El Niño Southern Oscillation Signal in World Highest Elevation Tree-Ring Chronologies from the Altiplano Plateau at 4,600 m a.s.l.

DUNCAN A. CHRISTIE; ANTONIO LARA; JONATHAN BARICHIVICH; RICARDO VILLALBA; MARIANO S. MORALES; EMILIO CUQ

Riga, Letonia

Conferencia; VI Annual Conference of the European Association for Tree-Ring Research (ATR), Tree-rings in Archeology, Climatology and Ecology (TRACE); 2007

University of Latvia, Latvian Dendroecologist Society

El Niño-Southern Oscillation (ENSO) is the largest source of inter-annual variability operating in the earth´s climate system, and is associated with extreme weather conditions having large social, ecological and economic impacts. Several tree-rings records have been utilized to reconstruct past ENSO variability but none of them comes from South America. On the Altiplano plateau in the central Andes are located the world highest elevation forest composed by Polylepis tarapacana trees 4,000-5,000 m a.s.l. We use two tree-ring chronologies in order to analyze the regional climate and ENSO influences on P. tarapacana growth at the east and west Andean slopes on the Altiplano. P. tarapacana growth has a strong common signal and a complex relation with summer temperature and precipitation. Ring-width has an inverse relation with temperature respect to precipitation. Temperature has a positive and negative influence on ring-width during current and previous summer, respectively. Tree-growth is positively correlated with spring-summer tropical Pacific SSTs, with a spatial pattern resembling to ENSO wedge. In general the El Niño (La Niña) events are well recorded in the chronologies, determining above (below) mean anomalies on tree-growth. P. tarapacana chronologies offer a good opportunity to future multi-proxy ENSO reconstructions.