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Structure and dynamics of the black alder (Alnus glutinosa (L.) Gaerth.) population along Glogozka river in Osogovo mountain.

2007; Pensoft Publishers; Volume: 8; Issue: 1 Linguagem: Inglês

2815-2549

Tzvetan Zlatanov, Georgi Hinkov, Tatiana Stankova,

Peatlands and Wetlands Ecology

The main objectives of the present investigation were to examine the spatial structure, growth and regeneration potential of the black alder population (Alnus glutinosa (L.) Gaerth.) along Glogozka river in Osogovo mountain and to discuss the changes observed with the human invasion. Four sample plots were established along the river course. Diameter (DBH) distribution was analysed and age-height relationship was estimated based on the height growth of dominant trees. The natural regeneration was evaluated by the number of seedlings and saplings in 38 rectangular measurement plots (sized 2×4 m,) along 10 transects in the sample plots. The age structure of studied black alder population suggested that it was almost entirely cut during the period of intensive timber harvesting which started in the river valley at the beginning of the 60s of the last century. At the time of present study the species had recovered and took its niche along the river bed. This process was almost completed in the lower part of the studied area (sample plots 1 and 2), where normal pattern of DBH distribution was distinguished, but the lack of alluvial terraces and canopy openings coincided with the very low regeneration rate. In uppermost area of black alder distribution along the river course (sample plots 3 and 4) the species was still invading the adjacent open territories, the natural regeneration was abundant, though irregular, and deviation from the normal type of diameter distribution was found. The studied black alder population showed relatively good productivity and height growth potential and the species proved to be a pioneer capable of invading both eroded and alluvial soils. The population along the upper current of Glogozka river is in stable state and its conservation value will steadily increase, provided the current management and ecological conditions persist. k ey words: Alnus glutinosa, black alder, riverside plant community, population structure and growth, natural regeneration