Seasoning of wood

The process of removing moisture from freshly cut down trees is known as seasoning. 

In these trees the percentage of moisture is very high. The wood used for engineering purposes containing high percentage of moisture may cause many types of problems, such as shrinkage, distortion. To avoid this seasoning is done. After seasoning the percentage of moisture is reduced to 10-20% .

Advantages:
1. Durability and strength is increased.
2. Work ability is improved.
3. Fatigue of worker is reduced due to decrease in weight.
4. Distortion is minimized.
5. Surface finish is improved.
6. Resistance to fire is increased.
7. Ability for polishing and painting is improved.

NATURAL SEASONING

In this boards are stacked on to each other in shed. The boards are prevented from direct exposure of sun and rain. A platform is made about 50cm from the ground level and it is properly leveled. 

Some items such as ash or sand is sprayed on this layer for preventing from exposure of moisture and shed is fabricated on this platform. Then the sleepers are stacked in the shed keeping a gap between the sleepers for free circulation of air. Free circulation is allowed around the wood. The position of sleepers should be changed periodically which will increase the rate of drying. 
Due to this, the excess of moisture gets evaporated very easily and the sleepers becomes dry. By this method best seasoning wood is available at cheaper rate. 
Time required for seasoning also depends upon the type of wood to be seasoned i.e. hard wood takes more time as compared to soft wood. It is kept for 6 months to 2 years.

KILN SEASONING

In this method the wooden pieces are kept on huge trolleys and then it is placed inside the hot chamber of a furnace known as kiln. In this way wooden pieces are kept in a controlled atmospheric conditions for two weeks. The time depends upon the type of wood and initial moisture content. Blowers are also used. It is a quick drying method and the moisture is reduced to 10%. Since seasoning is done at a lesser time through artificial means so the quality of wood is inferior in comparison to seasoned wood through natural seasoning.

WATER SEASONING

In this method the wooden pieces are immersed in flowing water for about one month. During this period the flowing water removes the excess of sap in the wood. 

Then the wooden pieces are taken  for complete seasoning is lesser but by this method strength of wood gets reduced after seasoning. Sap is reduced from the wood. It is done by water itself. After it air seasoning is done.