Alien woody plants in Polva county: twenty-five years of changes
2000
Elliku, J. | Paivel, A. | Sander, H. (Tallinn Botanical Gardens, Tallinn (Estonia))
This article presents an analysis of the changes in the richness of foreign woody plants in the South-East Estonian county of Polvamaa that had occurred between two periods, 1958, 1960 and 1961 on the one hand and 1983 and 1985 on the other, as evidenced by the inventories made of the Polvamaa arboreta and parks in these years. Forty-two estate and parsonage parks were entered in the inventory in 1958, 1960 and 1961. A total of 211 taxa was registered in these parks. The inventories of 1983 and 1985, however, evidenced 251 taxa in 45 arboreta and parks, marking an increase by 40 taxa. The number of taxa registered during both periods of stocktaking was 158. Thus it appears that the specimens of 53 old taxa had disappeared from while those of 93 new taxa had emerged in the stock over the 25 years. In total, 268 taxa in 47 habitats were registered in these two periods. Of that number, 51 taxa were coniferous trees
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