DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 7-8/2001 str. 28 <-- 28 --> PDF |
B. Prpić: UTJECAJ V0D0TEHMČK1H ZAHVATA NA STABILNOST SASTOJINA HRASTA LUŽNJAKA ... Šumarski list br. 7-8, CXXV (2001), 379-390 and others). Roughly, these come to at least 40 million DM using a method from a by-law in the Forest Act - The Forest Management Regulation NN 121/97. According to the available data, the monetary value of electricity provided by the hydropower station Novo Virje would be below that obtained from the annual increment of the forests it jeopardises. 3. The lowland area of Podravina around Koprivnica and Đurđevac constitutes outstanding natural wealth consisting of well-preserved lowland forests, the flow of the river Drava with its river islands, pebbly sandbanks and riparian forests, pastures and wet meadows, old Drava backwaters, as well as traditional agriculture, hedges and woodlands. The entire area is characterised with high biological diversity, while the ecotones, the bordering zones between different ecological systems, represent a particular rich plant and animal world. The natural lowland forests, with a renowned forest of Repas on the left bank of the Drava, are highly valuable. There is a proposal to place this forest into the category of protected landscapes, but this proposal has not been processes yet due to a forced spatial plan with the Novo Virje hydropower station. We maintain that in the proposed Dunav, Drava, Mura Bioshpere Reserve, the lowland forests, including the forest of Repaš, would have a variety of very positive functions. These include natural- protective, tourist (ecological, hunting, peasant tourism), water-protective, hydrological, climatic, anti-emission and genetic, as well as raw materials functions for the development of clean and ecologically acceptable timber processing industry. 4. The final study on the environmental impacts entitled: HE NOVO VIRJE: ACCEPTABLE GROUNDWATER REGIME FROM THE STANDPOINT OF PRESERVING FOREST ECOSYSTEMS is inadmissible because one basic factor was not respected. Namely, experience of a hundred years shows that the existing water regime, influencing the development of middle- aged and older natural stands with pedunculate oak, is optimal for their growth. Furthermore, the calculation on the acceptable regime of groundwater is highly questionable, because the capillary movement of groundwater as an element of the mentioned calculation was obtained on the basis of estimated values, but without laboratory measurements. Also, the study encompassed only the forest of Repaš, which represents about 25 % of the forests to be affected by the erection of HE N. Virje. This forest differs from other forests by its vegetational composition and habitats, and therefore the results from RepaÜcannot be applied to all the forests in the area. 5. Dieback of pedunculate oaks in the forest of Repaš occurring during the past decade is the consequence of synergistic effects of a gradual drop in groundwater levels caused by the erosion of the Drava riverbed. The erosion was brought about by the action of the upriver hydropower stations (Čakovec, Varaždin, Dubrava), but also of the simultaneous drought to which lowland forest ecosystems have adapted through their long history. Had the groundwater not dropped due to the erosion of the Drava riverbed, the pedunculate oak would have survived the drought with negligible consequences. Water management authorities should find a way of halting the erosion of riverbeds and thus create more natural conditions for the lowland forests downstream of the HE Dubrava. Key words: lowland forests of pedunculate oak, climatic excesses, hydro-technical interventions, changes in water relations, dieback of pedunculate oak |