The growth of past, present, and future forests was, is and will be affected by climate variability. This multifaceted relationship has been assessed in several regional studies, but spatially resolved, large-scale analyses are largely missing so far. Here we estimate recent changes in growth of 5800 beech trees (Fagus sylvatica L.) from 324 sites, representing the full geographic and climatic range of species. Future growth trends were predicted considering state-of-the-art climate scenarios. The validated models indicate growth declines across large region of the distribution in recent decades, and project severe future growth declines ranging from −20% to more than −50% by 2090, depending on the region and climate change scenario (i.e. CMIP6 SSP1-2.6 and SSP5-8.5). Forecasted forest productivity losses are most striking towards the southern distribution limit of Fagus sylvatica, in regions where persisting atmospheric high-pressure systems are expected to increase drought severity. The projected 21st century growth changes across Europe indicate serious ecological and economic consequences that require immediate forest adaptation.

Please cite this article as: Aldea, J., Bravo, F., Vázquez-Piqué, J., Rubio-Cuadrado, A., del Río, M., 2018. Species-specific weather response in the daily stem variation cycles of Mediterranean pine-oak mixed stands. Agric. For. [220][221][222][223][224][225][226][227][228][229][230] This is a PDF file of an unedited manuscript (post-print version) that has been accepted for publication . 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 15Corresponding author: Aldea, J. email: jorge.aldea@uva.es 16 Title page Highlights: Maximum daily radial variation for pine occurred in spring, but in summer for oak  Number of spring daily cycles with radial increment was higher for pine than oak  Species responded differently to air temperature according daily radial variation  Rain increased daily radial variation and cycle duration in both species  Water availability limited daily radial increment for both species 15Corresponding author: Aldea, J. email: jorge.aldea@uva.es 16 Abstract 17Climate change forecasts are particularly severe for the western Mediterranean Basin, 18 where rising temperatures and decreased precipitation could increase the frequency of 19 drought events. Understanding the specific weather drivers of radial variation in 20Mediterranean mixed forest stands will allow us to better predict the ecological and 21 production alterations that may result from climate change. Here, we studied species 22 differences in stem daily radial variation cycles and daily radial increment of 23Mediterranean pine-oak (Pinus pinaster-Quercus pyrenaica) mixed stands over three 24 *Manuscript Click here to view linked References climatically contrasted years (2012)(2013)(2014) at two sites with dissimilar drought 25 conditions. Our aim was to uncover differences in the weather drivers of daily radial 26 variation for the two co-existing species. High-resolution point dendrometers were 27 installed in dominant oak and pine trees, so that daily radial variation cycles were 28 analyzed. Linear mixed models were fitted to analyze species-specific response to 29 weather. Air temperature leads to radial stem-size changes in daily variation cycles with 30 different species responses. Precipitation increased daily radial variation and cycle 31 duration in the same way for both species. Daily radial increment and number of cycles 32 with increment phase during spring was mostly higher for pine than oak, and water 33 availability was the most important control factor for the phase mentioned. Differences 34 in species response to weather conditions may offset the usual low production of pure 35 oak coppice Mediterranean stands and highlight the role of mixed forests as a possible 36 adaptation strategy for climate change. 37 Highlights: 38 Maximum daily radial variation for pine occurred in spring, but in summer for 39 oak 40  Nu...

This is a PDF file of an unedited manuscript (post-print version) that has been accepted for publication.

Over recent decades, forest management in Europe has increasingly moved towards the emulation of natural dynamics. Natural dynamics in beech-oak forests leads to the formation of monospecific beech stands, the oak usually being excluded or restricted to sites with poor growing conditions. However, beech is more vulnerable than oak to drought and high temperatures. In this study, we examine whether climate change could attenuate the dominance of beech and improve the competitive capacity of oak in an old-growth temperate forest located in the "Picos de Europa" National Park, northern Spain. We used a dendroecological approach to reconstruct the competitive capacity of beech and oak and developed a projection for the 21 st century based on forecasted climate conditions under three different emission scenarios. Beech is the dominant tree species in the studied forest, where the disturbance regime has favored the replacement of oak by beech. In general oaks are older than beeches and most of the small trees are beeches. Our results show that this substitution process may weaken due to the vulnerability of beech to warmer and drier conditions. Climate change will benefit oak growth over beech over the course of the 21 st century, as was observed in the late 20 th century. However, the natural gap dynamic benefits beech due to its greater shadetolerance. Therefore, if the resilience of the ecosystem is to be increased, management strategies favoring oak regeneration are necessary given the better adaptation of oak to climate change.

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