Publication Date:
2004-03-01
Description:
The red spruce (Picea rubens Sarg.) Fraser fir (Abies fraseri (Pursh) Poir.) forest of the southern Appalachians contains a significant amount of coarse woody debris (CWD) that may affect the nitrogen (N) export signal in streams originating from this N-saturated system. Interpretation of the N sink versus source status of CWD of red spruce and Fraser fir was dependent on the method used. Over a chronosequence of decay, (1) N concentrations suggested a N sink (i.e., a net gain of N of 923% in red spruce and 563% in Fraser fir relative to N in live trees); (2) N contents that reflected changes in density suggested a smaller N sink (i.e., a net gain of N of 218% in red spruce and 125% in Fraser fir relative to N in live trees), but the stoichiometry of N and C suggested a N source in early stages of decay and a N source in the most advanced stage of decay only; and (3) N contents that reflected changes in volume suggested a N source (i.e., a net N loss of 172% in red spruce and 122% in Fraser fir). The C/N ratios in CWD suggested that the shift from a N source to a N sink represented a shift from the mobilization of dissolved organic N to the immobilization of ammonium N and (or) nitrate N. The magnitude of the net change in N contents in both red spruce and Fraser fir was amongst the highest reported in literature, suggesting that CWD plays a particularly important role in N dynamics in N saturated forests.
Print ISSN:
0045-5067
Electronic ISSN:
1208-6037
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
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