DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 7-8/2020 str. 45     <-- 45 -->        PDF

2 =1.361; p = 0.954). In 2018 the mean tree heights per treatment were 31.0, 31.6 and 30.9 m in control, moderate, and high thinning intensity, respectively and were not statistically significant (χ2 = 0.117; p = 0.943).
Average annual diameter increment was highest for predominant trees (n=391), 0.43 cm/year (Figure 7), slightly lower for dominant trees (n=555), 0.33 cm/year, and even lower for co-dominant trees (n=207), 0.24 cm/year and trees in the middle stratum (n=25), 0.11 cm/year (χ2 = 410.056; p < 0.001). The most vigorous trees (n=408) added 0.45 cm/year on average (Figure 7), moderately vigorous trees (n=463) 0.12 cm/year less than the most vigorous trees, and the least vigorous trees had diameter increment of only 0.21 cm/year (χ2 = 649.661; p < 0.001). Sociologically progressive trees (n=391) on average grew faster (0.43 cm/year) than sociologically stable trees (n=555), which averaged 0.33 cm/year (Figure 7) and sociologically regressive trees (n=232), which grew 0.22 cm/year (χ2 = 401,944; p < 0,001).
Crop trees (n=572) had higher average annual diameter increment than competitors (n=396) and indifferent trees (n=210), 0.42 cm/year (Figure 7). Competitors grew 0.12 cm/year slower and indifferent trees 0.19 cm/year slower than crop trees (χ2 = 448.172; p < 0.001). Trees with average crown length (n=669) grew on average 0.41 cm/year (Figure 7), while trees with short crowns (n=508) grew 0.25 cm/year (χ2 = 497.668; p < 0.001). The results are similar for quality (Figure 7): the highest quality (n=195) trees grew fastest, 0.45 cm/year, while those of slightly lower quality (n=539) grew 0.38 cm/year and trees of the lowest quality (n=444) 0.26 cm/year (χ2 = 405,379; p < 0,001).
Among the largest 100 crop trees/ha the differences in annual diameter increments varied little by thinning model as well (Figure 6). The largest crop trees in control fields grew slowest, 0.46 cm/year on average, followed by trees in moderately thinned fields, which averaged 0.48 cm/year. The largest crop trees in high intensity thinning fields grew fastest, 0.50 cm/year. We did not detect statistically significant differences in annual diameter increments among thinning intensities (χ2 = 4.720; p = 0.094). But there were statistically significant differences in annual diameter increment by vigour (χ2 = 33.586; p < 0.001), crown length (χ2 = 12.081; p < 0.01) and quality (χ2 =7.709; p < 0.05). We did not however detect statistically significant differences in annual diameter increment by stratum (χ2 = 3.360; p = 0.186) and evolutive trend - tendency (χ2 = 3.360; p = 0.186).
For the 100 largest-dbh crop trees it was determined that there are no statistically significant differences among thinning models in stratification (χ2 = 8.084; p = 0,089), vigour (χ2 = 3.354; p = 0.500), tendency (χ2 = 8.084; p = 0.089),