QUALITY OF TREE LITTER AS AN INFORMATIVE INDICATOR OF FUNCTIONAL CLASSIFICATION OF FORESTS

Abstract

Relevance and goals. In the context of global climate change, the climate-regulating function of forests deserves special attention. There is still no functional classification of forests according to the effectiveness of carbon accumulation function. The aim of this paper is to discuss an approach to such classification based on the assessment of tree litter quality. Objects and methods. To test the approach to the identification of functional types of forests based on the quality of tree litter, taking into account the location in the geochemically linked landscape and the mechanical composition of soil-forming rocks, data on soils and vegetation obtained at 23 testing sites in the subzone of coniferous-broadleaf forests of the European part of Russia on the territory of Bryansk Polesie and Moskvoretsko-Okskaya plain were used. For indirect (Landolt’s ecological scales using the SpeDiv program) assessment of differences in the soil richness in forests belonging to different functional types, the species composition at 160 geobotanical plots in forest sites in the Moscow, Bryansk, Smolensk, Kostroma Regions, Krasnodar Territory, and the Republic of Adygea (Northwestern Caucasus) were analyzed. Results. Examples of functional forest types for coniferous — broad-leaved forests of the European part of Russia are given. The differences in soil carbon stock between forests belonging to different functional types were found, and a preliminary assessment of the influence of the location in the geochemically linked landscape and the mechanical composition of soils on the accumulation of carbon in soils in the same functional forest types is given. Conclusion. Based on the quality of the tree litter, 15 functional forest types were identified, which are confirmed by examples of forests in the subzone of coniferous-broad-leaved forests of the European part of Russia and in the belt of coniferous-broad-leaved forests of the Northwestern Caucasus. The validity of identification of functional forest types for the efficiency of carbon accumulation in soils based on the quality of tree litter, taking into account the influence of “external factors” (the location of forests in the geochemically linked landscape and the mechanical composition of soil-forming rocks), was confirmed by data obtained at 23 sites. Using this approach allowed us to reveal differences in the soil carbon stock and related characteristics of soil fertility estimated on an ecological scale between the functional forest types, identified on the base of tree litter in the mixed, coniferous-broad-leaved forests at the same location in the geochemically linked landscape. Differences in soil carbon stocks in forest ecosystems of the same functional forest types formed on clay loam and sandy loam soil-forming rocks were also revealed. Differences in soil carbon stocks in forests belonging to the same functional type, but formed at different locations in the geochemically linked landscape, have been confirmed: soil carbon stocks were higher in forests at the transit landscapes compared to those in autonomous ones.

Keywords

• coniferous-broad-leaved forests
• forest functional classification
• functional types of forests
• carbon stocks