Abstract
Elevation above sea level is one of the key orographic factors determining the spatial distribution, structure, and productivity of Norway spruce stands in the Ukrainian Carpathians. This study aimed to identify patterns of altitudinal differentiation in their stands structure and productivity and to define analytical groups for further investigation of assortment structure. The study was based on the forest compartment database of the Ukrainian State Forest Management Planning Association “Ukrderzhlisproekt” as of 1 January 2022. A total of 96,876 first‑layer forest inventory compartments covering 320,679.9 ha were analysed; in each compartment, spruce accounted for at least three units of the stand composition and elevation above sea level had been recorded. Area-weighted mean values, quantile characteristics of growing-stock distributions, and the non-parametric Kruskal-Wallis test were used in the analysis. The largest area of spruce stands was concentrated within the elevation range of 1,000-1,149 m above sea level, amounting to 83,760.3 ha, or 26.1%. This elevation range also had the highest area-weighted mean growing stock for the entire set of stands, at 377 m³·ha⁻¹, and for mature stands, including overmature stands, at 479 m³·ha⁻¹. The total area of mature and overmature stands was 64,699.0 ha, with their highest proportion within an individual elevation range occurring at high elevations. Differences in the growing stock of mature and overmature stands among elevation ranges were statistically significant, while the highest median and quartile values were likewise recorded at 1,000-1,149 m. Records for which elevation had not been established accounted for 7.6% of the area in the initial dataset and were excluded from the analysis of altitudinal differentiation. Changes in growing stock along the altitudinal gradient were also associated with the trophic status of forest-site conditions, age structure, relative stocking, and the proportion of spruce in the stand. The highest area-weighted mean growing stocks of mature and overmature spruce stands were recorded under fairly fertile and fertile site types, whereas values were substantially lower under infertile pine and fairly infertile pine site types. The practical significance of the findings lies in substantiating an elevation-, age-, and site‑type-based approach to selecting stands and model trees for assessing the assortment potential of Norway spruce