Comparison of Douglas Fir and Red Alder Soil and Site Carbon Accumulation

Soil organic C or organic matter has been studied under various plant communities. In comparisons of similar soils having either grassland or forest vegetation, surface horizons of the forest soil may have lower levels of soil C (Ugolini and Schlichte, 1973; Almendinger, 1990) or higher levels (Jenny, 1980). Even between forest types, soil C may vary. Alban (1982) found the forest floor in a Populus tremuloides stand had 1040% less organic matter than in Picea glauca, Pinus resinosa or Pinus banksiana stands of the same age. Suface soil (0-5 inches) in a Picea abies forest had a significantly higher concentration of organic matter than did the soil from Quercus rubra or Pinus strobus (Challinor, 1968). In comparisons of Pinus radiata and eucalyptus forests in Australia, Turner and Kelly (1985) found higher concentrations of C in the surface mineral soil of one pine plantation at only one of two sites. In another P. radiata eucalyptus comparison, Turner and Lambert (1988) found greater soil C in a pine plantation in a low-fertility site, but less soil C in a high-fertility site.