Progress in dendroclimatic Studies in Indonesia

Abstract

A 416-year (1514-1929) tree-ring width chronology of teak (Tectonagrandis L. F.) from Cepu, Central Java, Indonesia (111¢X35¡¦E, 7¢X06¡¦S), first published by Berlage over 60 years ago, remains one of the few high-resolution paleoclimatic archives available for the western equatorial Pacific. Here we present an update of this chronology from 1880-1991, which extends the original series by 63 years. As was found for the original Berlage record, the updated chronology is correlated positively with rainfall and inversely with sea level pressure during the dry monsoon season (around May to October) just prior to the period of growth in Java. This teak record is also related to several indices of the El Nino-Southern Oscillation (ENSO), including sea level pressure at Darwin, Australia, Wright¡¦s rainfall index for the equatorial Pacific, and the Quinn historical record of ENSO. The years 1737 and 1925, rated as strong ENSO events by Quinn, are ranked among the three lowest index years in the Berlage teak record. 1967, which is not considered to be an ENSO year, has the lowest ring width index in the updated series from 1880-1991, and the lowest dry season rainfall on record for Jakarta, Indonesia (since 1869). The dry monsoon drought during the extreme 1982-83 ENSO event (although devastating for much of Indonesia) was not unusually severe based on either the tree-ring or Jakarta rainfall records.

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