TY - JOUR
T1 - What the soil reveals
T2 - Potential total ecosystem C stores of the Pacific Northwest region, USA
AU - Homann, Peter S.
AU - Harmon, Mark
AU - Remillard, Suzanne
AU - Smithwick, Erica A.H.
N1 - Funding Information:
This research was made possible by funding from the following sources: H.J. Andrews Long Term Ecological Research (LTER) program, under NSF grant number DEB-9632921; NASA grant NAG5-6242; Pacific Northwest Research Station Long-Term Ecosystem Productivity Program, Corvallis, OR; Interagency Agreement DW 12936179 between USEPA and the Pacific Northwest Research Station; Natural Resources Conservation Service agreement 68-7482-7-310; Stand Management Cooperative, University of Washington; Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture under Agreement No. 95-37107-1642. We thank Jerry Franklin and Steve Acker for old-growth plot establishment and oversight; and Jason Kapchinske, Andy Boyce, Duane Bays, Bob Gonyea, and Bert Hasselberg for technical support.
PY - 2005/12/10
Y1 - 2005/12/10
N2 - How much organic C can a region naturally store in its ecosystems? How can this be determined, when land management has altered the vegetation of the landscape substantially? The answers may lie in the soil: this study synthesized the spatial distribution of soil properties derived from the state soils geographic database with empirical measurements of old-growth forest ecosystem C to yield a regional distribution of potential maximum total-ecosystem organic C stores. The region under consideration is 179,000 square kilometers extending from the southern Oregon border to the northern Washington border, and from the Pacific Ocean to the east side of the Cascade Mountains. Total ecosystem organic C (TEC) was measured in 16 diverse old-growth forests encompassing 35 stands and 79 pedons to a depth of 100 cm. The TEC ranged between 185 and 1200 Mg C ha-1. On an average, 63% of TEC was in the vegetation, 13% in woody detritus, 3% in the forest floor, 7% in the 0-20 cm mineral soil, and 13% in 20-100 cm mineral soil. The TEC was strongly related to soil organic C (SOC) in the 0-20 cm mineral soil, yielding a monotonically increasing, curvilinear relation. To apply this relation to estimate the TEC distribution throughout the region, 211 map units of the state soils geographic database (STATSGO) were used. The SOC in the 0-20 cm mineral soil of the map units was consistent with values from previously measured pedons distributed throughout the region. Resampling of 13 second-growth forests 25 years after initial sampling indicated no regional change in mineral SOC, and supported the use of a static state soils map. The SOC spatial distribution combined with the quantitative old-growth TEC-SOC relation yielded an estimate of potential TEC storage throughout the region under the hypothetical condition of old-growth forest coverage. The area-weighted TEC was 760 Mg C ha-1. This is ∼100 Mg C ha-1 more than a previous estimate based on a coarser resolution of six physiographic provinces, and ∼400 Mg C ha-1 more than current regional stores. The map of potential TEC may be useful in forecasting regional C dynamics and in land-management decisions related to C sequestration.
AB - How much organic C can a region naturally store in its ecosystems? How can this be determined, when land management has altered the vegetation of the landscape substantially? The answers may lie in the soil: this study synthesized the spatial distribution of soil properties derived from the state soils geographic database with empirical measurements of old-growth forest ecosystem C to yield a regional distribution of potential maximum total-ecosystem organic C stores. The region under consideration is 179,000 square kilometers extending from the southern Oregon border to the northern Washington border, and from the Pacific Ocean to the east side of the Cascade Mountains. Total ecosystem organic C (TEC) was measured in 16 diverse old-growth forests encompassing 35 stands and 79 pedons to a depth of 100 cm. The TEC ranged between 185 and 1200 Mg C ha-1. On an average, 63% of TEC was in the vegetation, 13% in woody detritus, 3% in the forest floor, 7% in the 0-20 cm mineral soil, and 13% in 20-100 cm mineral soil. The TEC was strongly related to soil organic C (SOC) in the 0-20 cm mineral soil, yielding a monotonically increasing, curvilinear relation. To apply this relation to estimate the TEC distribution throughout the region, 211 map units of the state soils geographic database (STATSGO) were used. The SOC in the 0-20 cm mineral soil of the map units was consistent with values from previously measured pedons distributed throughout the region. Resampling of 13 second-growth forests 25 years after initial sampling indicated no regional change in mineral SOC, and supported the use of a static state soils map. The SOC spatial distribution combined with the quantitative old-growth TEC-SOC relation yielded an estimate of potential TEC storage throughout the region under the hypothetical condition of old-growth forest coverage. The area-weighted TEC was 760 Mg C ha-1. This is ∼100 Mg C ha-1 more than a previous estimate based on a coarser resolution of six physiographic provinces, and ∼400 Mg C ha-1 more than current regional stores. The map of potential TEC may be useful in forecasting regional C dynamics and in land-management decisions related to C sequestration.
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U2 - 10.1016/j.foreco.2005.08.035
DO - 10.1016/j.foreco.2005.08.035
M3 - Article
AN - SCOPUS:27144464870
SN - 0378-1127
VL - 220
SP - 270
EP - 283
JO - Forest Ecology and Management
JF - Forest Ecology and Management
IS - 1-3
ER -