Endless supply of valuable material

Press, 28 August 1980, Page 21

Endless supply of valuable material

Forests provide one of man’s most valuable materials — wood. They can do this endlessly if they are managed wisely. Supplies of wood need not run out as in time must those of oil, coal, iron, and other metals. Moreover, forests can be used for other purposes, such as tramping and hunting, while producing wood. Indeed, the provision of roads, bridges and other facilities needed to collect wood from a forest often allows hunters, fishermen and trampers to reach their favourite areas more easily. People now depend on wood for many purposes. First, it can be used much as it comes from the forest for pos’s on farms or telegraph poles, though in this' form it has usually to be treated with chemicals that wil l prevent the wood from rotting. Next, wood, as logs from the forest, can be sawn into pieces of various sizes and used directly for building, furniture, and similar purposes. Again, wood can be used in its natural state, cut into large thin sheets which are glued together to form plywood, which is light but very strong. Beams and large arches for big buildings can be made similarly by gluing together sawn boards —• this is called lamination.

Another way of using wood is to chip it into small pieces an form these with glue into sheets of various thicknesses called particleboard. In its manufacture, much of what would otherwise be waste can be used. Wood can also be broken down into its smallest particles, called wood fibres, by grinding U,, up or by cooking it wit j chemicals that dissolv, the material holding th I fibres together. : The fibres are former | into pulps, from which I several types of papers" (including that used for newspapers), cardboarci and building boards (soft-i board and hardboard) ar< I made by various pro-1 cesses. Large amounts of woo< i were once needed to coo meals, heat homes, an< even to fuel steal engines. Firewood is now seldoi used for anything bu open house fires, thoug substantial quantities c charcoal are being pre duced from wood for bar becue cooking. Wood can also b broken-down into a rang of products by a proces. 1 not yet established in Ne\ Zealand, known as wooi distillation. However, Nei Zealand industry doemake turpentine and othe products in .the course o converting wood int< pulp(information supplier by New Zealand Fores Sendee).