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This article in SSSAJ

  1. Vol. 61 No. 3, p. 928-935
    Received: Apr 19, 1996

    * Corresponding author(s): jknoepp@lternet.edu
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Forest Management Effects on Surface Soil Carbon and Nitrogen

  1. Jennifer D. Knoepp  and
  2. Wayne T. Swank
  1. USDA Forest Service, Coweeta Hydrologic Laboratory, 3160 Coweeta Lab Road, Otto, NC



Changes in surface soil C and N can result from forest management practices and may provide an index of impacts on long-term site productivity. Soil C and N were measured over time for five watersheds in the southern Appalachians: two aggrading hardwood forests, one south- and one north-facing, undisturbed since the 1920s; a white pine (Pinus strobus L.) plantation planted in 1956; and two regenerating hardwood forests, a whole-tree harvest in 1980, and a commercial sawlog harvest in 1977. Soils on harvested watersheds were sampled before and for ≈15 yr after harvest. Surface soil C concentration on the undisturbed watersheds varied significantly among sample years. Concentrations fluctuated on the south-facing and decreased on the north-facing watershed. The pattern for total N was similar. Total N decreased significantly on the north-facing but was stable on the south-facing watershed. In the white pine plantation, C increased while N concentrations decreased during the 20-yr period. Soil C and N concentrations generally declined the first year following whole-tree harvest. Fourteen years after cutting, C remained stable, while N was greater compared with reference watershed soils. The commercial sawlog harvest resulted in large increases in surface soil C and N concentrations immediately after cutting. Carbon levels remained elevated 17 yr following cutting. Our data suggest that the forest management practices examined do not result in long-term decreases in soil C and N. However, the high interannual variation on all watersheds suggests that care must be taken in selecting control sites to determine long-term treatment impacts.

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