Abstract
The decomposition of litter occurs in several stages, the most intensive of which is the primary stage. The aim of this is identifying the features of the initial stage of needles’ decomposition in a cowberry pine forest and its dependence on hydrothermal conditions and internal biogeocenotic differences. The trial plot is located on the territory of the Kivach State Nature Reserve in the middle taiga subzone of the Republic of Karelia. Decomposition of needles was carried out by laying bags with needles. The study of the features of decomposition of needles in different microgroups of ground vegetation during the first vegetation period showed insignificant differences within the standard deviation. It was found that the decomposition of needles in the cowberry pine forest in the middle taiga subzone reached 31.5 ± 3.5% during the vegetation period (120 days), 44.0 ± 1.4% during the annual cycle and 55.8 ± 5.1% during a two-year period. The use of the asymptotic model of Berg and Ekbohm showed an overestimation of the annual decomposition value by 10–3%. The proposed logarithmic model is based on two-year empirical data and gives an error of 3–5% in calculating the annual loss of needle mass.