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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Fenn, M. E. Articles by Dunn, P. H. Search for Related Content PubMed Articles by Fenn, M. E. Articles by Dunn, P. H. Agricola Articles by Fenn, M. E. Articles by Dunn, P. H.

Litter Decomposition Across an Air-Pollution Gradient in the San Bernardino Mountains

Pacific Southwest Forest and Range Exp. Stn., USDA-FS, Forest Fire Lab., 4955 Canyon Crest Drive, Riverside, CA 92507

*Corresponding author.

ABSTRACT

Air pollution may affect forest ecosystems by altering nutrient cycling rates. The objective of this study was to compare decomposition rates of L-layer litter of ponderosa pine (Pinus ponderosa Laws.) and Jeffrey pine (Pinus jeffreyi Grev. & Balf.) collected from across an air-pollution gradient in the San Bernardino Mountains in southern California. Litter from the more polluted western areas decomposed at a significantly (P = 0.01) faster rate than litter from plots in areas exposed to moderate or low pollution levels. The Shannon diversity index values for litter fungi were 1.41, 1.84, and 2.25 for plots in areas exposed to low, moderate, and high pollution levels. Nitrogen content of litter was greatest in the high pollution plots and was positively correlated with litter decomposition rate. Higher N and lower Ca content of litter at the more polluted western sites suggest that litter in the western plots originates from younger foliage than litter at the less polluted sites, possibly because of ozone (O₃)-induced needle abscission. Possible factors contributing to increased decomposition and fungal diversity in the western plots include: higher litter nutrient content because litter originates from younger foliage, higher soil N levels which may result in higher foliar N content, greater input of N from air pollution, and O₃ damage to needles creating favorable sites for microbial decomposers.

Received for publication October 17, 1988.