Impact of Climate, Stand Growth Parameters, and Management on Isotopic Composition of Tree Rings in Chestnut Coppices

Research Highlights: Chestnut trees' (Castanea sativa Mill.) growth and their responses to climate are influenced by stand-characteristics and managements. This study highlighted that chestnut tree-ring growth is not particularly influenced by climate, while minimum temperature showed a positive relation with both intrinsic water-use efficiency (WUEi) and delta O-1(8). Background and Objectives: The aim is to check the responses of chestnut trees to climate conditions and the role of stand structure and management. Materials and Methods: Stands with 12-14-year-old shoots were studied using dendrochronological and isotopic (delta O-18 and delta C-13) approaches. Correlations with climate parameters were investigated and principal component analysis was performed using site-characteristics and tree growth parameters as variables. Results: Correlations between tree-ring width (TRW), tree-ring delta O-18, and delta C-13-derived intrinsic water-use efficiency (WUEi) revealed stand-dependent effects. The highest Correlations were found between climate and tree-rings' isotopic composition. Chestnut was sensitive to high-minimum temperature in March and April, with a negative relationship with TRW and a positive relationship with WUEi. delta O-18 signals were not significantly different among stands. Stand thinning had a positive effect on WUEi after 1-2 years. Stand competition (indicated by shoots/stump and stumps/ha) positively influenced both WUEi and delta O-1(8).