Forest carbon stock in Left-bank Forest-Steppe of Ukraine according to intensive forest monitoring data

Abstract

The issues of carbon stock and dynamic in different carbon pools in forest stands of Left-bank Forest-steppe of Ukraine are considered. The aim of the study was to evaluate carbon stocks and their changes in main pools: trees biomass and mortmass. Data of two repeated observations on 19 permanent intensive forest monitoring plots in Kharkiv and Sumy regions were used. Conversion method was used. Study of increment and mortality dynamics at monitoring plots showed, that two processes impact carbon balance: biotic damage which leads to trees dieback, and partial removal of dead wood from stands. Oak stands have, on average, higher carbon stock in trees biomass and mortmass (102.9 t С ha-1) than the pine stands (98.7 t С ha-1), which is associated with a higher representation of mature and overmature oak stands. While comparison by age classes showed that pine stands, in general, have higher values of C in trees biomass, due to higher productivity. The increase in carbon stocks with age is observed. The annual change of C stock in trees biomass is the highest in younger stands, and it decreases with age; while in mortmass it increases. Mature and overmature oak stands have negative trees biomass and positive dead wood growth. At age 81-100 years oak forest stands have higher carbon storage capacity than pine (total carbon stock in main pools (biomass, mortmass, litter and soils (30-cm layer)) is 191.7 t C ha-1 for oak and 175.4 t C ha-1 for pine stands). Trees biomass carbon prevails among other pools (50.3 % in oak forests, and 57.6% in pine), the next is soil carbon pool (45.9 and 29.0%, respectively). National forest inventory will provide data for assessments of carbon stocks and dynamics in trees biomass and mortmass pools. However, forest soil monitoring is necessary to evaluate carbon pools in soils and litter.