Analysis of growth rings of Terminalia oblonga: Chronology and its relationship with climatic factors in an Amazonian flooded forest in Peru

Dendrochronology has proven fundamental for studying climate change in tropical forests. This study assessed the dendrochronological potential of Terminalia oblonga, a common species in the eastern Amazon of Peru, and its response to local and large-scale climatic and hydrological variations. A 94-year chronology (1929–2022) was constructed through the analysis of growth rings from 16 trees, correlated with local climatic variables (precipitation and temperature) and oceanic atmospheric circulation indices such as the Atlantic Multidecadal Oscillation (AMO), Pacific Decadal Oscillation (PDO), and Western Hemisphere Warm Pool (WHWP). A negative correlation was observed between precipitation and growth, particularly in the months of February, August, September, October, and November, suggesting that excess water may inhibit the species' growth. In contrast, temperature showed a significant positive correlation throughout most of the year, indicating that higher temperatures favor the growth of T. oblonga. Significant correlations were also found between the growth of T. oblonga and the AMO and WHWP indices, particularly between July and September, suggesting a considerable influence of these atmospheric patterns. Additionally, sea surface temperature (SST) was significantly and positively correlated with the species' growth, especially in the tropical Atlantic. This indicates that warmer temperatures promote the development of T. oblonga. The El Niño-Southern Oscillation (ENSO) phenomenon was analyzed using four indices: El Niño 1 + 2, El Niño 3, El Niño 3.4, and El Niño 4. The El Niño 1 + 2 index exhibited the strongest correlation with T. oblonga growth, suggesting a more direct impact of the eastern Pacific region on local climate conditions. In contrast, the influence of PDO and TSA was less consistent over time, and excessive precipitation had a negative effect. These findings confirm the potential of T. oblonga as an indicator of climate change and highlight the importance of continuing research on the interaction between climate change and forest dynamics in the Amazon. This study provides a solid foundation for future research on sustainable forest management and climate reconstruction in the region.