Balsam poplar radial growth in Arkhangelsk
Widespread planting of poplar in Arkhangelsk, allowed us to study its radial growth in different growth conditions. In ordinary radial growth of poplar plantations as compared with squares. The highest intensity of growth in diameter is noted under the age of 15 years in the ordinary crop and up to 10 years in the plantation. After 50 years of growth in diameter stabilized at 2 mm per year. Therefore, radial increment of 2 mm can be an indicator of old age in poplar. Dependence of the radial increment of age period described by the equation of the parabola 2 order: y = 0,001 x <sup>2</sup> - 0,135 x + 7,241 (R <sup>2</sup> = 0,906). Diameter 50 cm in ordinary crop indicates the age of 50 years old. In ordinary poplar plantations diameter dependence on the age described by the equation y = -0.010 x <sup>2</sup> + 1.544 x - 2.816 (R <sup>2</sup> = 0.997); in squares: y = -0.009 x <sup>2</sup> + 1.269x - 1.669 (R <sup>2</sup> = 0.987).