THE ROLE OF CLIMATIC FACTORS ON FOREST LANDSCAPE CHANGE IN THE GURGHIU BASIN

Wind is the main factor involved in changing the natural balance of forest ecosystems from Gurghiu hydrographic basin. Strong winds are responsible for windthrows, especially in spruce arboretums, the most representative of the wood species form the studied area. Trees can be partially (bending of trunks, branches and broken tops) or totally (pulling the roots) damaged. Windthrows occurrence is closely related to the climatic factors, physical-geographical conditions (slope, soil characteristics) and arboretum characteristics (structure, age, consistency) are also important. The imbalance induced by those phenomena is emphasized by pest invasions (especially Ips Typographus) which are quite frequent after windthrows.Our study represents a detailed analysis of the way in which the structure and the balance of the forest ecosystems of Gurghiu basin undergo major changes, because the climatic factors (wind, snow) action. Case study is the windthrow occurred on June 2010, when 200,000 m3 of wood was windthrowed, over a total area of 5,953 ha in P.U. II Isticeu (Fancel Forest Range) and partially in P.U. I Gl j rie (the same forest range). The methodology used includes the analysis of climatic data, statistical data processing, GIS techniques for mapping the areas vulnerable to windthrows, synthesis.