Effect of Steaming and Kiln Drying on the Properties of Southern Pine Poles. Part II: Chemical Properties

Investigations of the relationship between strength reductions due to steam conditioning of southern pine poles and changes in chemical composition indicate that the reductions in strength that were noted are due to chemical degradation of the wood substance. Chemical analyses of steamed specimens revealed a highly significant relationship between toughness and changes in the carbohydrate fraction of the wood. Although steam conditioning adversely affects the mechanical properties of southern pine poles, the beneficial effect of steaming on permeability must be considered in judging its value in the treating process. Specimens for this study were obtained from one tree of loblolly pine and of willow oak. Sixty specimens of each species were assigned to each of six treatment groups for steaming for various periods up to 20 hours. The specimens were tested for toughness following ASTM Standard 17143-52. Changes in toughness, bolo-cellulose, alpha cellulose, hemi cellulose, and lignin with steaming are tabulated.

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