Temperature effect on size distributions in spruce-fir-beech mixed stands across Europe

• DOI: 10.1016/j.foreco.2021.119819
• Publication Date: 2021-11-03T03:57:39Z
• Authors: Sonia Condés; Miren del Río; David I. Forrester; Admir Avdagić; Kamil Bielak; Andrej Bončina; Michal Bosela; Torben Hilmers; Aida Ibrahimspahić; Stanisław Drozdowski; Andrzej Jaworski; Thomas A. Nagel; Zuzana Sitková; Jerzy Skrzyszewski; Roberto Tognetti; Giustino Tonon; Tzvetan Zlatanov; Hans Pretzsch
• Keywords: podnebje; 0106 biological sciences; info:eu-repo/classification/udc/630*111; Diameter distribution; diameter distribution; inter-specific competition; Climate; matrični modeli; mountain forest; premer; Matrix model; 01 natural sciences; gorski gozdovi; drevesna rast; ddc:630; Basal area growth; climate; matrix model; 15. Life on land; ddc:; basal area growth; 13. Climate action; Inter-specific competition; Mountain forest

Forest composed of Picea abies L., Abies alba Mill. and Fagus sylvatica L. cover a large area in the European mountain regions and have a high ecological and socio-economic importance as they supply many ecosystems services. Because of climate change, these forests are exposed to warming, and this effect increases with elevation, which may impact their delivery of goods and services. Previous studies did not find significant changes in the overall productivity of these species over the last 30 years, but they observed changes in species competitiveness at the species and tree levels. In this study, we aimed to link previous results on tree, species and stand level growth in spruce-fir-beech mixed mountain forests by analysing species size distribution dynamics under different climate conditions and their effect on stand growth. We developed a matrix model based on data from 76 long-term experimental plots distributed throughout Europe. We used the change in stand basal area to explore whether temperature modifies species size dominances and proportions, whether the temperature effects on changes in species basal area depend on species size dominance, and whether the effect of species size dominance on changes in the stand basal area varies with temperature. Our results showed that annual mean temperature is an important climatic driver of species dynamics in spruce-fir-beech mixed mountain forests, such that stand basal area growth was favored by higher temperatures, particularly due to positive responses of silver fir which were greater than negative effects of temperature on European beech. The high temperatures also favored the size-dominance of silver fir, while European beech tended to have smaller diameters, independent of the temperature. We also found that the identity of the size-dominant species also influenced changes in stand basal area, with the highest or the lowest changes when Norway spruce and European beech were the size-dominant species, respectively. Silver fir was less influenced by the identity of the size-dominant species than by temperature. Therefore, although mixed mountain forests of spruce-fir-beech were found to be resilient systems in terms of stand productivity, we conclude that increasing temperatures may modify species dynamics and consequently silvicultural interventions will be needed to control species proportions and dominances.