Effect of Moisture Content and Preservatives on the Discoloration of Oil Palm (Elaeis guineensis Jacq.) Lumber

Abstract

Considering the current rate of expansion of the lumber processing industry in the world, the current annual allowable cut of one million cubic meters of round logs is considered to be insufficient to satisfy the increasing demand of timber industries. One major area that has been highlighted in the forest policy is the introduction of lesser-used species to widen the natural resource base of the forest and to address the imbalance between supply and demand for the resources. As a contribution to addressing this problem, oil palm lumber, a lesser-used species, was subjected to different moisture content variations to determine its behavior with respect to discoloration. Specimens of oil palm trunks were extracted at Norpalm Oil Mill in the Western Region of Ghana. Oil palm lumber specimens were conditioned in a kiln to a moisture content of 15%, 20%, 25%, 30%, 40%, and 50%. The results obtained covered discoloration and mold. The effect of the extractives on the discoloration of oil palm lumber was also investigated by means of immersing some samples of oil palm lumber into sea water and tap water for 48 h. Although Dursban 4E is a widely used preservative in the timber industry, oil palm lumber specimens of 40 mm thick immersed in Dursban 4E for 48 h and conditioned in a kiln to a moisture content of 30% were discolored from week 2. However, oil palm lumber specimens of 40 mm thick that were immersed in tap water for 48 h, and thereafter immersed in Dursban 4E for another 48 h, then kiln dried to a moisture content of 15%, 20%, 25%, and 30%, did not show any discoloration from week 2 to week 18. It was discovered that in the utilization of oil palm lumber, it should be immersed in tap water for 48 h before any chemical treatment is given, and thereafter kiln dried. From the general results, the species proved to be good substitute for some of the ‘noble’ species that are going extinct from the forests of Ghana.