Pengaruh Konsentrasi Bahan Pengawet Boron terhadap Retensi dan Penetrasi pada Kayu Rakyat

Abstract

INTRODUCTION. Nowadays, wood supply from natural forest continues to decrease. It resulted in the development of community forest in many areas in Indonesia. In general, community forest has been developing using fast-growing species. The wood obtained is generally inferior compared to that from the natural forest, particularly in term of natural durability and strength. Therefore, it is necessary to improve the quality of such kind of woods. The aims of the research were to determine the natural durability of wood species from community forest and to evaluate effect of boron concentration onto retention and penetration of these species. Wood natural durability was evaluated after exposing the samples in the field for 3 months following the procedure of American Standard for Testing and Material (ASTM) D 1756 2008. MATERIALS AND METHOD. The main materials used were the wood of durian (Durio zibethinus), karet (Hevea brasiliensis), manii (Maesopsis eminii) and petai (Parkia speciosa) from small business unit of sawmill in Cinangneng, Bogor. The others are boron with three concentrations (5%, 10% and 15%) as the preservative, and curcuma extract, alcohol, chloric acid (HCl), aquades and salicylic acid as dying solution. Preservation process applied was cold bath method for 2 hours. Retention and penetration were used as the indicator. Data was then analyzed using experimental design factorial randomly by two factors (wood species and boron concentration) with three replications. RESULT AND DISCUSSIONS. The result showed that natural durability of all wood species studied was low. It belongs to Durability Class of IV and V. This indicates that all wood species need to be enhanced through the preservation. Based on this study it showed that petai wood has the highest value of the retention (4.31 kg/m3), while durian wood was the lowest (2.37 kg/m3). Retention value of karet wood, known is rubberwood, was almost similar to that of manii wood. Result also showed that penetration value of all wood species studied were almost similar namely 50.13% (durian), 51.55% (karet), 51.57% (petai) and 52.78% (manii). The results indicate that retention value was influenced by wood species, boron concentration and the interaction of these two factors, while penetration value was only affected by the concentration. Factors of wood species which affect the retention are related to the anatomical structure, as well as the existence and the amount of free hydroxyl group (-OH-) that are present in the cell wall components. In general, retention and penetration values tend to increase with the increasing of boron concentration. In all wood species studied, the concentration of 15% resulted in the highest of retention and the deepest of penetration.