DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 13/2005 str. 216 <-- 216 --> PDF |
I. Tikvič. D. Puntarić. Ž. Zečić. D. Ugarković. Z. Seletković: TUF. IMPACT OF MONTANIi FOREST ... Šumarski list SUPLEMENT (2005). 202-218 ecosystems are considered the most stable hydro-geological ecosystems on Earth, which is corroborated by preserved soils in hilly and mountainous areas that sustain natural forests, and by clear and clean waters despite considerable aerial pollution and other adverse factors. Precipitation passing through the forest canopy (throughfall), leaf litter and forest soil is naturally purified and reaches underground layers in the form of drinking water. Trees and shrubs intercept precipitation and influence seepage, runoff and percolation (surface and ground runoff), soil erosion, filtering and purification (Tikvić and Seletković, 2003). This influence depends on the existing ecological and biological factors. The most important ecological factors are relief, parent substrate, soil and climate whereas biological factors include tree species, forest ecosystem structure and anthropogenic impacts. Springs, streams, underground and surface waters largely depend on the condition of the surrounding forest ecosystems. Natural or artificial changes in the condition of a forest ecosystem may cause changes in hydrological processes and chemism of watercourses (Bau ml er and Zech, 1999). According to Gallcr (1975; Starče vi ć, 2000), a forest may intercept and purify about 2,000 mJ of water per ha annually. Bearing in view the size of the forested area in Croatia, very large quantities of water are filtered by forest ecosystems annually. However, all ecosystems suffer from continuous and increasing pollution, which is reflected on water quality in forest ecosystems. Harmful effects of polluted air and rain on forest trees, soil, water and the human health have been confirmed by a number of researchers RESEARCH AREA The paper explores water quality of watercourses in the area of Papuk, the Plitvice Lakes National Park and Velebit. Samples in the area of Papuk were taken from the streams Brzaja and Dubočanka, and from the river Orljava. In the Plitvice Lakes National Park samples were provided by the streams Sušanj and Rječica, and in the area of Velebit from three springs and from the stream Tisovac. Table 1 gives the basic characteristics of the study area. Indicators of the general ecological water condition (physical-chemical indicators, oxygen regime, nutrients, microbiological and biological indicators), as well as the use of water (metals, organic compounds and radioactivity) were sampled and analyzed using the Croatian norms in the Institute of Public Health of the City of Zagreb. Physical-chemical indicators (pH and electrical (Fi lip an et al, 1996). Prpić et al. (1994) reported contamination of forests and agricultural areas with lead. According to these authors, forest soils are several times more polluted with lead than agricultural soils, which may be attributed to the structure of a forest and its role in water purification. However, B i n k e y et al. (1999) detected nitrate and phosphate concentrations in the watercourses of agricultural areas in the USA that exceeded those in forest watercourses by nine times. Despite increasing pollution in forests, waters in hilly and mountainous watercourses in Croatia have retained their purity and clarity, owing primarily to the positive effect of forest ecosystems. Hydrological processes in forests are also affected by forest management practices. Proper management with forests sustains the optimal condition of a forest ecosystem and ensures commercial and other forest functions. Management treatments have short-term negative effects on hydrological forest function, but this function is restored several years after thinning and selection cutting (Rosen et al., 1996, Bau ml er and Zech, 1999). According to Anders son et al. (2000), the problem of forest water quality is one of the vital priorities in forest ecosystem research. Yet, impacts of a particular tree species, soil type, different parent substrates and man on water quality in forest ecosystem watercourses still remain to be investigated. This paper analyzes waters in montane Croatia and assesses the impact of different forest ecosystems on the quality of water in watercourses. AND METHODS conductivity) and dissolved oxygen were determined with electrometric analysis, while chemical oxygen demand (COD) was determined with potassium permanganate titration. Nutrients (nitrates and nitrites) were determined spectrophotometrically, and metals were determined with the electrochemical method. Of organic compounds, mineral oils were determined with infrared spectroscopy, while phenols, lindane, polychlorinated byphenils (PCB) and DDT were determined with spectroscopy and gas chromatography. Microbiological indicators, or aerobic bacteria count, were determined by counting bacterial colonies growing on a nutritive medium at 22 °C and 37 °C. According to Water Classification Regulations (NN 77/98) and based on the allowed border values of individual indicators, waters were classified in different categories (I - V). RESEARCH GOAL The goal of research was to assess water quality of Another goal was to analyze differences in water qualiwatercourses in different forest ecosystems and exploty with regard to site and stand conditions and establish re the effects of forest ecosystems on water quality. differences in water quality of watercourses in and out |