Urban forests provide many benefits and ecosystem services respectively. Regulating the volume of water resources can be recognized as their hydrological function. In the area of City Municipality of Ljubljana, stand precipitation (the sum of throughfall and stemflow) in two selected peri-urban forests (near Gameljne) and one urban forest (Rožnik) with different tree species composition and stand structure were examined. Throughfall was monitored on the research plots in the lowland floodplain hardwood forest along the Sava river, in riparian Scots pine forest and in the mixed forest of sessile oak, sweet chestnut and Norway spruce. Gross precipitation were measured in nearby open areas % meadows. Stemflow was estimated by using relevant studies. The results show, that the average estimated proportion of stand precipitation (% of total rainfall), over the analyzed period from 2008 to 2013, was the largest in riparian Scots pine forest (96,1 %) and the lowest in mixed forest on Rožnik (82,0 %). In the floodplain deciduous forest, its average share was 92,9 %. The proportion of stand precipitation in riparian Scots pine forest and in floodplain deciduous forest in Gameljne was much higher during the dormant period, but in mixed forest on Rožnik, it was higher in growing season. In conclusion, stand precipitation is not affected only from the stand structure and its species composition, but precipitation intensity can also play an important role. These forests represent quality and quantitative filter for precipitation water. With the interception and retention of rainfall in treetops, they mitigate erosion processes and the effects of extreme weather phenomenons.
|
