Timber is susceptible to attack by insects and fungi at any stage of processing.
From the moment a tree is felled in the forest, wood-borers such as ambrosia beetles can penetrate the wood, taking with them fungal spores which cause further damage and loss in value through discoloration and staining. Thereafter at the sawmill or in its final form, wood is still open to attack. Unless treated with a suitable preservative, serious structural damage to buildings can occur through infestation by dry-wood borers or woodrots. The risk to timbers is even more acute now that environmental pressures are resulting in more restricted use of scarce hardwoods in the constructions and furniture industries. Softwoods are more susceptible to attack by insects and fungi, increasing the need for use of effective timber preservatives.