Comparison of Carbon Accumulation in Douglas Fir and Red Alder Forests

Soil organic carbon (C) or organic matter has been studied under various plant communities. In comparisons of similar soils having grassland or forest vegetation, surface horizons of the forest soil may have lower levels of soil C. The chapter compares organic matter production and storage in adjacent stands of mature alder and Douglas fir. The research was conducted in adjacent stands of red alder and Douglas fir at the Thompson Research Center, Cedar River Watershed, Washington. This site is located 56 km southeast of Seattle at 220 m elevation in the foothills of the Cascade Mountains. The difference in total C storage is a result of higher accumulation of C in the 0 horizon and mineral soil profile of the alder stand, which more than offsets the higher C content of the Douglas fir vegetation. A striking difference in growth rates was observed when alder and Douglas fir were replanted on the conversion plots.