Defining soil organic carbon (SOC) quality and understanding the effects of vegetation cover and climate are of central importance to determining how stable SOC will be with changing climate and/or vegetation shifts.  Our earlier investigations at the TW Daniel Experimental Forest in Northern Utah have shown that SOC in forest and rangeland soils is qualitatively very different. The challenge is to determine whether and how differences in SOC that are ecologically meaningful and impact the function or behavior of SOC.  Using selected soil samples from conifer, aspen, sagebrush and meadow ecosystems, we compared several physical, chemical and biological SOC fractionation techniques to determine overlap in results and to identify those techniques that are both practical and ecological meaningful in defining SOC stability.