A composite, 290‐year tree‐ring δ13C chronology was developed from a site in Chile where 5 Fitroya cupressoides (alerce) trees were sampled, 2 increment cores per tree, and the holocellulose component was analyzed in 5‐year ring groups. This chronology shows a decreasing δ13C trend of approximately 1.2‰, primarily since the turn of this century. This δ13C decline is similar to that of major tree‐ring studies in the Northern Hemisphere, but it is the only major Southern Hemisphere study which clearly exhibits such a δ13C trend. This is the first evidence for any interhemispheric reproducibility of tree‐ring δ13C chronologies, and furthermore, the Fitzroya δ13C trend conforms well to that of δ13C of atmospheric CO2 determined from ice cores and direct measurements. This correspondence suggests the alerce δ13C trend has not been substantially influenced by systematic changes in environmental factors such light, relative humidity and soil moisture or by changing atmospheric CO2 concentration, all of which are, in theory, capable of altering Ci/Ca ratios and obscuring the atmospheric δ13C record contained in the tree rings.
|Original language||English (US)|
|Number of pages||6|
|State||Published - 1994|
ASJC Scopus subject areas
- Atmospheric Science