Climate Trends and Average Increase in Aspen Forests’ Carbon Stock in Siberia According to Forest Inventory Data

Abstract

Aspen trees (Populus tremula L., 1753) are native to the boreal region of Siberia. These species’ fast growth and ability to regrow from root suckers mean carbon farms can be created using aspen trees for efficient atmospheric carbon sequestration. This paper presents the findings of research focusing on the dynamics of aspen forests’ growth and conditions in a changing climate according to forest inventories conducted in 1972, 1982, 2002 and partially 2021. The research was carried out in aspen stands growing in the Central Siberian subtaiga forest-steppe ecoregion. From 1982 to 2002, there was a steady trend towards increasing growing season temperature sum. At the same time, the amount of precipitation in the same season and period did not exceed the median value. With an increase in the temperature sum in 1982–2002 from 1800 °C to 2100 °C, the average forest carbon stock increased from 0.56 to 1.48 tonnes of carbon per hectare per year. This statement is true for pure aspen forests aged 10 to 30 years. A drastic decrease in the carbon sequestration potential was observed in aspen stands from the age of 40. After 55 years, the average increase in aspen forests’ carbon stock leveled off, and the differences became insignificant. Along with age-related increasing biomass growth rates in aspen forests, natural and pathological dieback led to reductions in resilience and wood loss. Aspen is characterized by rapid early growth rates, which allows aspen forests’ sequestration potential to be used to achieve effective carbon conservation.