1. Spatiotemporal variability of dendroecological indicators in pedunculate oak (Quercus robur L.) tree-rings across Europe in relation to species distribution modelsAndrei Popa, Jernej Jevšenak, Marcin K. Dyderski, Radosław Puchałka, Allan Buras, Ionel Popa, Martin Wilmking, Aleksandra Kalisty, Catalin Constantin Roibu, Marcin Jakubowski, 2025, izvirni znanstveni članek Povzetek: Climate is a primary, but non-stationary, driver of tree growth. Climate change is altering the sensitivity of forest growth to water availability and temperature over time. It is considered that pedunculate oak (Quercus robur L.) will cope with the changing climatic conditions in Europe in the near future. However, while species distribution models project expansion zones, they also identify reductions in occurrence at the dry and warm distribution margins. Whereas species distribution models primarily rely on occurrence data, tree rings—given their long-term perspective and their use in empirical models—can provide a mechanistic view of forest growth dynamics, including temporally changing climate responses. Increased climate sensitivity and growth synchrony are key dendroecological indicators of tree stress. Here, we used an unprecedented network of 150 Q. robur sites (over 3300 trees), covering the full projected range of contracting to persistent areas across Europe, to assess the dendroecological indicators over recent decades in relation to species distribution model predictions. We reveal that oaks in areas projected to experience range contraction exhibited greater sensitivity to current growing season climatic conditions, whereas those in persistence areas responded more strongly to previous season conditions. Growth synchrony among trees was higher in the contraction areas, but showed no significant increasing trend over the last 70 years, as expected from ecotone theory. Temporal shifts in climate sensitivity were stronger for temperature and vapor pressure deficit in the persistence areas, whereas the climatic water balance gained importance in the contraction zones. These findings suggest that Q. robur growth is not yet being severely affected by climate change, and that the species is currently coping well with the climate changes, even in regions with projected range contractions, thereby challenging statistically derived scenarios of range shift based on species distribution models.
Ključne besede: climate change scenarios, climate–growth relationships, climatic water balance, growth synchrony, range contraction, vapor pressure deficit
Objavljeno v DiRROS: 04.11.2025; Ogledov: 320; Prenosov: 154
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2. Temperature-driven shifts in spatiotemporal stability of climate-growth responses of Douglas-fir (Pseudotsuga menziesii) from the southern Baltic Sea regionMarcin Miroslav Klisz, Radosław Puchałka, Mariusz Gławenda, M. Koprowski, Roberts Matisons, Sandra Metslaid, Aleksei Potapov, Tobias Scharnweber, Eric Andreas Thurm, Rita Verbylaite, Adomas Vitas, Martin Wilmking, Jernej Jevšenak, 2025, izvirni znanstveni članek Povzetek: The southern Baltic region spans a significant part of the European continent with its forests under significant pressure due to climate changes. The implications of these changes are crucial for both native and non-native tree species. Under future climate scenarios, most native conifer populations might lose their climatic optima in the region. In contrast, for non-native Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), climatic conditions are expected to become optimal in the Baltic Sea region. Therefore, understanding the acclimatisation trajectory of Douglas-fir over the last century is essential to assess its potential to supplement retreating species and reduce pressure on local habitats. To study the region-wide acclimatisation in the secondary distribution, we established a network of 27 Douglas-fir tree-ring chronologies along the south Baltic Sea. We determined the spatio-temporal stability of the climate signal in tree rings and the potential coastal effect on the plasticity of the growth response. We found a region-wide trend of climate-growth relationships, with a dominant effect of the early-growth season temperatures being more pronounced for mature than young stands. Sites with higher mean annual temperatures exhibit a stronger positive temperature–growth correlation, demonstrating the sensitivity of Douglas-fir to climate warming. Douglas-fir could serve as a more heat-tolerant alternative to the declining European species of the Pinaceae family and contribute to the preservation of functionally comparable coniferous forest communities. However, forest practitioners should be aware that Douglas-fir may alter habitat conditions affecting microclimate and influencing species diversity.
Ključne besede: climate warming, climate–growth relationships, dendroecology, Europe, tree growth
Objavljeno v DiRROS: 09.07.2025; Ogledov: 522; Prenosov: 403
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3. In pursuit of change : divergent temporal shifts in climate sensitivity of Norway spruce along an elevational and continentality gradient in the CarpathiansAndrei Popa, Jernej Jevšenak, Ionel Popa, Ovidiu Badea, Allan Buras, 2024, izvirni znanstveni članek Povzetek: Across much of Europe, climate change has caused a major dieback of Norway spruce (Picea abies L.), an economically important tree species. However, the southeasternmost fringe of this tree species – the Eastern Carpathians – has not yet suffered large-scale dieback. Studying temporal shifts of climate sensitivity (TSCS) over time may elucidate the degree to which Norway spruce may be vulnerable to climate-change induced decline in upcoming decades. Under this framework, we analyzed a regional tree-ring network comprising >3000 trees, with the aim of quantifying TSCS since 1950. We mathematically defined TSCS as the slope parameter of the regression of climate sensitivity (the correlation coefficient) over time. Given the often-observed contrasting shift of climate sensitivity at low versus high elevations, we were particularly interested in studying potentially divergent TSCS along elevational and spatial gradients. Our analyses revealed several indications of TSCS for Norway spruce in the Eastern Carpathians. First, at high elevations (>1100 m a.s.l.), we found that the positive link between summer temperature and spruce growth decreased significantly over the study period. In turn, these trees, over time, featured an increasing positive relationship with late winter temperatures. At low elevations (<800 m a.s.l.), the signal of positive summer Standardised Precipitation-Evapotranspiration Index (SPEI) correlation became more frequent among sites towards 2021, while the strength of the positive winter SPEI correlation from the previous growing season weakened. Our results revealed that TSCS was driven significantly by an elevational climate gradient and a longitudinal continentality gradient. Overall, our findings indicate that Norway spruce is increasingly affected by water limitations under climate change at low elevations, highlighting a potentially rising risk of decline of this species in the Eastern Carpathians.
Ključne besede: temperature, water availability, climate change, tree-ring width, non-stationarity, Picea abies, daily climate-growth relationships
Objavljeno v DiRROS: 30.09.2024; Ogledov: 1017; Prenosov: 1072
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4. Daily climate data reveal stronger climate-growth relationships for an extended European tree-ring networkJernej Jevšenak, 2019, izvirni znanstveni članek Povzetek: An extended European tree-ring network was compiled from various sources of tree-ring data from Europe, northern Africa and western Asia. A total of 1860 tree-ring chronologies were used to compare correlation coefficients calculated with aggregated day-wise and month-wise mean temperature, sums of precipitation and standardised precipitation-evapotranspiration index (SPEI). For the daily approach, climate data were aggregated over periods ranging from 21 to 365 days. Absolute correlations calculated with day-wise aggregated climate data were on average higher by 0.060 (temperature data), 0.076 (precipitation data) and 0.075 (SPEI data). Bootstrapped correlations are computationally expensive and were therefore calculated on a 69.4% subset of the data. Bootstrapped correlations indicated statistically significant differences between the daily and monthly approach in approximately 1% of examples. A comparison of time windows used for calculations of correlations revealed slightly later onset and earlier ending day of the year for the daily approach, while the largest differences between the two approaches arise from window lengths: Correlations calculated with day-wise aggregated climate data were calculated using fewer days than the monthly approach. Differences in the onset and ending dates of periods for the daily and monthly approaches were greater for precipitation and SPEI data than for temperature data.
Ključne besede: tree rings, dendroclimatology, tree-ring network, daily climate data, climate-growth relationships, dendroTools
Objavljeno v DiRROS: 21.08.2019; Ogledov: 3405; Prenosov: 1847
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