The climate reconstruction potential of Acacia cambagei (gidgee) for semi-arid regions of Australia using stable isotopes and elemental abundances

- Multi-centennial, annually-resolved records of climate for arid and semi-arid areas of Australia are rare.
- Here we use a stable isotope and x-ray fluorescence approach to dendrochronology in Acacia cambagei.
- Significant relationships exist between δ18O of α-cellulose and rainfall, temperature and drought in February and March.

To provide multi-centennial, annually-resolved records of climate for arid and semi-arid areas of Australia it is necessary to investigate the potential climate signals in tree species in this large region. Using a stable isotope and x-ray fluorescence approach to dendrochronology in Acacia cambagei, this study demonstrates short (10 years) proxies of temperature and precipitation are possible. Because rings in A. cambagei are difficult to see, precluding traditional dendrochronology, we used elemental abundances of Ca and Sr as an annual chronometer back to 1962. Radiocarbon analysis confirmed that our dating of wood from two trees. We compared δ13C and δ18O from the α-cellulose of the dated wood over the most recent 10 years (n = 10) to local climate records demonstrating significant relationships between δ18O and precipitation (r = −0.85, p < 0.002); mean monthly maximum temperature (r = 0.69, p < 0.03); and drought indexes (CRU scPDSI 0.5°, r = −0.89, p < 0.001) for February and March. Acacia cambagei may be useful in developing regional networks of climate proxies for drought. Using modern trees, in combination with architectural timbers, it may be possible to construct a multi-century, annually-resolved proxy-record of rainfall and temperature for semi-arid north-eastern Australia.