SOME FEATURES OF FORMATION OF ANNUAL RING AND STRAIGHT – AND WAVE-GRAINED BASIC DENSITY WOOD OF ABIES ALBA MILL.

In the Bukovynski Carpathians, the natural area of silver fir is defined by climatic conditions and soil fertilize, and is ranged from 300 to 1200 m asl. Forest stands is characterized by the highest volumetric productivity in the biotopes at the altitude of 500-900 m asl. The total area of fir forest types in Chernivtsi region is 49.14 thousand hectares (20.1 %). The ultimate purpose of the work is to study the number of annual rings per 1 cm and the basic wood density within the radius and the stem height of Abies alba Mill. with straight- and wavy-grained wood. The research covered a mature forest stands of 105 year-old silver fir. The composition of the forest stand constituted 60 % of silver fir, 30 % of European beech and 10 % of Norway spruce that were grown in the wet conditions of the forest district Lopushna of Berehomet FE with latitude of 48о06ʹ02.34ʺ N, longitude of 25о13ʹ02.46ʺ E and altitude of 985 m asl. To study the differences in the macrostructure and basic density of wood six model trees with wave- and straight-grained structure were harvested. Wood samples of 0.6 m in length at the height of 1.3 m and 7 m were cut from each model tree (log). Research results have shown that the macrostructure index increased evenly in the direction from pith to bark. The maximum values of the number of annual rings per 1 cm characterised the mature wood of silver fir in the last 30-40 year of the growth. Within the tree height of silver fir with straight-grained wood, the tendency of the increasing the macrostructure index remained. The number of annual rings in the stem with wavy-grained wood decreased in diameter indicating an increase in the annual growth in the last 20-30 years of the growth. The number of annual rings per 1 cm of silver fir with straight-grained wood ranged from 5.0 to 15.0 pcs.∙cm-1 with an average value of 8.8 pcs.∙cm-1 at the breast height and 8.1 pcs.∙cm-1 at the height of 7.0 m. The basic density of the wavy-grained wood varied from 292 to 478 kg∙m-3, while the basic density of the straight-grained wood ranged from 256 to 408 kg∙m-3. The revealed wood-science aspects of the formation of anomaly of silver fir wood need further anatomical and physical-mechanical research.