The temperatures employed in kiln drying typically kill all

The temperatures employed in wood drying kilns typically kill all the fungi and insects in the wood if a maximum dry-bulb temperature of above 60 °C is used for the drying schedule. This is not guaranteed in air drying.
If air drying is done improperly (exposed to the sun), the rate of drying may be overly rapid in the dry summer months, causing cracking and splitting, and too slow during the cold winter months.
The significant advantages of conventional kiln drying include higher throughput and better control of the final moisture content. Conventional wood drying kiln and solar drying both enable wood to be dried to any moisture content regardless of weather conditions. For most large-scale drying operations solar and conventional kiln drying are more efficient than air drying.
Compartment-type kilns are most commonly used in timber companies. A compartment kiln is filled with a static batch of timber through which air is circulated. In these types of kiln, the timber remains stationary. The drying conditions are successively varied from time to time in such a way that the kilns provide control over the entire charge of timber being dried. This drying method is well suited to the needs of timber companies, which have to dry timbers of varied species and thickness, including refractory hardwoods that are more liable than other species to check and split.