Confronto tra metodi di diradamento in un impianto puro d farnia (Quercus robur L.)

Comparison between different thinning systems in a pure common oak plantation.- First results of thinning trials, in a 19 years old pure common oak plantation, carried out during winter 2001/2 are reported. A previous thinning had been applied in 1993. Two different thinning methods were tested: systematic-selective method (50% tree felling) and selective thinning method (felling around 80 target tree per hectare). In spite of different thinning intensity (43% and 28% of basal area) in order to keep constant the diameter increments of target trees, the effects of both methods were similar. During the first five years after thinning, the target trees in both thinned plots showed constant diameter increments around 1,1 cm , while in the control plot the diameter increment decreased progressively to 0,7 cm. After thinning and pruning, epicormic branches developed on target trees. In the specific, about 68% of target trees in the thinned plots are characterized by epicormic branches, although only the 17% are vigorous. In the control plot, 62% of target trees developed epicormic branches, none of them vigorous