Timber durability: Which timber species offers the highest natural resistance against white ants (termites)?
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AChir (pine)
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BShisham (Dalbergia sissoo)
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CSal (Shorea robusta)
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DTeak (Tectona grandis)
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EDeodar (Cedrus deodara)
Answer
Correct Answer: Teak (Tectona grandis)
Explanation
Introduction / Context:Natural durability of timber influences maintenance cycles, chemical treatment needs, and lifecycle cost. Resistance to biological agents like termites is especially important in warm, humid climates and in ground-contact applications.
Given Data / Assumptions:
- Comparison is among commonly used Indian subcontinent timbers.
- “Maximum resistance” refers to untreated, natural durability.
- Service conditions are typical building works, not marine borers or extreme exposures.
Concept / Approach:Teak possesses natural oils and extractives that deter termites and decay, giving it a superior durability class. Sal and shisham are durable and strong but generally considered less termite-resistant than teak in many references. Chir (a softwood) is more susceptible unless treated.
Step-by-Step Solution:List species and typical durability rankings.Identify teak’s natural oils/extractives → excellent termite resistance.Compare others: sal and shisham are durable but usually not as termite-resistant as teak; chir is comparatively poor.Choose teak as the most resistant.
Verification / Alternative check:Field performance and standards frequently list teak in higher durability classes with proven termite resistance.
Why Other Options Are Wrong:Chir: softwood with lower natural durability.Sal/Shisham: strong and durable but typically below teak’s termite resistance.Deodar: aromatic but not typically superior to teak for termite resistance.
Common Pitfalls:Assuming strength equals termite resistance; durability depends on extractives and anatomy, not just density.
Final Answer:Teak (Tectona grandis)