and longitude were negatively correlated with Hg concentrations, likely because of proximity to emission sources, while elevation was positively correlated with Hg concentrations. Elemental analysis showed moderately strong, positive correlations between Hg and nitrogen concentrations. The spatial pattern of Hg deposition across the Adirondacks is similar to patterns of other contaminants that originate largely from combustion sources such as nitrogen and sulfur. The results of this study suggest foliage can be used to assess spatial patterns of Hg deposition in small regions or areas of varied topography where current Hg deposition models are too coarse to predict deposition accurately.
显示更多 [+] 显示较少 [-]Perspectives regarding 50 years of research on effects of tropospheric ozone air pollution on US forests
2007
Karnosky, D.F. | Skelly, J.M. | Percy, K.E. | Chappelka, A.H.
Tropospheric ozone (O3) was first determined to be phytotoxic to grapes in southern California in the 1950s. Investigations followed that showed O3 to be the cause of foliar symptoms on tobacco and eastern white pine. In the 1960s, “X” disease of ponderosa pines within the San Bernardino Mountains was likewise determined to be due to O3. Nearly 50 years of research have followed. Foliar O3 symptoms have been verified under controlled chamber conditions. Studies have demonstrated negative growth effects on forest tree seedlings due to season-long O3 exposures, but due to complex interactions within forest stands, evidence of similar losses within mature tree canopies remains elusive. Investigations on tree growth, O3 flux, and stand productivity are being conducted along natural O3 gradients and in open-air exposure systems to better understand O3 effects on forest ecosystems. Given projected trends in demographics, economic output and climate, O3 impacts on US forests will continue and are likely to increase. Elevated tropospheric ozone remains an important phytotoxic air pollutant over large areas of US forests.
显示更多 [+] 显示较少 [-]Evaluation of ozone injury on foliage of black berry (Prunus serotina) and tall milkweed (Asclepias exaltata) in Great Smoky Mountains National Park
1997
Chappelka, A. | Renfro, J. | Somers, G. | Nash, B. (School of Forestry, Auburn University, Auburn, AL 36849 (USA))
Observations of ozone-induced foliar injury on black cherry (Prunus serotina, var. capuli) within the Desierto de Los Leones National Park, Mexico City
1997
Skelly, J.M. | Savage, J.E. | Bauer, M. de L. de | Alvarado, D. (Department of Plant Pathology, Pennsylvania State University, University Park, PA 16802 (USA))
Aerobic ethanol production by leaves: evidence for air pollution stress in trees of the Ohio River Valley, USA
1989
MacDonald, R.C. | Kimmerer, T.W. | Razzaghi, M. (Department of Forestry, University of Kentucky, Lexington, KY 40546-0073 (USA))
Issues in scaling tree size and age responses to ozone: a review
1997
Kolb, T.E. | Fredericksen, T.S. | Steiner, K.C. | Skelly, J.M. (School of Forestry, College of Ecosystem Science and Management, Northern Arizona University, Flagstaff, Arizona 86011-5018 (USA))
Size-mediated foliar response to ozone in black cherry trees
1996
Fredericksen, T.S. | Skelly, J.M. | Steiner, K.C. | Kolb, T.E. | Kouterick, K.B. (Environmental Resources Research Institute, 220 Forest Resources Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802 (USA))
Physiology, morphology, and ozone uptake of leaves of black cherry seedlings, saplings, and canopy trees
1995
Fredericksen, T.S. | Joyce, B.J. | Skelly, J.M. | Steiner, K.C. | Kolb, T.E. | Kouterick, K.B. | Savage, J.E. | Snyder, K.R. (Environmental Resources Research Institute, 220 Forest Resource Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802 (USA))
Tree Response to Experimental Watershed Acidification
2014
Jensen, N. K. | Holzmueller, E. J. | Edwards, P. J. | Gundy, M Thomas-Van | DeWalle, D. R. | Williard, K. W. J.
Forest ecosystems in the Eastern USA are threatened by acid deposition rates that have increased dramatically since industrialization. We utilized two watersheds at the Fernow Experimental Forest in West Virginia to examine long-term effects of acidification on ecological processes. One watershed has been treated with ammonium sulfate (approximately twice the ambient deposition rate) since 1989 to simulate elevated acidic deposition, while the other served as a control. Prior to treatment, both watersheds were similar in age and species composition. Ten dominant overstory Prunus serotina and Liriodendron tulipifera trees were selected and cored from each watershed to measure bolewood concentrations of essential elements through time. In addition, changes in tree species basal area were analyzed utilizing 50 long-term growth plots. Results of this experiment show lower calcium and magnesium concentration and increased acidic cation concentration for both species in the treated watershed, indicating a negative treatment effect. Growth response, measured through relative growth rates of cored trees and changes in basal area from growth plots, was not as conclusive and appeared to differ by species. The resulting difference in species response indicates that acidification sensitivity is something that land managers should consider when managing forests affected by acidification.
显示更多 [+] 显示较少 [-]Foliar sensitivity of eight eastern hardwood tree species to ozone
1992
Davis, D.D. (Pennsylvania State Univ., University Park, PA (USA). Dept. of Plant Pathology) | Skelly, J.M.