Formation of crown for Siberian cedar over a 12-year period after decapi-tation (suburban area of Krasnoyarsk)

Trees are decapitated to form a low-topped crown to improve cuttings and cone harvesting conditions. To do this, offer different methods of crowns decapi-tation with an intensity of 55-75%. The stimulating effect of pruning on the productivity of trees, the crowns growth, and the formation of multi-tops esti-mated. The plantations of Siberian cedar Pinus sibirica Du Tour are established to obtain valuable seeds and improve the environmental conditions in the subur-ban area of large industrial centers of Siberia. The Siberian cedar is distinguished not only by its high silvicultural characteristics, but also by the nutritional quali-ty of its pine "nuts". The aim of the research was to establish the peculiarities of crown formation for Siberian cedar on the plantation "Meteostation" over a 12-year period after decapitation. The plantation was established under the supervi-sion of R.N. Matveeva. Planting scheme 5 × 5 m applied. The object of the re-search was 54-year-old Siberian cedar grown from seeds harvested in 1964 in Leninogorsk Forestry of the Republic of Kazakhstan. The decapitation was per-formed for trees of 42 years old in 2005 at the height of 1.4-1.7 m. The height of the trees before decapitation varied from 3.3 to 4.5 m, the trunk diameter – from 9.5 to 23.6 cm. The average crown diameter was 3.8-4.3 m. The upper part of the crown is removed by 50.0-66.7%. The trees were measured for height, growth of the leading shoots replacing the central shoot, and trunk diameter at the soil sur-face. The level of variability was assessed according to S.A. Mamaev scale. By 2017, the trees had reached the height of 5.6-9.1 m; the number of leading shoots replacing the central one was 3-7. Trees with a trunk diameter of 12-18 cm had 3-4 leading shoots replacing the central one; those with a diameter of 20-26 cm had 6-7 shoots each. Linear growth of branches replacing the central shoot for the 12-year period was 4.0-7.6 m. The maximum growth was noted in tree 4-98: 7.0-90.0 % more than the others. Trees 4-33, 4-46, 4-73, 4-117 had the largest trunk diameter. It was found that the level of variability of tree height is low; growth, trunk diameter - medium, the number of leading shoots - high. The highest height (9.1 m) had the tree number 4-98, exceeding the others by 8.3-62.5 %. The aver-age number of lateral branches formed during the 5-year period on the leading shoots was compared. Between 2013 and 2017, the average growth was between 23.6 and 45.5 cm. The