Thinning experiment in beech stands in the Mirna gora research site

V današnjem času nega mlajših gozdnih sestojev predstavlja glavni strošek lastnika pri gospodarjenju z gozdom. Da bi stroške zmanjšali, so bili ob klasičnem izbiralnem redčenju razviti alternativni načini redčenja gozdnih sestojev (t. i. situacijska redčenja). Z namenom preveriti učinke različnih tipov redčenj je bil v gozdnogospodarski enoti Mirna gora osnovan raziskovalni objekt za dolgoročno spremljavo učinkov redčenj v enomernih čistih bukovih sestojih. V objektu je bilo postavljenih osem raziskovalnih ploskev velikosti 4–9 arov. Tipi redčenj, ki so bili analizirani, so bili klasično izbiralno redčenje (obravnava A), situacijsko redčenje po Abetzu (obravnava B), situacijsko redčenje po Schützu (obravnava C) in kontrola (obravnava D). Tip redčenja je bil vsaki ploskvi določen naključno. Na ploskvah so bila izmerjena in ocenjena vsa drevesa nad merskim pragom 5 cm. Jakost redčenja glede na število dreves, temeljnico in lesno zalogo je bila višja pri obravnavi A kot pri obravnavah B in C. Jakost redčenja, izražena kot število konkurentov na izbranca, je bila pri obravnavi A nižja kot pri obravnavi B in višja kot pri obravnavi C. Delež javorja med izbranci je bil v primerjavi z njegovim deležem v skupnem številu dreves večji. Analize nakazujejo prednost situacijskih redčenj v primerjavi s klasičnim izbiralnim redčenjem, a zanesljive ugotovitve bodo podale analize ponovitvenih snemanj raziskovalnega objekta.Tending and thinning of younger forest stands is the main cost for the owner in managing the forest. In order to reduce costs, alternative methods of thinning (i.e. situational thinning) have been developed in addition to the classical selective thinning. In order to monitor long-term effects of different types of thinning, a research facility was established in the Forest management unit Mirna gora. In pure beech stands eight 4-9 are large research plots were established. The types of thinning analyzed were classical selective thinning (treatment A), situational thinning after Abetz (treatment B), situational thinning after Schütz (treatment C), and control (treatment D). The thinning types were randomly assigned to the plots. All trees above the threshold of 5 cm were registered on each plot. The thinning intensity with respect to the number of trees, the basal area, and the growing stock was higher at treatment A than in treatments B and C. The thinning intensity, expressed as the number of competitors per crop tree, was lower in treatment A than in treatment B and higher than in treatment C. The proportion of sycamore maple among the crop trees was higher than its share in the total number of trees. Our study suggested a preference for situational thinnings over conventional selective thinning, but more reliable findings will be provided after re-measurements and re-evaluation of gathered data