Growth Assessment Of Native Tree Species From The Southwestern Brazilian Amazonia By Post-Ad 1950 C-14 Analysis: Implications For Tropical Dendroclimatology Studies And Atmospheric C-14 Reconstructions

Tree-ring width chronologies of cedro (Cedrela fissilis Vell.) (1875 to 2018), jatoba (Hymenaea courbaril L.) (1840 to 2018) and roxinho Peltogyne paniculata Benth.) (1910 to 2018) were developed by dendrochronological techniques in the southern Amazon Basin. Acceptable statistics for the tree-ring chronologies were obtained, and annual calendar dates were assigned. Due to the lack of long-term chronologies for use in paleoclimate reconstructions in degraded forest areas, dendrochronological dating was validated by C-14 analysis. Tree-rings selected for analysis corresponded to 1957, 1958, 1962, 1963, 1965, 1971, and 1972. Those are critical calendar years in which atmospheric C-14 changes were the highest, and therefore their tree-ring cellulose extracts C-14 signatures when in alignment with existing post-AD 1950 atmospheric C-14 atmospheric curves would indicate annual periodicity. Throughout our correlated calendar years and post-AD 1950 C-14 signatures, we indicate that H. courbaril shows an erratic sequence of wood ages. The other two tree species, C. fissilis and P. paniculata, are annual in nature and can be used successfully as paleoclimate proxies. Moreover, due to the sampling site's strategic location in relation to the Tropical Low-Pressure Belt over South America, these trees can be used to enhance the limited amount of observational data in Southern Hemisphere atmospheric C-14 calibration curves.