Clear-cutting and the nitrogen cycle

• Published in: Ecological bulletins no. 33; pp. 631 - 642
• Main Author: Vitousek, P.M. (North Carolina Univ., Chapel Hill (USA). Dept. of Botany)
• Format: Journal Article
• Language: English
• Published: Stockholm (Sweden) NFR 1981; Swedish Natural Science Research Council
• Subjects: MANAGEMENT IMPACTS
• ISBN: 9789154602902; 9154602904
• ISSN: 0346-6868

Nitrogen mineralization and immobilization are increased immediately after clear-cutting, while plant nitrogen uptake is reduced. In fertile sites, the interaction of these processes leads to an excess of nitrogen mineralized over nitrogen utilized within the forest. Where nitrification is rapid, this additional available nitrogen can be lost by leaching or denitrification; where it is slow, ammonium accumulates in the soil or is volatilized as ammonia. In less fertile sites, especially in coniferous forets, the nitrogen mineralized after cutting can all be immobilized within the forest. Whole-tree harvesting techniques decrease nitrogen immobilization and so increase the amount of excess nitrogen mineralized. Many ecosystem-level studies of clear-cutting effects on nitrogen cycling have been published, but the diversity of site characteristics and cutting methods included makes it difficult to generalize about the overall effects of clear-cutting. Additional ecosystem-level studies of clear-cutting effects would be less valuable than the development of a process-level understanding of the effects of clear-cutting on the nitrogen cycle.