Effect of the Local Heat Potential on the Distribution of Sessile Oak Forests

Abstract

ABSTRACTThe study was carried out in sessile oak forests—Quercuspetraea (Mat) Liebl. in the region east Serbia. The stands are classified as pure stands with individual percentage of other species, pure sessile oak stands with the percentage of other species up to 10% per tree number, and mixed forests of sessile oak with other species, whose percentage does not exceed 50%. Altogether 850 sessile oak stands were monitored.By the applied method of defining the local heat potential (18), modified by Krstić, (12), which represents potential possibility of soil heating without vegetation, the thermal co-ordinates of exposure (aspect) and slope (E=1–9), and the co-ordinates of altitude (V=1–18) were determined. In this way, a scale of 162 possible combinations of local heat potential was obtained, which explains more precisely the dependence of sessile oak stands on the topographical conditions.By applying the weighted mean values of the thermal co-ordinates of aspect and slope (E) for each altitudinal belt of 100 m, it was concluded that pure sessile oak stands have the widest ecological range. They occur at the sites with 24 combinations of thermal co-ordinates E.V = 6.12 to 9.16. Mixed stands of sessile oak and beech are located on the terrains with 21 combinations of thermal co-ordinates E.V= 3.16 to 9.16. Mixed forests of sessile oak and Turkey oak have the narrowest ecological range. They occur at the sites with 7 combinations of thermal co-ordinate E.V= 5.16 to 9.16.