DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 13/2005 str. 250 <-- 250 --> PDF |
1. Tikvić, Z. Sclctkovic, N. Magdić. V. Sojal: THE CONDITION AND RELATIONSHIP OF PRECIPITATION ... Šumarski list SUPLEMENT (2005), 247-24X THE CONDITION AND RELATIONSHIP OF PRECIPITATION WATERS IN THE FOREST ECOSYSTEMS OF PLITVICE LAKES NATIONAL PARK Ivan TIKVIĆ, Zvonko SELETKOVIĆ, Nikola MAGDIĆ, Višnja ŠOJAT SUMM AR Y: Plitvice Lakes National Park is characterised by natural lakes with clean and clear water and a variety of waterfalls splashing over travertine barriers. Forest ecosystems, which take up about 76 % of the area, are one of the basic prerequisites for a balanced runoff of precipitation water, the provision of clean and clear water, the control of erosion and the formation and maintenance of the lakes. Since beech is the principal tree species in these ecosystems accompanied by substantial amounts of silver fir and spruce, research was conducted in these three main forest ecosystems. Research was aimed at establishing the impact of forest ecosystems on the dynamics and quality of precipitation water, or their direct influence on the condition of sur face waters and eutrophication of the lakes, which has become an increasingly important issue. The condition of precipitation water was determined on the basis of weekly and bi-monthly precipitation samples and their physical-chemical composition outside the forest (check samples) in nine different sites in the forest. Research included depositions of pollutants (sulphates, nitrates) or dry gravitational depositions of floating particles and wet depositions. In the forest ecosystem of common beech the precipitation quantities (maximal, medium and minimal values) were lower than those measured outside the forest. In the forest ecosystem of silver fir and common spruce, maximal values of precipitation quantities exceeded the values outside the forest only in cases of heavy rains, while the average values were lower than those outside the forest. Similar results were found in the forest ecosystem of silver fir and common beech. The results point to different impacts of forest tree crowns on runoff, discharge and percolation of precipitation water and to variable impacts of forest ecosystems on the condition of precipitation waters with regard to different precipitation intensities. The average interception for all three ecosystems during heavy rains ranged from 25-30 %. Significant precipitation with pH values below 5.6 was found both outside and in the forest. These values were less represented in the forest ecosystem of common beech. In several cases pH values in the forest ecosystem were higher and more favourable in relation to the values outside the forest, which indicates a positive impact of the forest ecosystem on precipitation chemistry and pollutant depositions. This refers to other substances as well (CI, S04-S, N03-N and others) which were analysed in the paper. |