Influence of the El-niñio southern oscillation on cambial growth of Cedrela fissilis Vell. in tropical and subtropical Brazil

The width of the increment zones in the xylem of Cedrela fissilis Vell was investigated by dendrochronological methods on a tropical (10°09'S, 59°26'W) and a Subtropical site (25°15'S, 50°45'W) in Brazil as to study the relationship between the El-niñio southern Oscillation (ENSO) and the cambial growth of this species. Treering width chronologies were deveoped for both sitesfrom crossdated increment curves. Simple correlations were computed between the southern oscillation index (SOI), meteorological records, and the annual increment of Cedrela. On the tropical site the annual increment of Cedrela was correlated with the precipitation from March to May of the previous growth period. while on the subtropical site the annualincrement was correleted with the temperature in May of the previous growth period and in November of the current growth period. On the tropical site reduced precipitation from March to May was correlated with low SOI values (El-niñio) in March and April. On respectively. On the tropical site 57% and on the subtropical site 53% of the variability of the annual increment of Cedrela was due to precipitation and temperature anomalies related to ENSO. This show that on both sites to a certain amount the variability of cambial growth of Cedrela is related to ENSO, but tree ring chronologies of Cedrela alone are not secure proxy data for the reconstruction of El-niñio events.