The Sensitivity of Ecosystem CO2 Flux in the Boreal Forests of Interior Alaska to Climatic Parameters,

An ecophysiological model of carbon uptake and release was used to examine C02 fluxes in 17 mature forests near Fairbanks, Alaska. Under extant climatic conditions, ecosystem C02 flux ranged from a loss of 212 g C02 m-2 yr-1 in a black spruce stand to an uptake of 2882 g C02 m-2 yr-1 in a birch stand. Increased air temperature resulted in substantial soil warming. Without concomitant increases in nutrient availability, large climatic warming reduced ecosystem C02 uptake in all forests. Deciduous and white spruce stands were still a sink for C02, but black spruce stands became, on average, a net source Of CO2- With increased nutrient availability that might accompany soil warming, enhanced tree growth increased C02 uptake in conifer stands.