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United States Department of Agriculture

Agricultural Research Service

Title: Influence of Forest Age on Forms of Carbon in Douglas-Fir Soils in the Oregon Coast Range

Authors
item Entry, James
item Emmingham, William - OREGON STATE UNIVERSITY

Submitted to: Canadian Journal of Forest Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 1997
Publication Date: N/A

Interpretive Summary: The amount and type of carbon C in a forest soil reflects the past balance between C accumulation and loss. In an old-growth forest soil, C is thought to be in dynamic equilibrium between accumulations and losses. Disturbance upsets this equilibrium by altering the microclimate, the amount and type of vegetation growing on a site and properties that affect organic matter decomposition. We measured total C and forms of soil C in the L, F and H layers and in the light fraction of soil organic matter in the 0-10 cm of mineral soil in old-, second- and young-growth Douglas-fir soils in the Oregon Coast Range. Total C in L, F and H layers and in organic material in the top 10 cm of mineral soil in old-growth forests was higher than in young- or second-growth forests. Old-growth forests had a higher lignin concentration and lower concentrations of sugar, hemicellulose, and cellulose in the L, F and H layers and in the light fraction of organic material than second- or young-growth forests. Old-growth forests had greater amounts of FWO, sugar, cellulose and lignin, in the L, F and H layers ha/2 and greater amounts of hemicellulose, cellulose and lignin in the light fraction of organic matter in the 0-10 cm of mineral soil ha/2 than young- and second- growth forests. Concentrations of fats, waxes, and oils (FWO), sugar and tannin in the light fraction of organic matter in the 0-10 cm of mineral soil did not differ with forest age.

Technical Abstract: The amount and type of carbon C in a forest soil reflects the past balance between C accumulation and loss. In an old-growth forest soil, C is thought to be in dynamic equilibrium between accumulations and losses. Disturbance upsets this equilibrium by altering the microclimate, the amount and type of vegetation growing on a site and properties that affect organic matter decomposition. We measured total C and forms of soil C in the L, F and H layers and in the light fraction of soil organic matter in the 0-10 cm of mineral soil in old-, second- and young-growth Douglas-fir soils in the Oregon Coast Range. Total C in L, F and H layers and in organic material in the top 10 cm of mineral soil in old-growth forests was higher than in young- or second-growth forests. Old-growth forests had a higher lignin concentration and lower concentrations of sugar, hemicellulose, and cellulose in the L, F and H layers and in the light fraction of organic material than second- or young-growth forests. Old-growth forests had greater amounts of FWO, sugar, cellulose and lignin, in the L, F and H layers ha/2 and greater amounts of hemicellulose, cellulose and lignin in the light fraction of organic matter in the 0-10 cm of mineral soil ha/2 than young- and second- growth forests. Concentrations of fats, waxes, and oils (FWO), sugar and tannin in the light fraction of organic matter in the 0-10 cm of mineral soil did not differ with forest age.

Last Modified: 7/28/2014
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