Interaction of Temperature, Moisture, and Soil Chemistry in Controlling Nutrient Cycling and Ecosystem Development in the Taiga of Alaska

Abstract

Dominating all aspects of forest ecosystem structure and function in the Alaskan taiga is the cold environment. Low mean annual temperature (-3.5°C) and a short growing season (90–100 days) result in a restricted period during which biological activity may occur in these forests. Low soil temperature restricts chemical weathering, organic matter mineralization, and soil profile development. Permafrost occurs in those soils with average annual temperatures of -1°C or less. Thus, inceptisols, entisols, and histosols occupy 78%, 12%, and 7%, respectively, of the land area or 97% of approximately 33,000,000 ha of interior Alaska. More intensively developed soils, including mollisols and spodosols, encompass only 3% (approximately 840,000 ha). The semiarid nature of the environment (29.4 cm mean annual precipitation, potential evapotranspiration [PET] approximately 45 cm) (Patric and Black 1968) further dictates that water will be limited to chemical and biological processes, and movement of solution through the soil will be markedly restricted compared with these conditions in many temperate latitude forest environments.