Forest Biogeochemistry and Drought

Abstract

Soil moisture is a critical regulator of C, water, and nutrients flowing through forests (Kozlowski 1982; Aber et al. 1995; Granier et al. 1999; Kljun et al. 2007; Nepstad et al. 2007; Penuelas et al. 2007; Welp et al. 2007; Johnson et al. 2008; Borken and Matzner 2009), and shortages of moisture thus can have a dramatic influence on forest function and the relationship between forests and surrounding ecosystems and the atmosphere. Drought – defined here as an absence of precipitation sufficient in duration to induce injury to plants – occurs in nearly all forests (Hanson and Weltzin 2000). Although predictions of altered precipitation patterns with climate change typically reflect greater uncertainty than those of future temperature, many climate models forecast longer periods of soil moisture deficit in multiple forested regions of the globe (IPCC 2007). Thus, drought, already identified as an important disturbance in forests (Foster et al. 1997; McDowell et al. 2008), will likely become more frequent with climate change and a more important perturbation to forest biogeochemical cycling in many regions.