Effect of thinning on tree damage from the 2014 ice storm in the Idrija region

Februarski žledolom leta 2014 je na Idrijskem naredil ogromno škode. Da bi izvedeli še kaj več smo se podali na teren, kjer smo analizirali negovane in nenegovane sestoje in ugotavljali, ali redčenja v bukovih sestojih vplivajo na poškodbe dreves po žledu, ali pa je bila ujma tako neselektivna, da teh razlik ni bilo zaznati. Glede na negovanost smo v vsakem sestoju postavili 12 ploskev v velikosti 200 m2. Na terenu nas je najbolj zanimala stopnja poškodovanosti na izbranih ploskvah, ugotavljali pa smo tudi število mrtvih dreves in socialni položaj dreves ter še nekatere druge parametre. Ugotovili smo, da je v negovanih sestojih značilno manjše število dreves z močno poškodovanimi krošnjami. Razlike v pojavljanju drugih tipov poškodb v negovanih in nenegovanih sestojih niso bile značilne, kar kaže na to, da je bila ujma zelo močna in zato tudi delno neselektivna. Največ nepoškodovanih dreves je bilo med podstojnimi drevesi, največ močno poškodovanih pa med soraslimi drevesi. Nadrasla drevesa so imela najmanj močnih poškodb. Poškodovanost se je povečevala z večanjem naklona, vendar so bile razlike majhne in v našem primeru naklon ni bil najpomembnejši dejavnik, ki vpliva na poškodbe. Najbolj prizadeta drevesna vrsta je bila bukev, najmanj poškodb pa smo zabeležili za jelko.Ice storm in February 2014 in the Idrija region caused a lot of damage to the trees. We wanted to know a little bit more, so we went onto the field where we analyzed thinned stands and the ones that were not thinned to determine whether thinning affects the damage after ice storm in beech stands. We established 24 plots each with 200 m2 in the area in thinned and not-thinned stands. We wanted to know how damaged the trees were and find out the number of dead trees, their social status and some other parameters. All the data was analyzed using simple parametric and non-parametric statistics. We found out that in thinned stands, there is a smaller number of trees with severely damaged crowns. The occurrences of other types of injuries in thinned and non-thinned stands were not significantly different, indicating intensive disturbance and therefore partially non-selective damaging. The proportion of the undamaged trees was highest in the understory layer, while the number of the most severely damaged trees was highest in the canopy layer. We found only small proportion of emergent trees that were heavily damaged. The damage increased with increasing inclination, but the differences were small and in our case the slope was not the most important factor that affected the tree injuries. The most affected tree species was beech, and the least damage was recorded for the silver fir