DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 7-8/2022 str. 53 <-- 53 --> PDF |
decreased from 1988 to 1991, then stagnated for a long time and increased in the last decade (Figure 7). In order to eliminate the influence of the so-called multicollinearity, i.e. intercorrelations between temperature and precipitation (higher precipitation causes lower temperatures and vice versa), which makes it difficult to draw reliable conclusions about the individual influence of these two climatic elements on tree growth, drought indices were used in the analyses of the climate impact on the tree ring formation. The FAI index and SPEI index were selected as suitable for this analysis. The obtained value of the correlation coefficient between the FAI index and the index of the tree-ring width, i.e. the chronology of Scots pine was - 0.46 (p < 0.00) and - 0.54 (p < 0.00) of Austrian pine. The SPEI index, which was developed to define and monitor drought conditions, has been increasingly used in dendrochronological research. In the period from June to September for Austrian pine and June-August for Scots pine, there was a strong and statistically significant dependence of the tree-ring width index on the SPEI index (calculated for a three-month time interval), i.e. lack of moisture had a significant influence on radial growth in the study period (Figure 8). The pointer year was defined as a year in which more than 90% of the series (in a sample of 10 or more individual tree- |