Examination of cellulose-lignin relationships within coniferous growth zones

• Main Author: Squire, Gordon Balfour
• Language: English
• Published: University of British Columbia 2011
• Subjects: Conifers; Wood > Chemistry; Cellulose; Lignin
• Online Access: http://hdl.handle.net/2429/35815

Lack of a selective holocellulose isolation procedure and the problem of limited material have long frustrated the attempts of wood scientists to accurately measure and describe carbohydrate yields within coniferous growth zones. A new method has been devised for micro-cellulose determination, Alpha-(formula omitted) cellulose yield maybe quantitatively estimated as the corrected yield of nitrated wood meal. Three - O.1 g wood meal samples provide a statistically reliable determination. A major limitation of the new technique, however, is that it cannot be applied to all woods. Sixty positions within ten increments representing five Canadian coniferous woods of different genera were examined and intra-incremental patterns were constructed. Anova and Duncan's test showed latewood (formula omitted) -cellulose yield to be greater than that of earlywood by a highly significant degree. Alpha-cellulose content throughout mature growth zones was estimated reliably by linear correlation or, more accurately, by logarithmic transformation used in a recent mathematical model. The successful application of the latter is its first reported use describing the non-linear behaviour of a wood chemical property across a coniferous increment. These patterns showed relationship of the long-chain carbohydrate fraction to seasonal development within coniferous growth zones. In addition, six of the ten patterns demonstrated new chemical evidence pertaining to a physiologically significant phenomenon in earlywood. Therein, minimum (formula omitted) -cellulose yield occurs at considerable cellular depth following cambial reactivation in the growing season. First-formed earlywood appears to retain some similarity at the chemical level of organization to last-formed tissues of the preceding season. Later-formed earlywood (i. e. , from the present year) does not appear to retain such similarity. From earlier work of this laboratory, lignification patterns were described for the same materials, using ultraviolet measurements on acetyl bromide-acetic acid digestion products of two wood meal samples. Examination of (formula omitted) -cellulose and lignification patterns provided evidence for their mutually exclusive behaviour. For the ten increments studied, the (formula omitted) -cellulose estimate (x̅ = 45.9 + 2.0%) was the exact complement of lignification (x̅ = 27. 4±1. 9%) at all positions but one. The linear regression for data from all increments was highly significant ( r = - 0.785). In addition, micro (formula omitted) -cellulose and micro lignin values, when combined, showed a definite tendency to cluster about a central value (x̅ = 73. 4 ± 1. 2%) suggesting that certain species require a common, critical measure of high molecular weight material. Dispersion about combined lignin and (formula omitted) -cellulose estimates was significantly less than about either of their individual means. This suggests much closer physiological control over the combination of these chemical entities, indicating that tree physiology is oriented more towards the finished bio synthetic product than towards the individual components involved in such a system. As a means of measuring successful nitrocellulose preparation, intrinsic viscosity (formula omitted) was used to indicate presence or absence of extensive degradation. Because of the highly variable at each position tested, no consistent trends in chain length were found across growth zones. However, in four increments, significant differences in (formula omitted) throughout the earlywood provided further evidence of two earlywood types. === Forestry, Faculty of === Graduate