Disastrous ice breaks in Eastern Serbia: GIS analysis of their relationship with orographic characteristics

Abstract

At the end of November/beginning of December 2014, an ice wave hit the whole of Eastern Serbia and caused extensive ice and snow breaks in the forest areas managed by SE `Srbijašume` - Forest Estates of Niš, Boljevac, Kruševac, Despotovac and Kučevo. The areas affected were determined by identifying all the affected units of forest division - with the lowest accuracy at the level of forest stands and, where possible by GPS recording in the field in order to ensure greater accuracy. The identified areas were presented in GIS mapping software. The total area affected by ice breaks amounted to 19,419.78 ha. It included 8,301.01 ha of high forests, 8,997.37 ha of coppice forests and 2,121.40 ha of artificially-established stands. Considering the size of the forest area affected by ice breaks on the one hand, and the huge environmental impact of forests on the other hand, this phenomenon may be considered a natural disaster. Having identified the affected forest areas, an analysis of the relationship between orographic characteristics and ice break occurrence was carried out with the use of GIS tools. The following orographic characteristics were studied: the elevation, the terrain aspect and the slope, all obtained from the digital elevation model (DEM) at a resolution of 1 arc-second. Elevation had the greatest influence on the occurrence of ice breaks. The largest area affected (ca.17,000 ha) was in the range from 600 to 900 m above sea level, i.e. in the belt of low-mountain relief. Regarding the aspect of the investigated terrain, the largest areas affected by ice breaks had northern (ca. 4,000 ha) and northeastern aspects (ca. 3,500 ha), while the remaining areas were equally distributed in all other aspects. The slope was not found to have any significant effects on the occurrence of ice breaks. This disaster brought about most severe and extensive consequences in broad-leaved and coniferous ecosystems and the environment in general, with long-term adverse effects such as changing soil water regimes, erosion, declining atmospheric oxygen levels and reduced carbon accumulated in biomass.