Radial growth dynamics of Norway spruce in Kysucké Beskydy Mts.

The paper analyses basic features of radial increment dynamics of Norway spruce in region Kysuce. The study was conducted in a mature mixed beech-spruce forest stand that was managed by the clearcutting system. In the studied stand, 30 Norway spruce individuals from the overstory were selected and cored. The cores were subsequently analysed by the dendrochronological techniques. Standard descriptive statistics were calculated by COFECHA software and the mean ring-width chronology and standardized chronology was produced using the program ARSTAN. Besides the ring widths also the dynamics of basal area increment (BAI) was studied. The identification of past release events in the stand was made by the application of boundary-line method. The results confirmed an obvious decline of radial increment from early 1970's to early 1990's. A positive trend in increasing the radial growth was registered since approximately the mid-1990's. Analysis of disturbance history detected only an overall low percentage of trees showing a release, whereas most of them were of the moderate level. This fact suggests a relatively low intensity of thinnings during the rotation period and their weak impact on radial growth. The identification of a certain proportion of trees with a growth pulse in 1990's confirmed the ability of Norway spruce to response to the improved growth conditions even in a higher age.