Influences of Basic Chemical Research on Western Red Cedar Utilization

The build-up of a fund of knowledge of the chemical extractives of western redcedar (Thuja plicata Donn) covering the steam-volatile oil components and the water soluble polyphenols is described. The relationship of these extractives to the solution of the utilization problems of decay variability, pulping corrosion, metal staining, and paint bleed-through is presented showing that background research on the basic chemistry of a species can contribute very substantially to complete utilization of a previously underutilized species. The most important contribution of background research has been the determination of two types of corrosion in kraft pulping — vapor-space corrosion traceable to the thujaplicins and liquor-space corrosion traceable to the pyrocatechol-containing lignans. It was demonstrated that certain stainless steels would perform adequately in the presence of these compounds. Research on the thujaplicin content of young trees has indicated that no decay-preventing extractives are synthesized in the juvenile heartwood. This research has shown the necessity for trimming shingles to eliminate the chocolate-brown material near the pith. Research on extractive bleed-through on painted cedar, has shown that the use of vapor barriers and oil-base alkyd primers can control this problem. Future developments include possible use of the petroleum-ether solubles of western redcedar for insect control, and research involving clarification of the process of sapwood-heartwood transformation.

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