Прегледај по Аутор "Stjepanović, Stefan"

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    Growth response of different tree species (oaks, beech and pine) from SE Europe to precipitation over time
    (Institute of Dendrology, Polish Academy of Sciences, 2018) Stojanović, Dejan B.; Levanič, Tom; Matović, Bratislav; Stjepanović, Stefan; Orlović, Saša
    Changing climatic conditions can have various consequences for forest ecosystems, from increasing frequencies of forest fires, ice and windstorm events to pathogen outbreaks and mass mortalities. The Standardized Precipitation Index (SPI) was chosen for the evaluation of drought impact on the radial growth of trees after extensive preliminary testing of various calculated monthly climate parameters from the CARPATCLIM database. SPI was calculated for periods between 3 and 36 months for different sites (lowland and mountainous parts of Serbia, Southeast Europe), from which Quercus robur, Q. cerris, Fagus sylvatica and Pinus sylvestris samples were acquired. Bootstrapped Pearson’s correlations between SPI monthly indices and radial growth of tree species were calculated. We found that 12-month SPI for summer months may be a good predictor of positive and negative growth of different species at different sites. The strongest positive correlations for five of six tree-ring width chronologies were between 12-month June and 14-month September SPI, which implies that high growth rates can be expected when the autumn of the previous year, and winter, spring and summer of the current year, are well supplied with precipitation, and vice versa (low precipitation in given period/low growth rates).
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    The Impact of Adverse Weather and Climate on the Width of European Beech (Fagus sylvatica L.) Tree Rings in Southeastern Europe
    (MDPI, 2018) Stjepanović, Stefan; Matović, Bratislav; Stojanović, Dejan; Lalić, Branislava; Levanič, Tom; Orlović, Saša; Gutalj, Marko
    European beech (Fagus sylvatica L.) is the most important deciduous tree species in Europe. According to different climate scenarios, there is a relatively high probability of a massive decline in and loss of beech forests in southern Europe and in the southern part of central Europe. Thus, the authors of this study explored the dynamics of tree diameter increments and the influence of extremely dry years on the width of tree rings. This study used dendroecological methods to analyze the growth and diameter increments of European beech trees at locations in Serbia and the Republic of Srpska. The sampling was conducted along the vertical distribution of beech forests, at five sites at the lower limit of the distribution, at five optimal sites of the distribution, and at five sites at the upper limit of the distribution. Long-term analyses indicate that dry conditions during a growing season can reduce tree-ring width, but a reduction in tree growth can be expected as a result of more than one season of unfavorable conditions. Low temperatures in autumn and winter and prolonged winters can strongly affect upcoming vegetation and reduce tree development even under normal thermal conditions during a growing season
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    The potential impact of climate change on the distribution of key tree species in Serbia under RCP4.5 and RCP 8.5 scenarios
    (2021) Miletić, Boban; Orlović, Saša; Lalić, Branislava; Đurđević, Vladimir; Vujadinović Mandić, Mirjam; Vuković, Ana; Gutalj, Marko; Stjepanović, Stefan; Matović, Bratislav; Stojanović, Dejan B.
    The survival of forest tree species within certain areas of their distributions is in question due to the increasing occurrence of disturbances and degradation processes in forest ecosystems due to climate change. The aim of this paper is to predict changes in the spatial distribution of the ten most important tree species in Serbia (European beech, Pedunculate oak, Austrian oak, Hungarian oak, Sessile oak, Narrow-leafed ash, Silver fir, Norway spruce, Black and Scots pine) using climate indices (Forestry Aridity Index, FAI and Ellenberg Quotient, EQ) with up-to-date climate observations (E-OBS, covering the time period 1990-2019) and projections of future climate conditions (RCP 4.5 and RCP 8.5 scenarios, split into two time periods 2041-2070, 2071-2100). The computation of the area under the receiver operating characteristic (ROC) curves has shown that both FAI and EQ have a “fair” to “excellent” ability to predict the occurrence of five out of ten species (European beech, Silver fir, Norway spruce, Black and Scots pine), with EQ having a slightly better predicting ability. EQ-based projections from mid (2041-2070) to late 21st century (2071-2100) under RCP 4.5 predict that reduction rates will not exceed 25%. Similar reduction rates are given by FAI-based projections until 2070, while rates increase to approximately 35% towards the end of this century. For RCP 8.5, FAI-based projections are significantly worse than EQ-based projections. Irrespective of the used index, projections until 2070 suggest that 55- 75% of existing habitats will remain intact. Towards the end of the century, however, our analysis indicate that 75-85% (EQ) to 90-100% (FAI) of the five analyzed species habitats, will be found outside of their current climate space.