The effects of climatic factors on radial growth of Norway spruce Picea abies in the Silesian Beskids

Monitoring of Picea abies according to a standard tree-ring and correlation analysis was carried out on 9 plots in three forest districts of Jablunkov Forest Administration (Nydek, Písek, Horní Lomná) in the course of 2008. At each of the plots, 30 samples were always taken by means of a Pressler increment borer. Based on the regional standard annual-ring chronology particularly the increase is evident of radial increments in the second half of the 1990’s, which was interrupted in 2000. A two-year period with increased radial increments followed, which was interrupted again in 2003 and then in 2006. The diameter increment signifi - cantly correlates with precipitation in September of the previous year (Nydek, Písek,the group of all three districts) and precipitation in June of the current year (Nydek, Písek, the group). The growth of spruce also signifi cantly correlates with temperatures in October of the previous year (Písek, Horní Lomná), in March of the current year (Nydek, Písek, Horní Lomná, the group) and in April of the current year (Horní Lomná). The negative statistically signifi cant correlation of the increment was found for temperatures in September of the previous year (Písek). Further, negative pointer years were identifi ed. On the basis of results obtained it is possible to conclude that climatic factors of last circa 20 years markedly affected the vitality of stands. In the 1990’s, their eff ects can be particularly evaluated as predisposition. However, dry and warm weather in 2003 can be considered to be an initiation stressor showing a substantial or even key role in the present health condition of stands.