Радіальний приріст сосни звичайної у насадженнях Житомирського Полісся, в яких рубки догляду за лісом не проводять з часу аварії на ЧАЕС

The radial increment of Scotch pine in forest crops in the areas where proper forest management measures are carried out and where forestry activities were prohibited due to the significant levels of radioactive contamination of the territory was studied. The basic statistical characteristics of the tree-ring chronologies for determining the stability of plantations were calculated. For dendrochronological analysis, in each sample area, 15 samples (cores) of wood were selected at the height of the trunks of 1.3 m by the Presler drill. In the general tree-ring series, the average absolute width of the ring R(t) and its standard deviation DR(t) were determined. It is established that for average values of radial growth of plantations in all test areas there is a reliable difference of values (Ffact.=15.69>F(1;174;0,95)=3.90). Thus, the maximum width of the annual ring in the fresh bors of the SE "Malynske Forestry" an average of 4.21 mm, and the average width of the rings is about 1.50 mm; whereas in the SE "Narodytske Specialized Forestry" these figures are 2.52 mm and 1.16 mm, respectively. The maximum difference in the nature of the development of plantations is fixed from 1930 to 1982 (Ffact.=20.02>F(1;106;0,95)=3.93). Since 1983, the absolute increments in both forest managements under study have practically the same values. From 1987 to 1991, the radial increment of Scotch pine plantations in the SE "Malynske Forestry" and the SE "Narodytske Specialized Forestry" increased by 33 % and 18 % respectively. We can state that the pine cultures of fresh bors throughout the development period grow in diameter almost equally. The values of the sensitivity and variation coefficients give the important information on the development of forest plantations. Thus, the stress reactions in the pine plantations of the SE "Malynske Forestry" were also noticeable in the subsequent years 1932, 1946, 1998, 2012, 2016. However, in the SE "Narodytske Specialized Forestry" significant physiological stresses of the pine have been during the entire development cycle, but the maximum recorded in 1934, 1998, 2009, 2013, 2015 years. The results indicate to a certain difference in the development of pine trees on the "clean" territory and on the territory contaminated by radionuclides. Thus, it can be argued that the conduct of appropriate forest management measures affects the structural stability of pine trees and improves the sanitary condition of plantations in general.