Forest soil characteristics in a chronosequence of harvested Douglas-fir forests

Griffiths, R.P. and Swanson, A.K.

Canadian Journal of Forest Research, Vol. 31 Issue 11 pp. 1871

2001

To assess the long-term effects of clearcutting on forest soils, microbiological and chemical soil characteristics were measured in a chronosequence of Douglas-fir (Pseudotsuga menziesii) stands in central Oregon. Old-growth stands had a lower denitrification potential and greater litter depth, forest-floor respiration rate, and concentration of ectomycorrhizal mats than 5-yr-old clearcuts. The soil characteristics of 15-yr-old stands were intermediate and those of 40-yr-old stands were similar to the ones found in old growth, although net primary productivity may not have recovered fully even 40 yr after clearcutting. No significant differences among stand ages were found for soil organic matter, soil moisture, pH, mineralizable N, laboratory soil respiration rate, or extractable ammonium. Climatic setting (low versus high elevation and north versus south aspect) did not appear to influence soil responses to clearcutting and subsequent recovery.