Dendroclimatological potential of the Australian red cedar

We examined Toona ciliata M.Roemer (Australian red cedar) for its potential to deliver annually resolved tree-ring proxy data. Such proxies are valuable and sought-after sources for reconstructing climate beyond instrumental records, especially in Australia. T. ciliata was chosen because it is one of the few deciduous tree species in Australia experiencing a seasonally dormant period of the cambium. This was confirmed by a preliminary tree-ring analysis which revealed distinct growth rings. Because of initial uncertainties regarding reliable annual growth rings in the wood of T. ciliata, a dendrometer-band study was conducted in addition to the tree-ring analysis. Stem increments revealed a common period of dormancy during winter and the measurements were found to correlate with both precipitation and temperature, depending on the site. For the first time, our tree-ring analysis demonstrated that samples from different individuals can be cross-dated and the resulting site index from Upper Kangaroo Valley (New South Wales) has the potential to reconstruct early season temperatures and late-season rainfall.