Answer: A. pruning old trees
Timber is a valuable source of wood. It is of high economic value. Large number of wood are cut to meet the needs of the wood. Pruning is a practice of selective removal of certain parts of the trees like branches, buds and roots. It is a method of timber renewal. The old trees with dead wood can be used for obtaining timber by pruning of dead branches prone with diseases, this will improve the quality of the wood, which can be used as a source of timber.