Prilog fitocenološkim istraživanjima šuma crne johe (Alnus glutinosa Geartn) u Podravini

Zagreb

2006

S. 479-492

3 Abb., 23 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200136187

Forests of common alder in Croatia cover approximately 8000 ha (Prpić and Milković 2005). The most valuable stands are found in the management unit Đurđevačke nizinske šume in Podravina. In this area common alder forms pure or mixed stand extending over about 2000 ha. The stands manifest distinctly regular growth of good quality. From a phytocoenological aspect they are characterized by a natural, diverse and rich composition. The two associations dominated by common alder were studied and described in detail by M. Glavač in his dissertation of 1960. These associations include the phytocoenosis of common alder and elongated sedge (Carici elongatae-Alnetum glutinosae) growing in floodplain sites with stagnant water and micro-depressions, and a much drier community of common alder and narrow-leaved ash with birdcherry (Pruno-Fraxinetum) continuing onto the former community. There have been many changes in the past fifty years elapsing since the research by Glavač, including the construction of hydropower stations on the river Drava, drastic ecological transformations and regeneration of the majority of common alder forests. We have undertaken phytocoenological research in order to assess the consequences of the changes on the structure, dynamics and composition of these two associations. The planned field research was carried out in the vegetation period of 2006 using the standard method of the Braun-Blanquet school. In doing so, we were able to analyze and compare the findings, since former research was also conducted using the same method. Stands with a stable floral composition aged 50 and over were used for relevés. The relevés were sized 20 ̸20 m on average. A total of 28 relevés were made: 7 in the forest of common alder with elongated sedge and the rest in the association Pruno-Fraxinetum. Mosses were not considered. The forest of common alder with elongated sedge (Carici elongatae-Alnetum glutinosae W. Koch 1926) in Podravina grows on peat and base-rich, humus gleyic soils saturated with water, which separate this community from the adjacent ones.