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ŠUMARSKI LIST 5-6/2019 str. 29     <-- 29 -->        PDF

Statistical analysis – Statistička analiza
Based on the number of growth flushes, all the plants were differentiated into one-flush growth (single flushing – with only the primary axis formed), two-flush growth and three-flush growth seedlings (with the season shoot growth formed in a multi-flush manner), i.e. the height growth types were determined (Bobinac 1997). The descriptive statistics parameters were determined for the analyzed elements of one-year-old Hungarian oak seedlings (total height, multi-flush growth, root collar diameter, number of leaves, total leaf area) for all the seedlings and growth types: arithmetic mean (x̄ ), standard deviation (sd), median (med), coefficient of variation (cv), minimum (min), maximum (max), skewness (skew) and kurtosis (kurt). Before the testing of arithmetic means, the testing of sample variances was conducted for one-flush growth and multi-flush growth seedlings using the F test. The testing of arithmetic means was conducted using the t-test assuming unequal variances and the distribution comparison was done using the Kolmogorov-Smirnov test. The testing was done using the programme package stats in R environment (R Core Team, 2018). The distributions of growth elements were modelled with Weibull’s probability density function using the Harter and Moore method (1965), in R environment.
When all 400 seedlings are observed (Table 1), the root collar diameter (Drc) is the least variable growth element with the coefficient of variation of 20.0%, while the total leaf area (TLA) is the most variable growth element (cv = 53.3%). All analyzed growth elements are characterized with distributions that have a right symmetry that is less expressed in the number of leaves (LN) and the root collar diameter compared to the total height (Ht) and the total leaf area. All growth elements have a leptokurtic distribution except the LN growth element that is platykurtic.
During the growing season, the height growth of Hungarian oak seedlings was developed through up to three phases (shoots) of growth. Therefore, three seedling growth types were defined: one-flush growth, two-flush growth and three-flush growth type.
In the analyzed sample, 39.8% of the seedlings belonged to the one-flush growth, 58.2% to the two-flush growth and only 2.0 % to the three-flush growth type (Figure 2).
Since only a small number of seedlings with three flushes was recorded, they were observed together with two-flush