Looking for a drought-tolerant tree species among native and introduced mountain conifers

Understanding species-specific adaptations to climate change, which exacerbates drought stress and heat waves, is crucial for sustainable forests. This knowledge can help in selecting potential alternatives for species such as Norway spruce (PIAB), which faces significant dieback in Central European forests. In this study, we focused on the adaptive capacity under novel climate of native silver fir (ABAL) and alien Douglas-fir (PSME) as potential alternatives for the most threatened old spruce stands in the Sudetes (Poland). We applied dendrochronological approach to track tree growth dynamics over the last 70 years and quantified how species resisted and recovered from the extreme drought events of 2003 and 2015. Our results revealed the highest potential to adapt to climate change manifested by ABAL. It displayed not only lower sensitivity to precipitation shortages but it also showed greater resilience and resistance to extreme drought compared to the remaining species. In addition, both ABAL and PSME could benefit from extended growing seasons. On the other hand, the non-native PSME outperformed both native species in terms of growth rate. However, it was similarly sensitive to summer precipitation as PIAB and showed low drought tolerance. Our findings supports a better understanding of species-specific differences in their adaptive potential and can help forest managers make informed decisions about species selection for climate change-adapted future forest.