Radial growth trends of fir (Abies alba Mill.), beech (Fagus sylvatica L.) and pine (Pinus sylvestris L.) in the Świętokrzyski National Park (Poland)

The objectives of this study are to determine a trend of the radial growth at breast height (b.h.) and to compare the radial growth of trees of younger and older generations in the XX century for fir (Abies alba Mill.), beech (Fagus sylvatica L.) and pine (Pinus sylvestris L.) in the Świętokrzyski National Park. In the investigated area fir, 41 to 200-300 years of age at breast height, gradually regenerated its radial growth after a very strong decline during 1971-1990, and most likely the process of vitality reduction and death of its stands of various age is slowly coming to an end. Pine showed a systematic decrease in the radial increment during 1885-1994, and there were no distinct symptoms indicating a change of this unfavourable trend. Beech showed no significant decrease in the radial increment during 1885-1994. In the Świętokrzyski National Park the differences in the radial growth between younger and older generations were noticeable only in the case of beech. The radial growth of trees of different ages was very similar in the case of fir and pine.