Soil Carbon in Arid and Semiarid Forest Ecosystems

This chapter examines the arid-region forests that are characteristically ones in which annual water losses through evapotranspiration exceed or are slightly less than annual precipitation. The presence of water, interacting with soil processes, soil properties, soil biota, and vegetation ultimately determines the amount, quality, and state of carbon (C). The chapter describes the types of dry forests that occur in the Intermountain West of the United States, the soils that they occupy, the interactions with current and future land-management activities, and the potentials for additional C sequestration. The forest soils of the intermountain western United States are the most varied in the country because of their landscape settings, parent materials, climates, and biota. Forest soils in the Intermountain West have formed in the complete range of geologic parent material. The forests in the dry regions of the interior western United States are characteristically ones in which annual water losses through evapotranspiration exceed or are slightly less than annual precipitation.