Biophysical Controls on Soil Respiration in the Dominant Patch Types of an Old-Growth, Mixed-Conifer Forest
Authors: Ma, Siyan1; Chen, Jiquan2; Butnor, John R.3; North, Malcolm4; Euskirchen, Eugénie S.5; Oakley, Brian6
Source: Forest Science, Volume 51, Number 3, June 2005 , pp. 221-232(12)
Abstract:
Little is known about biophysical controls on soil respiration in California's Sierra Nevada old-growth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly among the patch types, ranging from 2.0 to 4.5 µmol m-2 s-1 and from 0.9 to 2.9 µmol m-2 s-1 during the 1999 and 2000 measuring periods, respectively, with the maximum in CECO and the minimum in OC. Multiple peaks of seasonal SRR were functions of soil temperature and moisture dynamics. The relationship between SRR and soil temperature switched from a positive to a negative correlation when soil moisture dropped from saturation to drought. Time lag, as a function of soil moisture, was included in an exponential model to assess the effects of soil moisture on SRR in this seasonal water-stressed ecosystem. The total soil C flux summed by an area-weighted average across all three patch types was 660 ± 163 g C m-2 from May to Oct. 2000. These results may be applicable to other water-stressed forests in the Mediterranean climate zone, and have implications for the conservation of soil carbon. FOR. SCI. 51(3):221–232.Keywords: Soil CO2 efflux; soil temperature; soil moisture; Sierra Nevada; California; environmental management; forest; forest management; forest resources; forestry; forestry research; forestry science; natural resources; natural resource management
Document Type: Regular article
Affiliations: 1: Ecosystem Science Division, ESPM University of California at Berkeley 151 Hilgard Hall Berkeley CA 94720-3110 Phone: (510) 642-2421;, Fax: (510) 543-5098, Email: sma@nature.berkeley.edu 2: Department of Earth, Ecological, and Environmental Sciences University of Toledo 2801 West Bancroft Street Toledo OH 43606, Email: jiquan.chen@utoledo.edu 3: Southern Research Station USDA Forest Service 3041 Cornwallis Road Research Triangle Park NC 27709, Email: jbutnor@fs.fed.us 4: Sierra Nevada Research Center, Department of Environmental Horticulture University of California at Davis Davis CA 95616, Email: mpnorth@ucdavis.edu 5: Institute of Arctic Biology University of Alaska Fairbanks Fairbanks AK 99775, Email: ffese@uaf.edu 6: College of Forest Resources University of Washington Seattle WA 98195, Email: boakley@u.washington.edu
