Geographic information system (GIS) application for windthrow mapping and management in Iezer Mountains, Southern Carpathians

Abstract

Windthrow problem is a difficult task for the forest managers in the Romanian Carpathians and especially in Iezer Mountains. The last windthrow, in July 2005, affected about 370 ha within the study area and left unprotected large slopes with important declivities (20–30°). In our study, we try to propose a tool for forest management, in order to control and minimize the negative effect of wind upon the mountain forest ecosystem. The digital data input derived from forestry data (forest stand typology, age, canopy coverage index, forest productivity class) and from the forest biotope features (soil and topography parameters). The main goal was to find a more objective way for digital layer reclassification in order to obtain the windthrow areas susceptibility map for the Iezer Mountains. Each digital layer has its own weight within the analysis and one of them was difficult to be modeled (the wind features). A statistical approach was developed on the basis of local phenomena and the windthrow features in the Romanian Carpathians. This allowed us to obtain the reclassification conditions for each digital layer. Forest canopy typology and soil features (mainly its volume) were considered as the key factors for the windthrow occurrence analysis. The final windthrow susceptibility map was validated with the help of the statistic occurrence of windthrow areas within each susceptibility class and after a field check of the sites. The result was encouraging, because 92.5% of the windthrow areas fall into the highest windthrow susceptibility class.