CONICET | Buscador de Institutos y Recursos Humanos

Record rainfall totals have recently been recorded over the Amazon Basin and may be part of an amplified cycle of wet to dry season precipitation and streamflow. Just how unprecedented these recent hydroclimatic changes might be in the context of natural climate variability over the Amazon is difficult to determine from the short, sparse, and often-interrupted instrumental observations of precipitation that begin mostly in the mid-to late-20 th century. High-resolution paleoclimate reconstructions may help identify low frequency variability in Amazon hydroclimate and would provide a useful framework for the evaluation of modern trends and changes in extremes. In spite of the high biodiversity of Amazonian forests, only a few native tree species have been proven to form reliable annual rings and even fewer have produced exactly dated tree-ring chronologies of sufficient length to have value for climate reconstruction. A new tree-ring chronology of Cedrela odorata extending from 1759-2016 has recently been developed in the Rio Paru sector of the eastern Amazon. This chronology confirms the exact dating and precipitation response of the first well-replicated Cedrela chronology developed from a separate location on the region. During the last 40-years when rainfall has been widely recorded, positive and especially negative growth extremes in the new Rio Paru Cedrela chronology have been associated with above and below average precipitation at many instrumental stations across the Amazon Basin. The derived rainfall reconstruction exhibits significant 40-year linear trends in wet season precipitation totals. This strong multi-decadal component of reconstructed precipitation for the Rio Paru region suggest that the observed recent increases in precipitation may not be entirely unprecedented over the eastern Amazon Basin in the context of natural variability