Why is wood seasoning done

When the drying is done in a kiln, the product is known as kiln-dried timber or lumber, whereas air drying is the more traditional method. Seasoning is the process of removing the moisture content from wood to minimize structural problems when used in construction or to provide less smoke and more uniform combustion when used as firewood.

There are two main ways of seasoning timber, Natural Air and Artificial Kiln drying. Both methods require the timber be stacked and separated to allow the full circulation flow of air, etc. Air seasoning is the method used with the timber stacked in the open air.

The process of removal of moisture content from wood, so as to make it useful for construction and other uses, is called drying of wood or seasoning of wood.

Seasoning of Timber is a process by which moisture content in a freshly cut tree is reduced to a suitable level. By doing so the durability of timber is increased. Natural Seasoning is the most traditional way of seasoning wood or timber. In this method wood is dried usually by the keeping the wood exposed to air, so that the moisture evaporates and wood is seasoned. Kiln drying of lumber is perhaps the most effective and economical method available.

Drying rates in a kiln can be carefully controlled and defect losses reduced to a minimum. Length of drying time is also greatly reduced and is predictable so that dry lumber inventories can often be reduced. Where staining is a problem, kiln drying is often the only reasonable method that can be used unless chemical dips are employed Chemical seasoning of wood.

Precautions During Seasoning of Timber During air seasoning, seasoned timber should be protected from high humidity and rain exposure. For easy and uniform passing of air and water s a suitable gap between logs should be kept. Disadvantages of Natural Seasoning of Timber: This process is long and depends on natural air. In natural seasoning, the ends of timber dry fast and split. Interior portion of wood may remain moist while exterior part dries quickly.

During the natural seasoning, there is a possibility of fungal and insect attack. Reduction of moisture using salt solution is called chemical seasoning. After the absorption of water by the solution logs are let to dry. It increases the strength of the timber. There are many ways of seasoning or drying timber, but only two methods have been found satisfactory, principally for economic reasons. They are air drying and kiln drying.

Air drying will be considered in detail in this publication, but kiln drying is a special- ized process. Denser hardwoods such as hickory, birch, oak, beech and maple not only burn hotter but also longer. If more heat and longer burn times are desired, go with hardwoods. On the other side, spruce, pine, willow, cottonwood, cedar and other softer woods will burn faster and not generate as much heat. To identify well-seasoned wood, check the ends of the logs. If they are dark in colour and cracked, they are dry.

Dry seasoned wood is lighter in weight than wet wood and makes a hollow sound when hitting two pieces together. If there is any green colour visible or bark is hard to peel, the log is not yet dry. After seasoning has been done timber is not liable to be decayed. After seasoning, the timber becomes dry , hard , light in weight , less in bulk and resilient. It is the best method of seasoning. In this method, water or moisture is driven out from the timber by a very slow process of evaporation.

The object of seasoning is to ensure regular and uniform drying all throughout the timber. In this method logs are kept immersed in ponds or in running streams with the root ends upstream for three to four weeks.

Maximum sap is washed out by this process. The logs should be kept entirely down under water by chaining them. Now after that, these logs are kept under the shed for free air circulation.

This is to be the best method of artificial seasoning, as it has no adverse effect on the appearance and strength of the timber. The time required varies with the nature of timber, usually 15 days to two months. Timber seasoned by this method is rendered hardened, denser and proof against dry rot. But it is a costly method of seasoning timber. In this method, timbers are stacked with one third air space in a chamber.

Therefore timbers are exposed to a moist warm atmosphere.