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Overstory-understory neighborhood effect in mountain mixed forest
Matouš, Marek ; Bače, Radek (advisor) ; Ulbrichová, Iva (referee)
The object of this study is to describe overstory-understory neighbourhood effects in natural mountain mixed forests in environmental conditions of central Europe. Namely, the neighbourhood effect of European beech (Fagus sylvatica L.), silver fir (Abies alba Mill.) and Norway spruce (Picea abies [L.] Karst. ).
The sample plots are situated in central Slovakia. On 60 plots, counts of individuals of these species were recorded and divided by social status (from 6 cm of DBH). Regeneration of these species, was divided into 4 high categories. For 30 trees of each species, regeneration was also counted under specific crown in the area of 4 m2. The data was evaluated mainly by the generalized linear model in R statistical program. Here was evaluated the relationship between individuals of different categories of understory and overstory and the dependence between counts of regeneration of each species under specific crown.
The strongest positive overstory-understory neighbourhood effect, was observed for the silver fir in all categories of regeneration (p<0.001). It also weakly negatively affected the regeneration of beech. For spruce, the positive neighbourhood effect was demonstrated only among the trees of upper level and saplings from 0.5 to 1.3 meters. Other categories of spruce saplings, were in too small quantities for demonstrating these relationships. Positive overstory-understory neighbourhood effect of beech was weak, or neutral for advanced regeneration. But seedlings to 0,5 m height, were in minimum quantity under spruce and fir crown. Beech also significantly negatively influenced all regeneration categories of silver fir (p<0.001). So, for each species, the overstory-understory neighbourhood effect is more or less positive, at least for lower height regeneration categories. This effect suggest also to small scale species stability of these forests.
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