Holz Roh Werkst (2004) 62:303–306 DOI 10.1007/s00107-003-0460-z ORIGINALARBEITEN · ORIGINALS L. Edwin · A. G. Gopalakrishna Pillai Resistance of preservative treated rubber wood (Hevea brasiliensis) to marine borers Published online: 19 June 2004  Springer-Verlag 2004 Abstract The susceptibility of rubber (Hevea brasilien- sis) wood to marine borer attack limits its use for marine purposes. In the present study three types of biocides viz. copper creosote, arsenical creosote and a dual preserva- tive treatment with copper- chrome- arsenic and creosote were selected for comparing their relative efficacy in preventing biodeterioration. The treated panels were ex- posed at the test site in Cochin harbour. The extent of internal damage through marine borer attack was assessed through visual observations, X-ray photographs and me- chanical strength testing. The untreated test panels were destroyed within six months whereas it was found that preservative treatment prevented biodeterioration under marine conditions. This was confirmed by radiographic studies and comparison of compressive stress at maxi- mum force. The service life of this cheaply and easily available timber can be increased to meet the growing demand of timber in the small-scale fisheries sector. Resistenz von behandeltem Gummibaumholz gegen Bohrmuscheln Zusammenfassung Die Anfälligkeit von Gummibaum- holz gegen den Angriff von Bohrmuscheln begrenzt seine Verwendung für die Seefahrt. In dieser Studie werden drei Typen von Bioziden ausgewählt, nämlich Kupfer-Kreo- sot, Arsen-Kreosot und eine zweifache Schutzbehandlung mit Kupfer-Chrom-Arsen und Kreosot. Die entsprechen- den Schutzwirkungen gegen biologischen Abbau wurden ermittelt und verglichen. Die behandelten Platten wurden im Hafen von Conchin zur Prüfung ausgesetzt. Das Aus- maß der Schädigung durch Bohrmuscheln wurde visuell, mittels Röntgenaufnahmen sowie durch Prüfen der me- chanischen Festigkeit bestimmt. Die unbehandelten Pro- ben waren innerhalb von sechs Monaten zerstört, während die Schutzbehandlung den biologischen Abbau im Meer verhinderte. Das wurde bestätigt durch radiographische Untersuchungen und Drucktests bei maximaler Last. Die Lebensdauer dieses billigen und leicht erhältlichen Schnitt- holzes kann soweit erhöht werden, dass die Anforderun- gen des kleinen Wirtschaftssektors der Fischerei erfüllt werden. 1 Introduction India has a land area of 329 million hectares. Of this a forest cover of 110 hectares (33%) is stipulated by the National Forest Policy of 1952 for the maintenance of ecological stability. The actual forest cover available now is only 19%. The high demand of timber can be met by the utilization of less used species, social forestry prod- ucts and wastes from commercial plantations. The most readily available of these species is the rubber wood (Hevea brasiliensis). Commercial plantation of rubber started in Kerala, India in the year 1905. The Rubber Board estimates the availability of rubber wood in India as 1.25 million m 3 per year. It is estimated that 0.62 million m 3 /yr can be made available to meet the re- quirement, 45% of the rubber wood is consumed for the manufacture of packing cases. The veneer industry ac- counts for 11% of the consumption and the rest goes as firewood in the brick industry (Mannothra 1993). The density of the wood ranges from 435–626 kg/m 3 . It is a moderately refractory timber and is easy to treat (Anon 1993). The mechanical properties such as modulus of rupture and compressive stress parallel to grain are comparable with that of conventionally grown timbers (Shukla and Lal 1985). The other mechanical properties also compare well with other timbers (Gnanaharan and Damodharan 1992). The highly perishable nature of the wood and its susceptibility to warping while seasoning makes it unsuitable for common use. The biodeterioration of this timber can be prevented by suitable preservative treatment through which this wood can be utilized to re- lieve the pressure of the Indian forests. Preservation and protection of rubber wood against biodeterioration has been studied (Goh et al. 1983, Hong L. Edwin ( ) ) · A. G. G. Pillai Central Institute of Fisheries Technology, Cochin 682029, India e-mail: root@cift.ker.nic.in