Restorative dynamics of pine phytocenoses in clearcut areas in the floodplain terraces of the Moscow River

Abstract

Initial stages of restoration dynamics of phytocoenoses are of a special interest. Ecological conditions change crucially after timber harvesting. The exploration of two clearcut areas in the Moscow River valley in 3-5 years after felling allowed us to detect the direction of phytocoenosis dynamics. Scotch pine ( Pinus sylvestris L.) losses the competition with deciduous species in both sites constituting less than 50 % of regeneration. The largest number of individuals of Pinus sylvestris L. at the research sites, they have a three-year age: clear cut area No. 1 - 55 % and clear cut area No. 2 - 47 %. An intensive height increment of prevailing tree species was registered. In the site No. 1, an annual increase in height increment was registered indicating favourable growth conditions, while in the site No. 2, the 4-centimeter reduction of height increment was observed in the last year. The soil vegetation cover is an important ecological factor regulating the restoration dynamics of phytocoenoses on clearcut areas. To estimate the restoration dynamics of soil cover vegetation, 45 geobotanical descriptions were made. Totally 102 species of vascular plants referred to 72 genera were found on clearcut areas. The families with the highest frequency were Asteraceae - 12,7 %, Apiaceae - 10,8 %, and Poaceae - 8,8 %. A noticeable presence of Poaceae in the vegetation cover limits successful reforestation. The percentage of the most widespread ecologo-coenotic groups is 45% of the total number of registered species for meadow herbs, 16 % for tall herbs, 11 % for nemoral species, and 9% for forbs. Summary average projective coverage of herbage is 65-75 %. Under the conditions of reed-grass - herbal type of clearcut areas, Scotch pine is suppressed by both deciduous species and herbal vegetation, which makes the perspectives of its predomination in the future stand doubtful.