Elevational shift of Carpinus betulus L. under the future climate change in northern Iran

Although there are concerns about the impact of climate change on forests, the impact of future climate change on tree species in the Hyrcanian forests has been less studied. The effect of climate change on the distribution of species usually leads to the movement of species to higher altitudes and latitudes. Hornbeam is the most abundant tree species in the Hyrcanian forests, which is distributed in a large part of northern Iran. In this study, the effect of climate change on the change of hornbeam species height using species distribution models are currently being studied under different climate change scenarios for 2050 and 2070. In this study, various statistics including TSS, AUC, KAPPA, Sensitivity and Specificity were used to evaluate the performance of species distribution models. According to the model evaluation criteria, the random forest model had a higher efficiency than other models in the distribution of hornbeam in northern Iran. The future prediction of species distribution models showed that climate change will have a negative impact on the distribution of hornbeam, which will significantly reduce the areas with the potential for the presence of this species under RCP2.6 and RCP8.5 in 2050 and 2070. The results showed that the hornbeam species currently has the greatest potential for presence up to an altitude of 1000m, but also expands to an altitude of 2500m and with climate change will have the greatest potential for presence at an altitude of more than 1000m. Although very complex mechanisms justify the distribution of tree species in mountainous areas, climate is one of the most important of these mechanisms and the results of this study can be a criterion for future planning in Hyrcanian forests.