Acta Agrobotanica (Dec 2012)
Occurrence of disease symptoms and selected biotic factors connected with beech (Fagus sylvatica L.) dieback phenomenon in stands of The Magurski National Park
Abstract
The studies were carried out in 12 beech stands, growing on mountain fresh forest site in Magurski National Park. Stands differed in respect of exposition (northern and southern) and age - lower age classes (21-60 years old) and higher age classes (81-120 years old). This paper presents evaluation of frequency of disease symptoms occurrence in the crowns and on the trunks of beeches. The presence and the place of occurrence of fungus Ascodichaena rugosa and insects Cryptococcus fagisuga and Ectoedemia liebwerdella, which could be connected with beech bark necrosis on the trunks were noted down. In each stand 50 trees, growing side by side in center of the stand, were analyzed. Among 600 analyzed trees of Fagus sylvatica, 2.6% had a dead top. Crown thinning were present on 51.8% of trees. It appeared frequently in higher age class stands and didn't cover more than ¼ of the crown. Moreover, in crowns of 4.1% of trees the leaf chlorosis appeared. The most frequent symptom on trunks of beeches were local necroses (98% of trees), that were sometimes connected with slime fluxing (3.3%). Necroses were the most number in stands growing on the southern exposition and on south parts of the trunks. Cryptococcus fagisuga appeared mostly in high age class stands. Intensity of its appearance was similar on the trees growing on the southern and northern exposition (respectively, 48.3% and 53.3%). Particular parts of the trunks were colonized with similar frequency by C. fagisuga irrespective of cardinal points (N-29.3%; S-21.7%; W-22.7%; E-26.2%) and number of necroses on the trunks. Ascodichaena rugosa appeared on 8.6% of trees, more frequently on their north parts of the trunks (7.3%). In the places colonized by fungi A. rugosa, insect C. fagisuga was absent. Occurrence of larvae of Ectoedemia liebwerdella was mostly found on trunks of beeches growing on the southern exposition (43.0%), on 35.3% of trees they colonized south parts of trunks. There wasn't observed any connection between the occurrence of these larvae and symptoms of local necroses.
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