The Problem of Determining Growth Losses in Norway Spruce Stands Caused by Environmental Factors

Abstract

Several reasons make it difficult to carry out accurate measurements to define the amount of reduction of increment in Norway spruce stands which is originated by air pollution. The main problems are described

• as difficulties to find undamaged stands for comparison purposes

• as possible mistakes resulting from high variability of results from yearring-analyses of single trees;

• climatic and soil parameter beside air pollution may influence yearrings

• as necessity to synchronize each yearring to be measured in order to avoid mistakes caused by missing yearrings; up to 24 missing yearrings were found in disks at breast hight.

Part of the difficulties could be overcome by analyzing disks both in breast hight and in higher parts of the trunk. Comparison of yearring diagrams resulting from analyses of limed and unlimed tree groups in an area which is characterized by acidified soils, justified losses of increment in the unlimed stand.