Applying multi-parameter dating to Scottish historical buildings

The dendroarchaeological dating of wooden structures of importance to cultural heritage has made use of several physical and chemical properties of tree-rings as dating parameters. However, no study has yet made use of earlywood blue intensity (EWBI) despite the fact that this parameter can be generated inexpensively and at the same time as ring width (RW) and latewood blue intensity (LWBI) data. In this study, we have made use of all three of these tree-ring parameters in a multi-parameter approach to the dating of eleven previously dated historical pine structures across Scotland using an R-code script called MultiXdateR. This was undertaken with the aim of validating the code and the multi-parameter approach to dendroarchaeological dating and also to assess whether there is any scope in using EWBI in future dating studies. Our results demonstrate that a multi-parameter approach to dating is not only successful but is actually advantageous over more traditionally used methodologies since it makes use of a parameter combination (COMBO) approach obtained by averaging the sliding correlation time-series of the other three parameters. This allows for spurious correlations to be minimised while maximising the ‘true’ peak correlation at the correct temporal location. We have also demonstrated that EWBI, although not quite as consistent as LWBI in suggesting a date for the outer ring of a historical timber sample, is generally more reliable than RW and thus there is good scope for its inclusion in future multi-parameter dendroarchaeological studies. Finally, we have provided preliminary evidence of the stability of the climate signal captured by EWBI as a function of elevation, which may prove useful in future studies dating timbers with an original low-elevation provenance.