ISSN: 0024-1148 RUSSIAN JOURNAL OF FOREST SCIENCE. 2016, No. 1, pp. 25-33

Received 31 March 2015

Dynamics of species diversity, projective cover, and phytomass of ground vegetation as well as the regeneration of pine was monitored during 4 years after N-fertilization with carbamide (100-400 kg N ha^-1 of primary nutrient) of middle-aged cowberry-herb-moss pine forest. We have found that carbamide application decreases the species diversity in grass-shrub story, plant species abundance of community, and projective cover of ground vegetation with amount of fertilizer. N-fertilization decreased the total phytomass of ground vegetation. Phytomass of grass-shrub story has been only 39% of the initial 4 years after the fertilization. Phytomass of mosses has doubled (from 24.7±6.4 to 48.5±5.7 g m^-2) 4 years after minimal fertilization (100 kg N ha^-1). However it remained unchanged at higher levels of fertilization (200-300 kg N ha^-1). Maximal fertilizer application has inhibited the growth of moss cover, with minimal phytomass of the story reached (19.8±2.8 g m^-2). Nitrogen fertilizer in amount of 100 kg N ha^-1  has stimulated natural regeneration of pine. The young growth amount after 4 years of carbamide application was 4000 ha^-1. Higher amounts of fertilizer have not had a significant effect on pine regeneration. We have found that N-fertilization is an effective method of assisted natural regeneration under the canopy of middle-aged pine stands on soddy-podzolic soils.

• Keywords: pine forest, lower vegetation story, ground vegetation, regeneration, carbamide, nitrogen fertilizer.

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