The paper presents the dendrochronological analysis of silver firs (Abies alba Mill.) growing in the canopy layer of the forest stands. We searched for the similarities in the rhythm of radial growth of studied trees and we analysed the response of these stands to the increment disturbances related to the occurrence of adverse climatic factors and the pressure from industrial pollution. The research material was collected in 30 pure and uneven−aged silver fir stands located in the Świetokrzyskie Mountains (central Poland). We investigated the effect of age of the stands and the conditions for their growth (location, forest habitat type) on an average tree−ring width. In order to detect similarities in the rhythm of radial growth of the surveyed stands, we grouped the raw chronologies by the means of the cluster analysis, using Ward's agglomeration procedure with 1−r distance (r – Pearson correlation coefficient). We assessed the incremental response of the investigated stands to the disturbances (situations of significantly reduced radial growth) using indicators of resistance, recovery and resilience proposed by Lloret et al. [2011]. We also studied the influence of the stand age and the forest habitat type on the response of analysed for stands to the detected disturbances. The shortest chronology consisted of 94 tree−rings, while the longest one of 137. Average length of the obtained silver fir chronologies was 119 years. Older fir stands characterised with narrower rings (r=–0.451, p=0.012). Neither the location, nor the forest habitat type are the factors determining the similarity of the rhythm of radial growth of silver firs from the Świętokrzyskie Mountains (p=0.243 and p=0.967 respectively). The extreme climatic conditions responsible for the majority of the short−term (one−year−long) incremental depressions are the factor of regional importance, which affects the growth of investigated trees. Older stands characterized with better possibilities of increment recovery after the disturbance than younger stands (p<0.001), which may be a result of the production of secondary crowns. No consistent differences in the indices of resistance and resilience were found among analysed stands.
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