Climate signals in tree-ring chemical components of Cedrela fissilis Vell. growing in Brazilian Amazon
Chemical traits of tree-rings are sparsely used for dendroclimatic analysis. The difficulty of the laboratory process to obtain these proxies and understand their physiological relationship with meteorological variables have limited the development of dendrochemistry in tropical forests. Here, we show the first Micro X-ray fluorescence (µXRF) time series of chemical elements from Cedrela fissilis trees growing in southern Brazilian Amazon. We assess the relationships among wood traits (widths, density and chemical composition) and local and regional climate. Fourteen radii were selected from a tree-ring width chronology and dated by radiocarbon to be then X-rayed by Itrax Multiscanner at DendrOlavide. We tested the responses of annual ring width (RW), ring density (RD), and relative concentrations of Sulfur (S), Potassium (K) and Calcium (Ca) to precipitation and temperature. The mean between-trees correlation of indexed values (rbt) for RW, RD, S, K and Ca is 0.51, 0.48, 0.27, 0.31 and 0.21, respectively. The K concentrations enhances at the beginning of the wet season precipitation (November-1 to December-1, r= 0.43), RW at the middle of the wet season (February to March, r= 0.44), RD during late wet season (March to May, r= 0.30), and the S concentrations during the end of the dormancy season (August to October, r=0.46). While, Ca correlate with temperatures during the wet season (r= 0.52). We confirm the potential of long-term wood-chemistry studies based on the µXRF non-destructive technique for dendroclimatic studies in tropical regions. Grants 2020/04608-7, 2018/22914-8 and 2017/50085-3, Sao Paulo Research Foundation (FAPESP).