Utilization of coconut timber from north Sulawesi, Indonesia. Part 2: Treatability
Under tropical conditions coconut wood is quickly degraded by mold and blue stain fungi. Low density wood in ground contact is commonly decomposed by wood destroying fungi within a period of only a few months, higher density wood from the outer stem regions within 24 to 30 months (MOSTEIRO, CASIN, SERIBAN 1976; McQUIRE 1975). Moreover, according to McQUIRE (1975) green wood of lower density is highly susceptible to ambrosia beetles (Ambrosia sp.). For these reasons freshly sawn wood must be treated immediately, preferably by pressure treatment. Impregnation by a vacuum-pressure process of dry coconut wood with water-soluble CCA preservative had been carried out repeatedly and results published by PALOMAR (1979), JENSEN (1979), and SULC (1976). If, however, green coconut wood could be successfully pressure-treated immediately after sawing the time-consuming and costly intermediate dip treatment would become obsolete. Yet, previous trials by PALOMAR (1979) with traditional vacuum-pressure techniques were little successful as preservative retention, decreasing disproportionately with moisture content, proved ineffective at high moisture levels. On the other hand, an oscillating pressure process for impregnating green softwood has also proven effective with impregnating tropical hardwoods such as Rubberwood (Hevea brasiliensis). There are as yet no reports in literature about the application to coconut wood of this treating process. Equally, little research has been dedicated so far to distribution and mode of fixation of chromium-based preservatives in monocots (WILLEITNER, CHEN 1985; WILLEITNER, BRANDT 1985; PEEK, WILLEITNER, BRANDT 1987). Hence, testing of the oscillating vacuum/pressure treatment with coconut wood was the objective of an investigations carried out partly at FRIM, Malaysia, and partly at the Federal Research Centre for Forestry and Forest Products (BFH), Hamburg, FRG.