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We analysed climate change impacts on the growth and natural mortality of forest tree species and forest carbon (C) balance along an elevation gradient extending from the Pannonian lowland to the West Carpathian Mountains (Central Europe). Norway spruce Picea abies, European beech Fagus sylvatica, and oak Quercus sp. were investigated for 2 future time periods: 2021-2050 and 2071-2100. The period 1961-1990 was used as reference. Forest growth simulations were based on the SIBYLA tree growth simulator (an empirical model), and C cycle-related simulations were performed using BIOME-BGC (a process-based biogeochemical model). Growth simulations indicated that climate change will substantially affect the growth of spruce and beech, but not of oak, in Central Europe. Growth of spruce and beech in their upper distribution ranges was projected to improve, while drought-induced production decline was projected at the species' receding edges. Beech was the only species projected to decline critically at lower elevations. C cycle simulations performed for the zone of ecological optima of the 3 tree species indicated that these forests are likely to remain net carbon dioxide sinks in the future, although the magnitude of their sequestration capacity will differ. Increasing nitrogen deposition and atmospheric carbon dioxide concentration were projected to greatly affect the forest C cycle. A multi-model assessment based on SIBYLA and BIOME-BGC simulations performed for the zone of ecological optima suggested that oak production will either remain the same as in the reference period or will increase. Future production of beech seems uncertain and might decline, while spruce production is likely to increase. The results also confirmed the value of multi-model approaches for assessing future forest development under climate change.KEY WORDS: Norway spruce · European beech · Oak · Forest carbon cycle · Tree production · Tree mortality · BIOME-BGC model · SIBYLA tree growth simulator Resale or republication not permitted without written consent of the publisher

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14European beech (Fagus sylvatica L.) and Norway spruce (Picea abies Karst.) are two of the 15 most ecologically and economically important forest tree species in Europe. These two species 16 co-occur in many locations in Europe, leading to direct competition for canopy space. Foliage 17 characteristics of two naturally regenerated pure stands of beech and spruce with fully closed 18 canopies were contrasted to assess the dynamic relationship between foliage adaptability to 19 shading, stand LAI and tree growth. We found that individual leaf size is far more conservative 20 in spruce than in beech. Individual leaf and needle area was larger at the top than at the bottom 21 of the canopy in both species. Inverse relationship was found for specific leaf area (SLA), 22highest SLA values were found at lowest light availability under the canopy. There was no 23 difference in leaf area index (LAI) between the two stands, however LAI increased from 10.8 24 to 14.6 m 2 m -2 between 2009 and 2011. Dominant trees of both species were more efficient in 25 converting foliage mass or area to produce stem biomass, although this relationship changed 26 with age and was species-specific. Overall, we found larger foliage plasticity in beech than in 27 spruce in relation to light conditions, indicating larger capacity to exploit niche openings. 28 29