The use of unmanned aerial vehicles to assess young trees formation in clean cutting areas

The article presents information on the use of an unmanned aerial vehicle to assess young trees state in seed blocks. An unmanned aircraft complex of an airplane type was used to obtain aerial photographs. Aerial photography was carried out in the visible range (RGB) and the visible and near infrared ranges (RED, REG, GRE, NIR). The spatial resolution in the visible range was less than 5 cm, in the visible and near infrared - 19 cm. The use of an unmanned aerial vehicle and multispectral images allowed assessing the condition and structure of young trees at the cutting of 8 years ago with the created forest crops of scots pine. On the orthophotoplane, rows of forest crops and admixtures of coniferous and deciduous species of natural origin are clearly visible both in the rows and in the inter-row spacing. The compositions of the young trees formed on the experimental plots and that of the stands in the seed blocks were determined. The Scotch pine was deciphered by the rounded shape and relatively uniform, fine-grained texture of the crown projection, as well as the shadow in the form of a crescent or half-ring, which is due to the spherical or paraboloid shape of the crown with a rounded top. Spruce was deciphered by a star-shaped crown projection pattern and a shadow in the form of a semicircle and a triangle, which is due to the cone-shaped shape of the crown. Multispectral image analysis allowed identifying the European spruce by its greenish-blue color. Deciduous trees in multispectral images had yellow-green, yellow-orange, reddish shade of crown projections. The image of the warty birch was characterized by the rounded shape of the crown projection with an uneven edge, medium-grained or lumpy texture due to the distribution of shaded and illuminated areas in the crown of the tree. Due to the high spatial resolution of images from an unmanned aerial vehicle on inclined projections of trees in the visible range, the birch was noticeable by the white color of the trunk. Using special programs, the number of trees by species was determined, and even so the biometric characteristics of individual plants. It is advisable to use the obtained materials in the development of regulatory documents and planning of forestry work.