How does the seasoning of timber help?
A. It increases the weight of timber
B. It improves the strength properties of timber
Try it first: pick an option, then read the explanation.
The Purpose of Seasoning
Seasoning is the process of reducing the moisture content of freshly felled timber (green timber) to a level suitable for its intended use. Green timber can have a moisture content of 100-200%, meaning the water in the wood weighs more than the wood fibre itself. This excess water makes the wood heavy, weak, and unstable. Seasoning removes this water, leading to significant changes in the timber's properties.
Detailed Analysis of the Statements
Statement A: It increases the weight of timber
This statement is incorrect. The primary goal of seasoning is to remove water. Since water has significant weight, removing it from the timber makes the wood substantially lighter. A seasoned piece of timber is much lighter than an unseasoned piece of the same size.
Statement B: It improves the strength properties of timber
This statement is correct. As water is removed from the wood's cell walls (below the Fibre Saturation Point), the wood fibres become more compact and rigid. This leads to a significant improvement in most of its mechanical properties, including hardness, stiffness, and compressive and bending strength. Seasoned timber is considerably stronger than green timber.
Effects of Seasoning on Timber Properties
| Property | Effect of Seasoning | Reason |
|---|---|---|
| Weight | Decreases significantly | Removal of water. |
| Strength & Hardness | Increases significantly | Wood fibres become more compact and rigid. |
| Dimensional Stability | Increases (less shrinkage/warping) | Moisture content is stabilized. |
| Durability | Increases (resistance to rot) | Moisture is too low for fungi to thrive. |
Study Tips
- Seasoning = Drying: Always remember that seasoning is fundamentally a drying process.
- Drying makes things lighter: Think of a wet towel versus a dry one. The dry one is always lighter. The same applies to wood.
- Drying makes wood stronger: As wood dries, its fibres stiffen and bond more strongly, improving all its mechanical properties.