Dendrochronology and the study of crannogs.

The dendrochronological potential of wood from two crannogs was
evaluated. Consisting predominantly of non-oak species with fewer than
50 year-rings, the assemblages required the development of new
techniques and approaches.
The problem of validating cross-matches between short ring sequences
was resolved by a new methodology based on internal consistency. A
group of internally consistent sequences contains no conflicting
chronological relationships in the full set of its pairwise
correlations. The SORT.STRING program, designed to identify sets of
internally consistent groups in large data-sets, was tested on two
'known' data-sets. It successfully identified the correct chronological
relationships in these data-sets. Applied to the assemblages from the
crannogs, it identified small, mutually exclusive groups of sequences
which could not be satisfactorily merged to form a site chronology.
Reasons for this are explored and indications for future work
identified.
The dendrochronological potential of alder (Alnus glutinosa)was
examined and a suitable methodology developed. Cross-correlation and
chronology formation are possible but extreme ring-width values, i.e
signature years, and compression of the outermost rings re identified
as problematic features.
Evidence for woodland management practices in the crannog assemblages
was evaluated. A model for woodland management was formulated, on the
basis of two samples of modern coppiced material. This distinguishes
between adventitious and formal coppice. Application of the model to
hurdles found on the Irish crannog indicates that they are the products
of adventituous coppice.