HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Kogelmann, W. J. Articles by Sharpe, W. E. Search for Related Content PubMed PubMed Citation Articles by Kogelmann, W. J. Articles by Sharpe, W. E. Agricola Articles by Kogelmann, W. J. Articles by Sharpe, W. E. Related Collections Forest Soils Soil pH Heavy Metals Plant and Soil Interactions Air Pollution

TECHNICAL REPORTS

Heavy Metals in the Environment

Soil Acidity and Manganese in Declining and Nondeclining Sugar Maple Stands in Pennsylvania

^a Department of Crop and Soil Science, Pennsylvania State University, 116 ASI Building, University Park, PA 16802
^b School of Forest Resources and Penn State Institutes of the Environment, Pennsylvania State University, 136 Land and Water Building, University Park, PA 16802

^* Corresponding author (wjk11{at}psu.edu)

Received for publication September 7, 2004. For decades, the hardwood forests of northern Pennsylvania have been subjected to chronic atmospheric loading of acidifying agents. On marginal, high-elevation, unglaciated sites, sugar maples (Acer saccharum Marsh.) have experienced severe decline symptoms and mortality. Accelerated soil acidification, base cation leaching, and increased availability of toxic metals have been suggested as predisposing factors contributing to this decline. Manganese, an essential micronutrient, is also a potentially phytotoxic metal that may be a factor associated with poor sugar maple health on soils vulnerable to acidification from anthropogenic sources. We measured Mn levels in four compartments of the soil–tree system (soil, foliage, xylem wood, and sap) on three sugar maple stands in northern Pennsylvania. Two stands were classified as declining and one was in good health. Negative correlations were found between soil pH and Mn levels in the soil, foliage, sap, and xylem wood. Levels of Mn in these pools were consistently higher on declining sites, which correspondingly exhibited lower levels of Ca and Mg. Species differences between red maple (Acer rubrum L.) and sugar maple at the two declining sites suggested different tolerances to excessive Mn. Molar ratios of Mg/Mn and Ca/Mn were different among sites and showed potential as indicators of soil acidification. Significant correlations among soil, sap, foliage, and xylem wood Mn were also noted. These results show clear Mn differences among sites and, when viewed with recent Mn toxicity experiments and other observational studies, suggest that excessive Mn may play a role in the observed decline and mortality of sugar maple.

Abbreviations: CEC, cation exchange capacity • ECS, exchangeable cation sum