Short Answer:

Good quality timber should be strong, durable, and free from defects like cracks or knots. It must have uniform color, be easy to work with, and not break or bend easily. Timber should also resist pests, moisture, and weather to ensure long-lasting performance in construction.

Other important properties include a pleasant smell, smooth texture, and the ability to hold nails or screws firmly. Good timber does not shrink, swell, or twist much and provides both strength and beauty in furniture, doors, windows, and structural works.

Detailed Explanation:

Properties of good quality timber

Timber is widely used in construction, furniture making, and carpentry because of its natural strength, workability, and appearance. However, not all wood is suitable for building purposes. For timber to be considered good quality, it must possess certain physical and mechanical properties that make it durable, strong, and easy to use in different environmental conditions.

Here are the key properties of good quality timber:

1. Strength:
   One of the most important properties of good timber is its strength. It should be able to bear heavy loads without bending, breaking, or cracking. Strong timber is used in beams, roofs, door frames, and structural parts of buildings. The strength depends on the type of tree, age, and treatment of the wood.
2. Durability:
   Good quality timber must resist attacks from insects, fungi, and termites. It should also be able to withstand weather effects like rain, sunlight, and wind. Durable timber does not decay or rot easily and lasts for many years when used in construction.
3. Toughness and Elasticity:
   Timber should be tough so that it does not break easily under impact or shocks. Elasticity means the timber should return to its original shape when the load is removed. This is important in places where the wood is used for supporting moving loads or pressure.
4. Workability:
   Timber should be easy to cut, shape, and join with tools. It should allow smooth nailing, sawing, and finishing without breaking. Wood that is too hard or too soft may not be suitable for general construction work.
5. Appearance:
   Good timber has a uniform color, straight grains, and a pleasant smell. It should have a smooth texture and not contain defects like large knots, splits, or cracks. Appearance is especially important for decorative works and furniture.
6. Resistance to Moisture:
   A good quality timber should not absorb water quickly. It should resist shrinking or swelling due to moisture changes. If the timber swells too much in damp conditions or shrinks too much in dry air, it may crack or become loose in joints.
7. Fire Resistance:
   Though wood is flammable, some types of good quality timber are slow to catch fire or burn slowly. This is helpful in reducing fire damage and improving building safety.
8. Seasoning and Stability:
   Good timber is well-seasoned, which means it has been properly dried to remove extra moisture. Seasoned timber is more stable and does not warp, bend, or split over time. It also becomes lighter and stronger.
9. Nail and Screw Holding Capacity:
   Timber should be able to hold nails and screws tightly. If the wood is too soft or has internal cracks, nails may loosen and reduce the strength of the joints.
10. Free from Defects:
    Good timber is free from visible defects like knots, shakes, twists, insect holes, or fungal spots. These defects reduce the strength and appearance of the timber and may lead to failure in use.

Conclusion:

Good quality timber is strong, durable, tough, easy to work with, and resistant to decay, pests, and moisture. It should have a uniform appearance, hold fasteners well, and maintain its shape and strength over time. Using such timber in construction ensures safety, durability, and good finish in all types of wooden works.