PRESERVATION OF ROUNDWOOD POLES BY THE SAP REPLACEMENT METHOD WITHOUT PRESSURE APPLICATION

Abstract

A number of preliminary trials with poles of Eucalyptus saligna helped to establish an appropriate sap replacement treatment process. Factors studied included solution strength, bark removal influence, pole length limitations, tolerable pre-treatment delay and preservative retention uniformity. Treatment success was assumed achieved if the pole absorbed a pre-determined quantity of preservative. Relating to the treatment by the full-cell pressure method, treatability responses of poles belonging to eight wood species commonly grown in Kenya plantations were compared. As preservative retention built up towards the pole absorption end, the treatment gave poor results compared with the full-cell process. Retention was also largely confined to the outer sapwood. Despite these drawbacks and the additional risk of exposure of the untreated wood by splitting on drying, the method has scope in preservation of certain classes of wood products, such as fence posts and building poles.