ABSTRACT Background: In spite of important functions the ground vegetation performs, the research on global change and human impact on forests has traditionally focused on tree layer. We have analyzed the influence of clear-cuttings on ground vegetation biomass (GVB), fractional structure and annual increment of dwarf shrubs (bilberry and cowberry) shoots. The investigation was carried out at clear-cut areas of the Scots pine forests in the European North-East of Russia. Results: The GVB value after clear-cutting increased by 1.9−2.4 times. The GVB values at particular technological elements of clear-cuts (apiaries, skidding tracks) were obtained. On skidding tracks, the biomass was by 1.2-1.7 time less than that on apiaries. Among individual species, Vaccinium vitis-idaea L., Pleurozium schreberi (Willd. ex Brid.) and Dicranum polysetum Sw. demonstrated a positive reaction to clear-cutting but mosses of the Sphagnum L. genus reacted negatively. Invasion of Epilobium angustifolium L. and Avenella flexuosa (L.) Drejer increased the grass biomass, especially on skidding tracks. The linear model was applied for describing the relationship between above- and underground dwarf shrub biomass. The clear-cutting had a negative effect on shoot age and mass of both bilberry and cowberry. However, comfortable light conditions raised the role of foliage in biomass and heightened the increments of studied dwarf shrubs by 1.2-1.3 time. Conclusion: Clear-cutting had a positive effect both on GVB and increment of dwarf shrubs in Scots pine forests on the European North-East.

ABSTRACT Background: Forests are the main terrestrial regulators of greenhouse gas concentrations. However, estimates of carbon fluxes in them are characterized by large uncertainties. Therefore, the derivation of predictors for their assessment is an urgent task. The aim was to assess the carbon stocks in the biomass to characterize the intensity of aboveground net production and the amount of litterfall in Scots pine forests of different types on the North-East of the Europe. We estimated biomass and aboveground net primary production (ANPP) of stands using sample trees. For vegetation of ground cover biomass and primary production evaluating, we cut off all aboveground organs on an area of 625 cm2 and removed the first-year parts. Litterfall was collected over 3-6 years using litter traps. Results: Most of the carbon in the biomass of pine forests is concentrated in trees (Cstand) with dominating role of stem wood. However, in boggy forests, ground vegetation plays a significant role in carbon stocks, both in absolute and relative values. We estimated carbon fluxes in ANPP and stand litterfall. High contribution of needles was detected for these flows. The ratio between ANPP and Cstand varied from 0.018 to 0.056 but between Litterfal and Cstand ranged from 0.008 to 0.024. Conclusion: The biomass, ANPP and litterfall depended form forest type. Obtained ratios between them can be used for assessing carbon fluxes in large regions using remote data collection of forest biomass.