Nikola Pernar

Spatial distribution of main forest soil groups in Croatia as a function of basic pedogenetic factors

The model of spatial distribution of main forest soil groups in Croatia was developed as a function of basic pedogenetic factors: lithological substratum, macroclimate and relief. Used data about soil group, lithological substratum, terrain slope and aspect were collected on 1881 soil profiles. Macroclimatic data were estimated for each soil profile by spatial interpolation between meteorological stations. Feedforward neural networks were used as modelling tool. The final model has total classification correctness of 63.5% for training data set and 62.3% for independent test data set. The best result (86.4%) was achieved for fluvisols which are strongly spatially correlated with alluvial sediment in a flood plains. The worst result was achieved for luvisol (14.2%) which mainly comprised very old soils, probably developed under pedogenetic factors different from actual. The model was applied on entire Croatian territory aiming at construction of potential spatial distribution of main forest soils (without human impact), which was compared by the potential spatial distribution of major forest types modelled independently.

Observed Climate Change in Croatia and Its Impact on the Hydrology of Lowlands

The lowland forests of South-eastern Europe present the remains of large forest areas, strongly influenced by periodic flooding and shallow groundwater tables. Their natural hydrologic regime was throughout history continuously exposed to various negative influences such as intensive forest exploitation and hydro-technical activities Nowadays there are more indices of regional runaway of climate change, which have caused a lowering trend in the groundwater tables and more intense droughts. To attenuate past, present and future negative impacts on the hydrology of lowlands, the possibilities of water table management were assessed. In this study, the procedure of estimation of the historic state of waterlogging based on a comparison of relict morphological indicators of hydromorphic soils and the present state of groundwater tables were developed. According to this, major influences on groundwater tables such as hydro-technical objects and disturbances of forest stand structure were assessed.