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Nutrient cycling by throughfall and stemflow precipitation in three coastal Oregon forest types

Journal Article · · U.S., For. Serv., Res. Pap. PNW; (United States)
OSTI ID:5464213

The role of precipitation in N-cycling in three coastal Oregon forest types appears to be minor in comparison with the much greater amounts of N cycled in litterfall. Concentration of NO/sub 2//sup -/ was much greater in stemflow from conifers than in other precipitation-forest type combinations, and that of NH/sub 4//sup +/ was substantially greater in alder stemflow and throughfall. These observations indicate the need for more information on microbial populations on leaf and needle surfaces and on tree stems to elucidate possible differences between tree species in numbers of nitrifying and ammonifying bacteria. Substantial differences between forest types in amount of dissolved solid in precipitation indicate that other nutrient elements might be more important subjects of investigation than N. The role of different tree species in influencing throughfall and stemflow content of exchangeable bases, especially, appears to require further investigation. Other factors that appear to require study include metabolites such as carbohydrates, amino acids, and organic acids in general. Despite the generally greater content of nutrient ions in stemflow than in throughfall, stemflow appears to be of little importance in nutrient cycling by precipitation because of the small volume of stemflow on an area basis. In future studies of ionic content of precipitation in coastal Oregon forests, sampling effort might better be concentrated on throughfall. Likewise, determination of NO/sub 2//sup -/ -N is not necessary because of its extremely rare occurrence in measurable amounts. Acidity of throughfall precipitation was not different from that of open-collected rainfall. Stemflow was always more acid than the other two forms of precipitation, but the ecological significance of this difference is not believed to be great.

OSTI ID:
5464213
Journal Information:
U.S., For. Serv., Res. Pap. PNW; (United States), Journal Name: U.S., For. Serv., Res. Pap. PNW; (United States) Vol. PNW-54; ISSN XPFNA
Country of Publication:
United States
Language:
English