Modeling of Potential Distribution of Castanea sativa Mill. in Bolu Regional Directorate of Forestry Depending on Climate Variables

In this study, we assessed the potential impacts of climate change on Castanea sativa habitats using the MaxEnt model under SSP2-4.5 and SSP5-8.5 scenarios for 2050, 2070, and 2090 in the Bolu Regional Directorate of Forestry, northwestern Turkey. Bioclimatic and topographic variables were selected through ecological and correlation analyses. The model performed well, with AUC values of 0.961 (training) and 0.959 (test). Bio17 (precipitation in the driest quarter), Bio15 (precipitation seasonality), and Bio4 (temperature seasonality) were the most influential variables. Under SSP5-8.5, unsuitable areas slightly increase while high suitability areas decrease from 310.92 ha to 266.47 ha by 2090. SSP2-4.5 projects a greater reduction in high suitability (to 133.26 ha) and an increase in medium suitability areas, suggesting habitat transitions. C. sativa is currently found predominantly at elevations below 1000 meters, with 20.2% of suitable habitats located between 0–100 meters; in the future, the species is expected to shift to relatively lower elevations. These findings highlight the importance of adaptive forestry and conservation strategies to reduce habitat loss and fragmentation.