Research on urban climates has been an important topic in recent years

Brief information about water balance of the Carpathian temperate forest ecosystem are presented in the paper. Experimental research was done in a mature mixed fir-spruce-beech stand in the research plot "Poľana-Hukavský grúň" (850 m a.s.l.) in the south-eastern part of Poľana Mts. in the Biosphere Reserve UNESCO in Central Slovakia. Individual parameters of water budget have been continuously monitored. The water consumption of the model beech trees, as well as approximate model beech stand transpiration was estimated on the basis of sap flow measurements and up-scaling through dendrometrical approach. Sap flow of model beech trees was estimated by direct, non-destructive and continuous measurements by tree-trunk heat balance method with internal heating and sensing of temperature. These values were compared with potential evapotranspiration according to Türc. Precipitation parameters (rain and snow precipitation, through-fall precipitation, stem-flow, fog/snow precipitation and infiltration) have been measured simultaneously. Results of mass water balance and the portion of the tree transpiration within the individual water flows are presented. Evapotranspiration of beech-fir forest ecosystem in the middle mountain region (850 m a.s.l.) includes: transpiration (35% of precipitation total), interception (21%), evaporation (8%). There are differences between tree species in mass of transpirated water. Transpiration of spruce and fir reaches two-thirds of beech transpiration. Fog precipitation contribution to the water balance of beech-fir stand is 5%. Concurrently fog precipitation lowers the interception losses of vertical precipitation.

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AbStRACt:The paper presents the results of a regional analysis of climate change impacts on Norway spruce growth in the north-western part of Slovakia (Orava region). Radial increment was determined from nine X-tree sample plots established in the forests of natural character in the region. The analysis of PTT radial increment was done on tree disks cut from a height of 1.3 m by measurements of four perpendicular directions corresponding to the cardinal points. It was derived from the tree-ring width measured at breast height (1.3 m) while all the basic principles of tree-ring analyses were observed (transport and borehole treatment, measurements with digital positiometer to the nearest 0.01 mm, synchronisation of the tree-ring diagrams). A dendroclimatic model belongs to the category of empirical models based on the statistical evaluation of empirically derived dependences between the time series of tree-ring parameters and the monthly climatic characteristics. This statistical evaluation is based on a multiple linear regression model. Climatic models were used as basic tools for climatic change prediction. There is a scenario coming from the GCM category, which is derived from the models of Canadian Centre for Climate Modelling and Analysis in Victoria (British Columbia, Canada), used for a solution of this task. It is the latest connected model from the second generation designated CCCM 2000. For the purpose of this study the area averages were modified for the meteorological station Oravská Polhora with the 1951-1980 reference period. The modification includes two climatic characteristics, total monthly precipitation and monthly temperature means. The frequency analysis indicates that 24.4% of trees would react to the assumed climatic change negatively, i.e. by decreasing the increment, and 75.6% of trees would react positively. Most of the reactions are moderately positive. It is to conclude that 14.6% of trees will react to a climatic change significantly in a negative way, the reactions of 34.1% trees are considered to be unchanged and 51.3% of trees should react to the assumed climatic change positively (P = 0.95). It results from the analysis of the climatic change impact that the highest effect on stands situated on the upper forest limit can be expected.

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