Large-scale temperature inferences from tree rings: A review

This paper is concerned with dendroclimatic research aimed at representing the history of very large-scale temperature changes. It describes recent analyses of the data from a widespread network of tree-ring chronologies, made up of ring width and densitometric measurement data spanning three to six centuries. The network was built over many years from trees selected to maximise their sensitivity to changing temperature. This strategy was adopted so that temperature reconstructions might be achieved at both regional and very large spatial scales. The focus here is on the use of one growth parameter: maximum latewood density (MXD). The detailed nature of the temperature sensitivity of MXD across the whole network has been explored and the dominant common influence of mean April–September temperature on MXD variability is demonstrated. Different approaches to reconstructing past temperature for this season include the production of detailed year-by-year gridded maps and wider regional integrations in the form of subcontinental and quasi-hemispheric-scale histories of temperature variability spanning some six centuries.