Assessment of Carbon Productivity Dynamics in Aspen Stands under Climate Change Based on Forest Inventories in Central Siberia

Abstract

The aim of the present research was to study the dynamics of growth and conditions of aspen stands under climate change, according to different periods of forest inventory. The study was conducted in modal aspen forests growing in the subtaiga/forest steppe region of Central Siberia. Aspen forests grow intensively at young age, which allows them to realize maximum carbon sequestration potential. The research was based on forest inventory data from 1972, 1982, 2002, and 2021 (the study was conducted on a limited territory). There was a steady increase in temperatures in the growing season from 1982 to 2002. The amount of precipitation in the same season and period, however, did not exceed the median value. With an increase in the sum of temperatures in 1982–2002 from 1800 °C to 2100 °C, carbon stored in the stands increased from 0.56 to 1.48 tons C/ha per year. This statement is true for pure aspen forests aged from 10 to 30 years. There is a certain (although indirect) influence that climate trends have on aspen forests’ carbon dynamics. There was a decrease in the average carbon increment in aspen forests from the age of 40. After 55 years, the average carbon increment values in the aspen forests leveled off, and the differences depending on the stand composition became insignificant. Along with an increase in biomass increment with age, aspen stands started losing resilience, and trees began to die due to natural and pathogenic mortality. At ages between 50 and 80, carbon emission increased from 1 to 12 tons C/ha.