In this thesis, we compared data on the presence of tree species in publicly available databases of Slovenia Forest Service with actual situation in the Tivolski hrib forest area in Ljubljana. In the 40.5 ha study area, tree species were recorded during a field survey. For each tree, diameter at breast height was measured, quality and vitality were assessed, and its location was recorded. Spatial distribution was analysed using QGIS. A total of 193 trees belonging to 21 tree species with minor proportions in the growing stock were recorded, corresponding to 4.8 trees/ha. The Slovenia Forest Service databases listed 13 tree species, while the field survey identified a total of 31 tree species. This confirmed the hypothesis that actual tree species diversity is greater than shown in the inventory
data. The total volume of tree species with minor proportions was 123 m³ or 3.04 m³/ha, representing 0.9% of the total growing stock. The mean diameter at breast height was 21 cm, and 78.8% of the trees were in the 10–30 cm diameter class. The mean quality score was 3.3. The hypothesis that thin trees of poorer quality prevail was only partly confirmed. The mean vitality score was 2.5, indicating favourable vitality. Overall, 59% of the analysed trees were located within 20 m of roads and paths.
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