Beskydy 2013, 6, 75-86
Change of stand structure in upper tree line caused by disturbances
In 2002, the series of 4 permanent research plots of different altitudes (difference 100 m) was established in forest stand that is the part of upper tree line. In the plots we registered the quantitative and qualitative biometric characteristics of individual trees. The results showed that the stand is relatively statically stable (sufficient parameters of crown ratio and slenderness). The studied stand had adequate density and the number of stems was increasing with the decreasing altitude (from 1,460 to 1,260 m a.s.l.). The stand was comparable with the model one (yield tables) regarding the quantitative as well as qualitative parameters.
After the wind disturbance in 2004, two studied plots in higher altitudes were totally destroyed. In the time of repeated measurements (in 2010) the negative impact of the bark-beetle outbreak began to be visible. It was reflected in increased mortality of spruce also in the research plots situated in lower altitudes of studied stand. We confirmed that the neglect of forest hygiene and adequate silvicultural treatment leads to decline of stand condition and functionality in the upper tree line forests.
