Structure and chemical properties of fresh and degraded wood: their effects on radiocarbon activity measurements

Abstract

The complexity of the chemical makeup of wood is such that it is very difficult to define the inter-relationship of the various major components. This thesis has endeavoured to outline inconsistencies found by various researchers with respect to C-14 activity measurements on whole wood and chemical fractions of wood. Wood chemistry literature has been surveyed extensively in an attempt to clarify the relationship between the major components of wood from different tree species. Many pretreatment techniques used to isolate an uncontaminated chemical wood fraction for C-14 activity measurements have been described in the literature. Several of these techniques have been studied with respect to both fresh and degraded wood in order to compare their efficiency in isolating a viable chemical fraction which is free of any possible contaminating components. It has been concluded that, because of the variability in chemical makeup of wood from different tree species, the only reliable chemical fraction is pure cellulose. The problem of solvent retention in wood after extraction processes has been examined using C-14 labelled solvents, and a method minimizing solvent retention has been proposed. The structure of a series of fossil wood samples has been examined using techniques such as X-ray diffraction spectrometry, and it has been found that the degree of structural degradation can be measured. The results are inconclusive with regard to the categorization of possible degradation mechanisms, but they indicate that the possibility exists that some categorization may be obtained from a more detailed study. Show more