ABSTRACT Forest stand density and spatial distribution are fundamental determinants of ecosystem structure and productivity; however, their dynamics in artificially established biogroup plantations in the South Caucasus remain insufficiently studied. This study investigates the structural characteristics of forest phytocoenoses established using the biogroup method in the Zangilan district of the Eastern Zangezur region during the 2024–2025 field research period. Three sample plots (each 1 ha) were established, and the forest phytocoenosis was examined based on biometric indicators of trees in central rows, trees in edge rows, and ground vegetation cover. The number of biogroups per hectare ranged from 210 to 240, with maximum stand density (up to 5,000 plants/ha) recorded in 13–15-year-old stands. In the central parts of the biogroups, 25-year-old trees had a mean stem diameter of 8.7 cm and a mean height of 7.9 m. Tree mortality was most intensive during the first decade of growth. Maximum standard deviation for diameter was recorded in 25-year-old stands (δ = 2.9 cm); minimum deviation was observed in 5-year-old biogroups (δ = 1.0 cm). Coefficients of variation for diameter (41–43%) exceeded those for height (30–33%), indicating greater variability in radial than in vertical growth. These findings confirm that intra-specific competition is most intense in younger biogroups and provide a scientific basis for optimising stand density in sustainable forest management of the Eastern Zangezur region.