Potential for carbon sequestration and the actual forest structure: the case of Krasnodar Krai in Russia

This work aims to analyze the age structure of forests in Krasnodar Krai in order to estimate their carbon sequestration potential. The research was conducted during 2015–2020 in 14 forested districts of Krasnodar Krai in the Russian Federation. A database of 96,000 sample plots was used. Aspen occupied the maximum area (20% of trees), while much smaller areas were occupied by linden, birch, pine, and oak (p≥0.05 with aspen). Spruce occupied three times smaller areas compared to aspen (p≤0.05), while maple, elm, ash, and alder had ten times smaller areas (p≤0.01). Among deciduous species by age, mature and overmature stands predominate, while in conifers a young growth prevails (44% – for pines). All pine forests belong to the 1st quality class (91%), for birch and aspen, it is 75–80% of trees (p≤0.05 with the frequency for pine), for spruce – 52% (p≤0.05), and for oak – 10% (p≤0.01). Different tree species make different contributions to carbon sequestration – from 0.3 tons per 1 ha (Alnus glutinosa) to 1.7 tons per ha (Fraxinus excelsior). Taking into account the areas occupied in the forest by different tree species, their contribution will also be different – from 0.5 thousand tons/1 year (F. excelsior) to 290 thousand tons per 1 year (Populus tremula). The total increase in wood stocks and carbon sequestration is mainly due to six forest tree species. The results obtained can be used to assess the potential for carbon sequestration in temperate forests, taking into account their different age structure and tree species composition.