ABSTRACT
This chapter uses a simple model to generalize a few soil carbon processes and examines assumptions concerning their interrelationships. The model used is a conceptual carbon allocation model published by Ruark and Blake. Ruark and Blake's model is parameterized to reflect conditions in a slash pine ecosystem using published data from Gholz for comparison to model outputs. Pinyon-juniper (PJ) ecosystems are extensive in the western United States, and are markedly different, ecologically, from the slash pine systems of the southeastern United States. PJ systems are considered semi-arid woodlands and can occur at elevations from about 90 to above 2200 m in rainfall zones averaging about 200 to over 500 mm annually. McDaniel and Graham provided data on soil organic carbon distribution both under the canopy and in the interspace for two PJ stands in Utah. The organic carbon distribution under the canopy appeared typical of most forested soils. It was concentrated near the surface and decreased with depth.
