การใช้ไม้จากต้นยางพารา

บทคัดย่อ

ABSTRACT

Annual cut of old stock Para-rubber trees on replacing scheme of Thailand is around 6 million Cu.M. . The scheme will be run continuously for 30 years at a rate of 60,000 Ha.per year. Para-rubber wood is traditionally used for fuelwood and charcoal making, some clear bole trunk partially used for Furniture making, Furniture component, Flooring, Moulding, Blockboard, Fibreboard, particleboard and Wood Cement Board. Because of its white colour and fine texture, the para-rubber wood is especially good for Furniture and Furniture Component making for export.

At an age of 25 years old most of para-rubber tree will be cut for replanting, at that age the old tree will reach 30 cm. DBH., and 10 metres of the trunk lenght is usable, the trunk usually burred and tapered caused by tapping scar. The wood has distinct annual ring which making good pattern when tagential sawn, Colour of the wood will be white right after fresh cut and turn to yellow when dried. Thin board of Para-rubber wood is usually end-splitted and bended caused by the wood stress. Sawing of Para-rubber wood should keep far from pitch for prevention on split and bending of the sawn timber. Piling of Para-rubber wood board should dividen by 1 inch stickers they will take around 55-60 days of seasoning in open air.

Fresh cut Para-rubber wood will consist about 40 % of moisture content and the wood is also rich in starch caused the wood easily attacked by fungi within 1-2 days after felling. The attacking of fungi will first start on both cut-ends and then move to the area near the pitch. Blue stain is a normal discolouration defect of the wood spoiling the quallity of the products, the problem can be solved by using wax mix with 2 % of Captafol rubbing on the surface and ends of the wood, the prevention can last 2 weeks long and after that wood preservatives are reccommened. The Blue stain occured on para-rubber wood-chip can be assumed as a natural fermentation of sugar in the wood and become one of the way to dissolve the wood's sugar content by nature, the discoloured wood-chip can be used as raw material for Wood Cement Board making.

Latex left in Para-rubber wood will make an inaccuracy in sawing short lenght conversion should be considered for reducing of bending and cracking. 10 % of Permathrin with 5 minutes dipping is recommended as a solution for preventing of fungi and insect attack. CCA (Copper-chrome-Asenate) is also reccommended for treating the wood.