Studies on soluble nutrient components in wood and their influence on decay susceptibility and preservative efficacy.
The work described in this thesis was undertaken to determine the nature and identity of soluble carbohydrate and nitrogenous components which migrate and accumulate at evaporative surfaces of dried wood and the influence these nutrients have on wood decay and preservative performance. Specific soluble carbohydrates and amino acids were shown to redistribute and accumulate at surface regions of wood during drying. Analysis of dried wood showed that soluble carbohydrates constituted 2-5% of the dry mass of wood at surface regions, and that soluble nitrogenous components constituted < 0.5% in the same areas. The soluble sugars which redistributed and accumulated at surface regions during drying were mainly reducing in nature in the softwoods. Glucose and fructose were the predominant sugars in these woods. In lime, sucrose was the predominant sugar. Soluble amino acids contributed to a significant proportion of the nitrogen content at surface regions of softwoods. In pine and spruce soluble amino acids constituted 30% and 40% of the total nitrogen content, but in lime, concentrations of soluble amino acids constituted only 6% of the total nitrogren content. The major amino acids observed in pine, spruce and lime were aspartic acid, glutamine and arginine. Soil burial studies undertaken highlighted the problems encountered when trying to mimic natural wood of high nutrient status. Test blocks impregnated with soluble sugars and amino acids displayed loss of these added nutrients on emplacement in soil, and the effect of added substrates could not be evaluated individually. The results of soil burial studies using CCA treated wood which was also impregnated with amino acids, showed that the latter influenced wood decay and preservative stability in lime. Weight losses in preserved lime were shown to correlate with increasing arginine and glutamine concentrations. A substantial copper loss was recorded in hardwoods and softwoods treated at sub-toxic levels with CCA and also treated with glutamine. Soluble sugars incorporated into preserved wood did not influence wood decay or preservative efficacy.