Abstract

Dendrochronological data in diverse regions is more available each year, yet subtropical humid climates remain under-represented. This study addresses the dendrochronological potential of native species Neltuma affinis and Neltuma nigra, in subtropical humid savannas of northwestern Uruguay. Three ring-width chronologies from three sites are presented, using 80 series and 41 trees. Annual growth between 1901 and 2008 was compared to climate variability including precipitation, maximum temperature, Standardized Precipitation-Evaporation Index (SPEI), Southern Annular Mode and the South American Drought Atlas (SADA). Chronologies displayed an Expressed Population Signal ranging from 0.82 to 0.93. Growth was positively correlated with precipitation for the two N. affinis chronologies located at 39–62 masl (r = 0.30***; r = 0.37***), and negatively correlated for the N. nigra chronology located at 7–27 masl (r = -0.30**). Similarly, both N. affinis chronologies had a positive correlation with SPEI (r = 0.29**; r = 0.41***) and a negative correlation with maximum temperature (r = - 0.31***; r = -0.48***), while a negative correlation with SPEI (r = -0.21**) and a positive correlation with maximum temperature (r = 0.23**) was found for N. nigra. Species-specific soil preferences may influence these contrasting responses, where N. affinis populations thrive in drainable soils and N. nigra occurs exclusively in flood-prone halomorphic soils, highlighting the role of topography in growth response to climate. This study contributes new data to the growing South American dendrochronological network, enhancing our understanding of growth drivers in savanna woodlands in Uruguay and similar subtropical humid climates.