Aim of the study:
The purpose of this study was to identify the changes in the share of ions in the chemical composition of waters, along longitudinal hydrochemical profiles with the increase in catchment area, in the area affected by the ecological disaster - dieback of spruces.

Material and methods:
The study was conducted in the Malinowski stream catchment that drains the Skrzyczne massif of the Beskid Śląski Mountains in 2013-2014. The Malinowski stream catchment was divided into smaller sub-catchments: dependent and independent and 6 longitudinal profiles along the catchment with the increase in catchment area. During field studies, water samples were collected monthly in catchments with various degrees of deforestation and the physicochemical characteristics of water were measured (pH, EC25°C, Tw). In the laboratory, the chemical composition of waters in the 14 ions range (Ca2+, Mg2+, Na+, K+, NH4+, Li+, HCO3-, SO42-, Cl-, NO2-, NO3-, PO43-, Br-, F-) was determined by ion chromatography (DIONEX 2000).

Results and conclusions:
The conducted research has shown the impact of deforestation on the share of ions in the chemical composition of waters. The share of SO42- in waters draining deforested catchments was so large that it appeared in the first place in the hydrochemical type of waters. Analyzing changes in hydrochemical types of water along longitudinal profiles it is necessary to pay attention to the different chemical composition of waters draining the upper zone compared to the lower zone.Analysis of the chemical composition of waters carried out in longitudinal hydrochemical profiles allows to identify the hydrochemical effects of deforestation.