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A. H. Johnson

Publications and source records attributed to A. H. Johnson.

5 recordsLinked to original sources
USGS1992

Aluminum in soil solutions from a subalpine spruce-fir forest at Whiteface Mountain, New York

Direct or indirect Al toxicity has been suggested as a principal factor in forest tree declines. We monitored ambient soil solutions in undisturbed and experimentally manipulated soils from a fir [ Abies balsamea (L.) Mill.]-spruce forest on Whiteface Mountain, NY, in order to characterize soil solution Al concentrations over a range of acid anion loadings. Under both natural and experimental conditions total Al and labile Al concentrations rarely exceeded values (180–250 µmol L −1 ) associated with reduced root growth in red spruce ( Picea rubens Sarg.). Over a 2-yr period ambient soil solutions averaged 76 and 46 µmol L −1 total Al in the organic and mineral horizons, respectively. The highest monthly mean concentrations occurred in winter. Disturbance-induced NO 3 accumulation and simulated acid rain applications produced higher peak Al values in experimental plots than were observed in undisturbed and untreated plots. Although soils of the fir-spruce zone exhibited the potential to yield solutions with phytotoxic Al concentrations, it appears that such concentrations are both spatially and temporally limited and infrequently present a direct stress to root growth in red spruce.

New York↗
USGS1992

Regional evaluations of acid deposition effects on forests: Eastern spruce-fir

Having reviewed the results of the Integrated Forest Study (IFS) project, we now try to place the results in a larger perspective by very briefly summarizing acid deposition effects and their potential role in forest health in the several forest types represented in the IFS project. This chapter gives brief overviews of the situation in eastern spruce-fir, eastern hardwood, and southern pine forests in North America; and a very brief overview of air pollution in arid forest ecosystems in Europe (with special emphasis on the situation in Norway where the single European IFS site was located). What follows in this chapter is by no means intended to be a comprehensive review of forest health and atmospheric deposition; such an analysis would require a volume of this size for each forest type and is well beyond the scope of this chapter. A comprehensive analysis of forest health and the role of atmospheric deposition has been published for Norway spruce in Europe (Schulze et al. 1989), and one is in preparation for red spruce (Eagar and Adams, in press); the reader is referred to those volumes for a far more detailed discussion than is possible here. The intent of this chapter is merely to highlight those aspects of forest health and atmospheric deposition that have bearing on, or that can be illuminated by, the IFS results.

Book chapter↗