Small plants and their importance in the construction of long annual growth ring chronologies for paleoenvironmental studies

FIDEL A. ROIG

Goias

Congreso; 71 Congresso Nacional de Botanica; 2021

UFG

Knowledge of the Earth´s past climate represents the only means of assessing climate variations before man-made climate change. The IPCC has indicated the importance of studying the paleoclimate of the last two thousand years, by virtue of the fact that in this period marked climatic events have been registered on a regional to global scale. Tree rings are natural archives widely used for documenting the climate history in a high-resolution time scale. Thus, extra-long tree-ring chronologies are so much appreciated to extend our appraisal of changes in climate during periods far beyond the instrumental records. Interesting, has been the recent discovery of trees that regularly do not exceed 2-3 m in height, which reach ages several times a hundred years old. These trees are confined to places with low moisture availability, which in turn facilitates the preservation of dead wood for centuries. Through statistical climate/growth calibrations it was possible to reconstruct the pluvial history in northern Patagonia for the last millennia. Results indicate fluctuations in coincidence with Late Holocene climate events. In addition, these small plants allowed us to recognize that characteristics of the 20th century climate, are distinctive. Comparisons with other reconstructions complete a regional view of climate variability.