Quality of Good Timber Wood

Describe the quality of a good timber (wood).

A wood for carpentry and joinery should have the following qualities. It should,

(i) be free from stained sap wood.

(ii) be free from defects like knot, twisted, fibers, heart shake, cup and ring shake.

(iii) be properly seasoned to suit the specific use. It’ should have no defect like radial shake, twisting and bowing, case-hardening and honey combing etc.

(iv) be free from any defect caused by insects.

(v) be sound, bright and free from any discoloration.

(vi) have regular annual rinks and should not clog the saw teeth during the sawing operation.

Describe the classification of trees.

Trees are generally classified into two groups.

1. Exogenous Trees

2. Endogenous Trees

1. Exogenous Trees

These trees grows outwards and their concentric rings (called annual or annular rings) are distinct. Each ring represents one year growth. These are further divided into two types.

(a) Conifers or evergreens

(b) Deciduous or broad-leaf trees

The conifers are evergreen trees and are classed as soft wood. The trees under this type are Deodar, Kail, Chir, Pine, Walnut and Fir. The deciduous or broad-leaf trees are classed as Hard Woods. This type of trees are Sal, Teak, Shisham, Oak, Beach and Ash. Hard woods are used mostly in engineering works.

(ii) Endogenous Trees

These trees grow end-ward by depositing each fresh layer internally instead of doing so on the exterior. Palm, cane and bamboo come under this category. Growth of a tree takes place by the formation of cells during the growing season.