Durability

Another important quality required for timber is it should to be durable. It should have a long life. It should be capable of resisting the actions of fungi, insects, chemicals, physical agencies and mechanical agencies during its lifespan.

Elasticity

This is the property of a material which returns to its original shape when the load causing the deformation is removed. Timber should possess this property, as it is essential when timber is used for bows, carriage shafts, etc.

Structure

It should possess a uniform structure. This is ensured when there is firm adhesion of fibres and compact medullary rays. Further, the annual rings should be regular and closely located.

Fire-resistant

As timber is a bad conductor of heat, it should be dense enough so that it resists fire. A good timber should not contain resins and other inflammable oils since they accelerate the action of fire.

Hardness

The timber should be hard so that it is in a position to offer resistance when it is being penetrated by another body. As such hardness is imparted to the wood by chemicals present in the heartwood and the density of wood.

Strength

The timber should be strong enough to effectively act as structural members, such as joists, beams, rafters, etc. Further, it should be in a position to sustain loads applied gradually or suddenly to it. Preferably, the strength should be adequate in direct and transverse directions.

Classification of Other Woods

Sal, another hardwood, grown in the sub-Himalayan regions and in Madhya Pradesh, is heavier than teak, which has to meet the requirements of first-class deodar. Timbers of Mango, Benteak, etc., are categorized as second-class.