Climate change, forests, and agricultural sustainability in Northwestern Argentina: a dendroecological perspective

M.E. FERRERO; N.I. GASPARRI; R. VILLALBA

Vancouver BC, Canadá

Conferencia; First American Dendrochronology Conference, AmeriDendro2008; 2008

University of British Columbia

During the last three decades a steady increase in soybean production has changed the economic scenario in Argentina, turning soybean into the main export product and consequently, the mayor income of current economy. The expansion of soybean has been facilitated, among other factors, by a period of abundant precipitations starting in 1970?s, which has allowed the soybean culture to extend in areas formerly drier and non-suitable to cultivation. This has led to unprecedented clearings of the subtropical dry forests in the Chaco region of Argentina (South America) during the past decades. Tree-ring chronologies from subtropical dry Chaco (22-26 °S) have recently been developed from hardwood species new in dendrochronology. Although the Schinopsis lorentzii chronologies show the occurrence of rainfall oscillations during the past 200 years, the most recently cycle of increased precipitation in the subtropical region of Northwestern Argentina is unusual in the context of past climatic variability. Tree-ring and instrumental records shows that the interval of abundant precipitation is still going on, however, some dry events in recent years suggest that the wet period is approaching to its end.  Current land-use changes will be threatened under future conditions of reduced precipitation. Based on the long term record provided by tree-rings we evaluate the temporal extent of the recent wet oscillation, question the soybean sustainability, and point out the ecological impacts of the recent environmental changes in northwestern forests of Argentina.