In our research, we examined the influence of tree crown size and social status on growth of the main tree species Norway spruce, silver fir and European beech in montane beech forests. Tree measurements were carried out in the Okroglina forest management unit on 55 permanent sample plots. In general, we found a predominance of the ellipsoidal crown form, while conifers were dominated by the conical crown form. Statistically significant differences in the crown width, length, area, and volume were found between tree species. Beech had the largest mean crown width (5.87 m) and fir the largest mean crown length (17.87 m). The largest mean crown surface was found for fir (219.3 m2) and the largest mean crown volume for beech (270.2 m3). We also found a significant effect of the tree social status on the shape and size of its crown. The analysed fir trees had the largest diameter and volume increments (0.35 cm/year and 0.034 m3/year, respectively), slightly lower increments were observed for spruce and the lowest for beech. Regression analysis revealed a significant effect of crown surface and volume on tree growth, with regression functions were often having parabolic shape, meaning that large crowns had a negative effect on tree growth. However, not all regression functions were parabolic some regression relationships were linear. We concluded that crown shape and size are species-specific and strongly influenced by the tree social status. Crown size has importantly effect on tree growth, but the effect species-specific and depends on the social status of the tree. We suggest further investigation of other potential influencing factors to improve the explanatory power of the models.
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