Dendroclimatologia na Amazônia: sinais climáticos em cronologias de largura de anéis e δ¹⁸o em Cedrela odorata

Abstract

The Amazon Basin is one of the most important regions for regulating regional and global climate. Over recent decades, the region has experienced increasingly frequent climate extreme events. However, climate data for the Amazon are relatively recent (< 100 years) and sparsely distributed spatially, which hampers the assessment of anthropogenic effects on natural climate variability. In this context, tree rings constitute important natural archives capable of filling the gap in long-term climate perspectives in the region. Accordingly, the objective of this thesis was to develop centennial chronologies of tree-ring width and oxygen isotopes from Cedrela odorata across the Amazon Basin. Three tree-ring width chronologies and one oxygen isotope chronology were developed. Series dating was performed through cross-dating and validated using radiocarbon dating. Three chronologies were successfully validated, including two treering width chronologies and one oxygen isotope chronology. The validated tree-ring width chronologies did not exhibit consistent climatic correlations, highlighting the complexity of climate–growth relationships in the Amazon Basin. In contrast, the oxygen isotope chronology showed a strong relationship with the hydrological regime of eastern Amazonia, enabling precipitation reconstruction. Overall, the results indicate that tree-ring width records require additional physiologically based studies to better interpret the recorded signals, whereas oxygen isotopes represent a more promising approach for paleoclimate studies in tropical regions.