Dendro dating

This is because the number of rings in the sapwood varies widely, with some estimates suggesting that the range may be from 15 to 50 rings in the sapwood of mature oak trees in 95 per cent of the cases considered in the UK.In Kent, 18 samples of oak taken from different medieval timbers indicated a smaller range of 15 to 35 sapwood rings.

By comparing variations in the first 100 years growth (ie the innermost 100 rings) with those of the last 100 years growth (ie the outermost 100 rings) of similar timber felled locally 100 years ago, the match should be immediately apparent.

If the older timber retains its bark, the year that it was felled will be recorded by the outermost ring, the ring which was grown in the year that the tree was felled.

All the samples are then cross-checked with each other to identify any possible measurement errors and abnormalities before a master curve is prepared based on average tree ring sequences.

and a co-founder of Cathedral Communications Limited.

Tree rings: each ring represents one year's growth.