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ŠUMARSKI LIST 7-8/2022 str. 55     <-- 55 -->        PDF

deficiency on radial growth of both tree species. Based on the research results related to the dieback of Siberian pine forests, Kharuk et al. (2013) conclude that the SPEI index is likely to be useful as an early warning indicator of climate-related mortality across forests in other areas and regions, especially those composed of drought-sensitive species.
The response of Austrian pine in the study area in terms of the dependence of radial growth on climate is similar to the response of Austrian pine in the surrounding countries, which are characterised by similar climate conditions. According to Miklić et al. (2021), dendrochronological research in the Northern Velebit National Park (Croatia) showed that the main limiting factor for the growth of Austrian pine trees was the lack of moisture in summer. The correlation between the chronology and the sum of summer precipitation from 1954 to 2015 was significant and positive (R = 0.60, p = 0.0099), which made the signal in the tree-ring width stable and thus suitable for the reconstruction of precipitation. Studies of the impact of temperature and precipitation on the growth of Austrian pine trees in Serbia showed that Austrian pine was in the given conditions very sensitive to summer precipitation. On the other hand, its growth varied much less with temperature variations (Stajić and Kazimirović 2018; Stajić et al. 2020). According to the study of the Austrian pine chronology for the area of the western Balkan Peninsula, i.e.​​ the Dinarides in Bosnia and Herzegovina (Poljanšek and Levanič 2012; Poljanšek et al. 2013), radial growth proved to be more dependent on temperature than precipitation. Different results here obtained can be explained by the fact that the study area in the Dinarides is at a significantly higher altitude than the study area in Zavidovići-Teslić area (the altitude is on average about 600 meters higher).
Unlike Austrian pine, research studies dealing with the dependence of Scots pine radial growth on the climate conducted in the neighbouring countries that are characterised by similar climate conditions, are few. Using the dendrochronological method, Bouriaud and Popa (2009) compared the influence of climatic parameters on radial growth of the three main conifer species in the Romanian Carpathians (Scots pine, Norway spruce, and Silver fir) in mixed stands. Scots pine was the most sensitive to precipitation and the series of Scots pine tree-rings widths could be used for climate reconstruction with an emphasis on precipitation.
Dendrochronological analysis of Scots and Austrian pine in the Słowinski National Park and neighbouring forests showed a positive effect of high air temperature in the winter months (December, February, and March) and a negative effect of air temperature in September of the previous year on the radial growth of Scots and Austrian pine. Growth responses to the temperature of the winter months and September of the previous year were similar in both pine species. A stronger correlation was found in the populations that grew in better sites. In contrast to temperature, precipitation had no significant effect (Kochanowski and Bednarz 2007). A comparative analysis of the influence of climatic parameters on the growth of Scots and Austrian pine trees in northwestern Poland showed that the two species differed in terms of the relationship between radial growth and climate, despite the significant agreement (harmonisation) of the formed chronologies. Scots pine showed high sensitivity to heat conditions in winter (especially in February) and early spring, while the sum of precipitation in the growing season was less important. In contrast, the cambial activity of Austrian pine largely depended on the sum of precipitation during the growing season (Cedro 2006). Unlike northwestern Poland where Scots pine is an autochthonous and Austrian pine an allochthonous species, in the study area of Zavidovići-Teslić, both species are autochthonous and stands in the investigated sites are of natural origin.
A total of six pointer years were identified in Scots pine and a same number of pointer years in Austrian pine in the period for which meteorological data were available. Of the six pointer years identified in Scots pine, four years or 66% match the pointer years (of the same sign) identified in Austrian pine. The identified pointer years in the Austrian pine chronology for the areas of the western part of the Balkan Peninsula, i.e. ​​the Dinarides in Bosnia and Herzegovina (Poljanšek et al. 2012) do not match the identified pointer years in this study (except 2000). As already mentioned, there is a significant difference between these studies in terms of the average altitude of the investigated sites.
Unlike the research that has shown that the climate signal is not strong enough if only the tree-ring width is observed and it is necessary to use other parameters of tree rings such as density, latewood width and isotope content (Trouet et al. 2012; Klesse et al. 2015; Levanič et al. 2020), the series of tree-ring width indices obtained in this research had a favourable climate signal, especially the drought signal in the summer months.
The analysis of Scots and Austrian pine tree growth, which aimed to determine the similarity of growth patterns of these two tree species and the nature of the impact of climatic parameters on tree growth patterns, was conducted in the Zavidovići-Teslić area using data obtained at five sites. Based on the analysis of the presented characteristics and dendrochronological-statistical parameters of the series of tree rings, it was concluded that the data represent a good material for the development of site chronologies. The obtained local chronologies had quite similar growth patterns and there was a statistically significant agreement