Dendroclimatology is the science of extracting past climate information from information in trees. Initial work focussed on measuring the tree ring width - this is simple to measure and can be related to climate parameters. But the annual growth of the tree leaves other traces, and in particular maximum latewood density is generally found to be a better proxy for temperature than ring width. It is, however, harder to measure.

Tree ring information can be used, with caution, to reconstruct climatology at the growing site for certain seasons back thousands of years. For more recent times, the established connection between tree rings and climate appears to be breaking down. Briffa et al report in Nature, 1998:

During the second half of the twentieth century, the decadal-scale trends in wood density and summer temperatures have increasingly diverged as wood density has progressively fallen. The cause of this increasing insensitivity of wood density to temperature changes is not known... [1].

See also

• Dendrochronology
• temperature record of the past 1000 years
• proxy