Conversion and Market Forms of Timber Wood

Explain the conversion and market forms of Timber (wood).

Conversion and Market Forms of Timber Wood

Falling of a tree should be done in summer (middle) or mid winter, because during these periods the sap is at rest. When the growth of a tree is full it becomes ready for falling. Trees should be felled as near to ground as possible. The process of sawing wood into different forms in which it is available in the market is termed Conversion. This is done before a wood is seasoned.

The conversion of wood is accomplished by several methods of cutting a log according to its use for different purposes. However, the following three methods of sawing are quite common.

(a) Flat, Slab or Ordinary Sawing

This is carried out by cutting a log into various parallel saw cuts and is one of the simplest methods of conversion. But the process is somewhat defective because the boards or planks thus sawn usually warp.

(b) Tangential Sawing

This method is adopted when a timber has distinct annual rings and ill-defined medullar rays. The boards sawn by this process have their face tangential to the annual rings. Such boards are seasoned quickly. The wastage in conversion is also less.

(c) Quarter or Radial Sawing

In this method the long is first sawn into four pieces (Quartered) and each quarter is so sawn that the boards width remain along the medullar rays. The rays appearance is irregular on the surface. The method is an expensive one and there is considerable wastage of wood during processing. Timber thus sawn finds its application mostly in cabinet or other decorative work.

Conversion of Wood is done in the Following Form

(i) Log Is only a trunk without the branches.

(ii) Balk is rough squared log.

(iii) Posts are squared pieces of timber having width 175 to 300mm or round pieces of 175 to 300mm in diameter.

(iv) Deals are 225mm wide and about 100mm thick parallel side pieces.

(v) Planks are parallel sided pieces having 50 to 100mm thickness, 275-300mm width and 3-7metres length.

(vi) Board or Battens are 25 to 50mm thick and 125 to 175mm wide pieces.