Question

Which of the following species is classified as heavy woods?

• A. Dalbergia sissoo
• B. Anogeissus latifolia
• C. Shorea robusta
• D. Tectona grandis

Hint:

Sal (Shorea robusta) is highly resistant to decay and termite attack due to the high concentration of natural resins in its heartwood.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Timber species are classified into weight categories based on their density or specific gravity at a standard moisture content of \(12\%\).

Step 2: Detailed Explanation:
1. Woods are classified based on specific gravity:
- Light woods: Specific gravity \(< 0.50\)
- Moderately heavy woods: Specific gravity \(0.50\text{--}0.70\)
- Heavy woods: Specific gravity \(0.70\text{--}0.85\)
- Extremely heavy woods: Specific gravity \(> 0.85\)
2. Shorea robusta (Sal) has an average air-dry density of approximately \(800\text{--}850\ \text{kg/m}^3\), corresponding to a specific gravity of \(0.80\text{--}0.85\).
Therefore, it is classically categorized as a heavy wood of high strength and durability, widely utilized for railway sleepers and heavy structural construction.
3. While Anogeissus latifolia is also heavy, Shorea robusta is the standard benchmark timber species classified in this category in Indian wood technology.

Step 3: Final Answer:
The species classified as heavy wood is Shorea robusta.