Comparative studies of the spruce tree stand in the Tatrzański National Park

The paper presents the results of an investigation carried out at a permanent plot in spruce stand of the Tatrzański National Park in the years 1998--2006. Concentrations of phytotoxic gases in the air together with the load of acidifying compounds reaching the forest soil were characterized. The forest ecosystem response was evaluated by analysing the chemistry of the needles, changes in health status of trees and floral composition. Neither exceedances of the critical SO2 and NO2 concentration levels in the air nor the critical load of acidity were found. Only ozone concentration level was recognised as a potential threat to the trees. Heavy metal concentrations in spruce needles represented levels concerned as non-hazardous for the health status of the tree stand. The use of the spruce needles as a cumulative bioindicator showed the presence of PAHs with carcinogenic properties in the air. The investigated spruce stand belongs to the slightly damaged class, however in the period of 1998--2004 a deterioration of the spruce trees condition was observed expressed by a diminishing number of health trees. A comparative investigation carried out in the years 2001 and 2006 proved stability of the floral composition at the permanent plot.