Dendro dating wood
These occurrences make the determination of growth rings and dendrochronological work with diffuse-porous species more difficult than with ring-porous species such as oak.
The biological regularity of the ring series in trees from temperate zones permits dating of wood by comparing the ring sequences of undated wood with those of wood of known age and position in time.
• For the cross dating of curves, a minimum number of rings must be present in order to obtain reliable results.
Unfortunately, it is not possible to list a precise number as the required minimum.
However, in all cases it is necessary to clean the edges of the panel for a full recognition of the rings.
The purpose of cross dating is to find out if and to what degree the two sequences match.
Dendrochronology focuses on the annual periodicity of growth which is controlled by the climate, e.g. In cool and temperate climates, there is a dormant season from autumn to spring and a growth season during the summer.
On the other hand, the records regarding the number of sapwood rings to be added are derived from statistical evaluation and must be considered in each particular case.
Even curves considered quite ‘long’ sometimes do not provide the necessary characteristic patterns which would help to date the curve.
There are many variables involved; sometimes dating is possible with as few as fifty tree rings, but sometimes even one hundred rings may not be enough. Sapwood estimation and seasoning Identification of the year the tree was felled is the most important information the art historian can learn from the dendrochronologist.
In order to determine the ring widths one can use a magnifying glass with an integrated scale.
This method is used if measurements have to be taken on site without laboratory equipment.