Štete od jelena običnog (Cervus elaphus L.) u sastojinama poljskog jasena (Fraxinus angustifolia Vahl) Srednje Posavine

Šumski ekosustavi složeni su sustavi u kojima je ponekad teško predvidjeti i objasniti procese međusobnog djelovanja i interakcije pojedinih čimbenika. Neodvojivi dio šumskih ekosustava su različite vrste krupne divljači. Divljač, a posebice krupni preživači i divlja svinja, u stalnoj su interakciji sa florom područja koje naseljavaju. Njihovi pozitivno/negativni utjecaji mijenjaju se tijekom različitih fenofaza i starosti sastojine te ovise o prisutnosti i brojnosti divljači, dostupnosti hranjiva i sl. Negativni utjecaji krupnih vrsta divljači predmet su brojnih istraživanja u svijetu i kod nas. U ovome istraživanju obrađene su štete koje uzrokuje jelen obični (Cervus elaphus L.) na kori mladih stabala poljskog jasena (Fraxinus angustifolia Vahl). Na dvije lokacije unutar poplavnog područja rijeke Save, u staništima gdje se preklapaju zajednice poljskog jasena i areal jelena običnog, izvršeno je istraživanje oštećenja na kori poljskog jasena. Rezultati pokazuju da guljenje kore mladih stabala jasena započinje odmah po uklanjanju zaštitne ograde kojim se sastojine štite u fazi oplodnih sječa. Oštećivana stabla jasena kreću se u rasponu prsnog promjera od 2 do 18 cm. Na stablima promjera 18 cm i više, zbog formiranja debljeg sloja mrtve kore, jeleni prestaju s guljenjem, a štete iz prethodnih godina postaju teže uočljive. Oštećivanja kore kreću od pridanka debla (vrata korijena) pa sve do 190 cm visine. Porastom promjera unutar raspona 2 – 18 cm, raste i stupanj prstenovanja odnosno kumulativna višegodišnja oštećenja. Na nekim lokacijama šteta je zabilježena na svim stablima poljskog jasena. Oštećenja nisu pronađena na hrastu lužnjaku (Quercus robur L.) i amorfi (Amorpha fruticosa L.) kao dvjema najzastupljenijim drvenastim vrstama pored jasena. Provedene analize kore ne upućuju da je nedostatak hranjiva, šećera ili minerala razlog zašto jeleni gule koru mladih jasenovih stabala.
Forest ecosystems are complex systems where it is often hard to predict and explain mutual activities and interactions of individual factors. Different species of big game make an inseparable part of these ecosystems. Game, particularly big ruminants and wild boar are in a constant interaction with the flora of the area they inhabit. Their positive and negative effects vary during different forest stand phenophases and depend on the forest stand age, presence and number of different game species, availability of food, etc. The negative effects of big game on forest stands have been studied worldwide and in Croatia as well. The focus of this research was to analyse the bark damage induced by red deer on young trees of narrow-leaved ash. The research was conducted in two narrow-leaved ash forest stands situated in the Sava river basin in Croatia, where red deer is known to be present. The obtained results indicate that debarking (bark peeling) of young trees starts immediately upon the removal of the protective fence which is usually put up around forest stands during the regeneration period. Diameter at the breast height (DBH) of damaged narrow-leaved ash trees varied from 2 to 18 cm. In trees of greater diameter, new bark peeling didn’t occur, and damage induced in previous years became less conspicuous due to the formation of thicker bark layer. Bark damage was visible from the root collar (ground level) up to 190 cm of the stem height. With the increase of DBH (in the range from 2 to 18 cm), the girdling intensity, i.e., the cumulative damage from previous years increased as well. In some research plots the damage was visible on all narrow-leaved ash trees. Bark damage induced by red deer was not observed on the pedunculate oak and indigo bush, which were the two most common woody species in the researched area just after narrow-leaved ash. Conducted bark analysis didn’t indicate that the lack of nutrients, soluble sugar or minerals is the reason for the extensive bark peeling of the narrow-leaved ash bark.