Tree growth and hydrology in Southeastern South America: how tree rings reveal the history of climate and streamflow in Uruguay

Category: Time:
Wednesday, March 29, 2023 - 12:30 to 14:30
Room: URL: Speaker:
Christine Lucas
LTRR Haury Fellow
Kiyomi Morino

Tree-ring research is expanding into savanna and grassland biomes, where trees are a relatively scarce yet valuable source of historical data on climate history. In the Southeastern South American country of Uruguay, we developed the country’s first tree-ring chronologies to examine how tree growth responds to hydroclimate variability.  We show how annual tree ring growth in native tree species responds to seasonal precipitation, and how tree rings register major droughts and floods in Uruguay since the early 1900s.  We also show how broader networks of tree-ring data from long-lived trees in Central Chile can be used to reconstruct historical streamflow data in Uruguay, via shared responses to global climate phenomena. Recent research using native mesquite, Neltuma spp., shows how the same species can display opposite responses to precipitation depending upon site-specific characteristics. Finally, we present future directions for research including tree dating in urban cemeteries and in sunken logs from the Uruguay River, as well as the application of stable isotopes to detect historical drought. Uruguay is currently emerging from one of the worst regional droughts in recent history; and yet overall, the region has one of the most pronounced increases in summer rainfall worldwide in the past 100 years.  This talk shows how tree-ring data from native forests – which cover a mere 5% of the country – contribute to a broader understanding of hydrological and climate variability in this grassland-dominated, agricultural landscape of southeastern South America.

Note the time and venue, which are different from most talks in this series.