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ŠUMARSKI LIST 5-6/2020 str. 52     <-- 52 -->        PDF

Tree shape – Oblik stabla
The H/D ratios were not statistically different at the initial planting densities of 1111 and 1667 stem ha–1, and lower than the other initial seedling densities (Table 4). The H/D ratios at initial planting densities of 3333 and 2500 stem ha-1 were 1.32 m cm–1, 21% higher than at other initial planting densities.
Although the live crown ratio decreased with an increase in initial planting densities from 1111 to 3333 stem ha-1, the difference between the spacing of 1111 and 1667 stem ha-1 was not significant (Table 3).
There weren’t significant differences among the q3.30 of trees at initial planting densities of 1111, 1667 and 2500 stem ha-1, and they were lower than that at the planting density of 3333 stem ha-1. The q5.50 and the d5.5/d3.30 ratios of trees at all initial planting densities were not statistically different (Table 3).
Branch characteristics – Karakteristike grana
Since self-pruning had not yet begun in the initial planting density of 1111 stem ha-1, there were no dead branches on the stems. The heights of the lowest dead branch of trees in the 2500 and 3333 stem ha-1 planting densities weren’t statistically different, and approximately 80% higher than that of the 1667 stem ha-1. There was no difference between the mean maximum diameter of dead branches in any of the initial planting densities except for the 1111 stem ha-1 density (P >0.05, Table 4).
Height to the lowest live branch increased with increasing initial planting density, but wasn’t different for the 1111 and 1667 stem ha-1 planting densities (P >0.05). The height to the lowest live branch in the highest initial planting density was approximately 2.1 m greater compared to the planting densities of 1111 and 1667 stem ha-1. Mean maximum diameters of the live branches in the initial planting densities of 3333 and 1667 stem ha-1 were not different statistically, and 27% higher than in the other densities (P <0.05)
Mortality – Mortalitet
No mortality was observed in any of the initial planting density plots, especially despite intraspecific competition in the higher initial planting densities. Although the light demand of narrow-leaved ash is high (Boshier et al. 2005), it can be noted that its tolerance to intraspecific competition is also high. In other studies, it has been reported that common ash (Fraxinus excelsior)  can survive under low light conditions for a long time compared to intolerant trees such as oak (Kerr 1995; Kerr and Cahalan 2004; Kuehne et al. 2013).
Tree growth – Rast stabla
In plantation forestry, the planting density significantly affects the growth and quality of trees (Smith et al. 1997) as competition for light, nutrients and water is intensified among the trees due to their increasing number (Savill et al. 1997). Accordingly, a tendency toward decreased tree diameter is expected as the planting density increases (Huang et al. 1999; Neilsen and Gerrand 1999; Kerr 2003; Mehari and Habte 2006; Alcorn et al. 2007; Benomar et al. 2012; Kuehne et al. 2013; Andrzejczyk et al. 2015). However, in this study, the initial spacing did not affect the mean diameter reached at the end of ten years. According to the results of the first three years of this study, there was no statistical difference between the spacing treatments in terms of mean diameter, but the mean diameter in the weed controlled plots was higher than that in the control plot (Çicek et al. 2010). Kerr (2003) stated that the mean tree diameter decreased as the initial spacing increased in a five-year-old common ash plantation which was not under weed control.
Height growth in plantations may vary depending on the tree species and the size of the growing space tested (Benomar et al. 2012). In broadleaved trees, with increased