engleski

The role of fungi in holm oak (Quercus ilex L.) crown dieback in Croatia

Holm oak is one of the most important tree species in the Mediterranean forest vegetation in Croatia. Occurring practically on the whole coastline area its ecological, social and economic importance is unquestionable. In the period 2007 - 2012 research has been carried out in several sites throughout the Croatian coast and symptoms of twigs and branches dieback were obtained in various parts of oak crowns. Laboratory analyses revealed several fungal species occurring bark of collected samples, although two of them turned out to be the most frequent: Dothiorella iberica A.J.L. Phillips, J. Luque & A. Alvesand, and Coryneum depressum Schmidt. Presence of these fungi on the young and healthy shoots and branches revealed their significance in observed holm oak dieback. One of the leading problems in tree dieback, that is considered to be crucial to the predisposal of trees to pathogens, are also the climatic changes. They are manifested as an increase of dry periods, an accumulated deficit of precipitation, and furthermore the precipitation regime throughout the year is highly unevenly distributed. Under the stress conditions caused by these changes, namely drought, trees were often predisposed to various damaging biotic factors.

Holm oak; Crown dieback; Dothiorella iberica; Coryneum depressum; Climatic changes; Stress conditions; Drought

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