How Termites Damage Wood: A Scientific Approach

Termites are small insects known for their ability to digest wood and other cellulose-containing materials. They pose a serious threat to wooden structures and furniture, especially in tropical and subtropical areas. This article scientifically discusses how termites attack wood, the biology of termites, and why certain types of wood are resistant to termites.

Biology of Termites

Types of Termites

There are several types of termites, but the most common ones that damage wood are:

1. Subterranean Termites: These termites live in the ground and build tunnels to reach wood.
2. Drywood Termites: These termites live directly in the wood and do not need contact with the ground.
3. Dampwood Termites: These termites live in moist or decaying wood.

Feeding Behavior

Termites feed on cellulose, a complex carbohydrate found in wood, paper, and other plant materials. They break down cellulose into simple sugars that they can digest. This process occurs thanks to symbiotic microorganisms in their intestines, such as protozoa and bacteria, which assist in the breakdown of cellulose.

Mechanism of Wood Damage

1. Exploration and Infestation

• Pheromones: Termites use pheromones to lead each other to food sources. Worker termites explore the environment in search of wood.
• Tunnels and Galleries: Subterranean termites build muddy tunnels to reach wood. Drywood termites bore directly into the wood and create galleries.

2. Cellulose Breakdown

• Symbiosis with Microorganisms: Termites can digest cellulose thanks to microorganisms in their intestines. These microorganisms break down cellulose into glucose, which termites use as an energy source.
• Enzymatic Breakdown: Termites also produce enzymes, such as cellulase, that aid in the breakdown of cellulose.

3. Damage Pattern

• Internal Damage: Termites eat wood from the inside out, making the structure hollow and weak without clear external signs of damage.
• Galleries and Chambers: Within the wood, termites create extensive networks of galleries and chambers where they live and reproduce.

Why Some Types of Wood are Resistant

1. Natural Oils and Extractives

• Toxic Substances: Many resistant wood types contain natural oils, resins, or extractives that are toxic to termites. These substances can kill or repel termites.
• Examples: Teak contains tectol and tectonaquinone, substances that repel termites. Red Cedar contains thujaplicins, natural oils with insect-repellent properties.

2. High Density and Hardness

• Physical Barrier: Wood types with high density and hardness are harder for termites to penetrate. This complicates their ability to tunnel and digest the wood.
• Examples: Cumaru and massaranduba have very high densities, making them physically resistant to termites.

3. Resins and Tannins

• Chemical Defense: Some wood types contain tannins and resins that have fungicidal and insecticidal properties. These substances can disrupt the digestion of wood by termites.
• Examples: Oak contains high concentrations of tannins that repel both fungi and insects.

Experimental Research and Observations

Scientific research on the resistance of wood to termites often involves controlled experiments in which different wood types are exposed to termites. These studies measure the extent of damage, termite mortality, and the effectiveness of the natural defense substances in the wood.

• Laboratory Studies: In laboratory conditions, wood blocks of different species are incubated with termites to test resistance. Parameters such as weight loss of the wood, termite mortality, and tunneling behavior are measured.
• Field Studies: In natural environments, wood samples are exposed to termites to evaluate their durability in real-world conditions.

Conclusion

Termites attack wood by exploring, infesting, breaking down cellulose, and ultimately causing extensive damage. Wood types that are resistant to termites often have natural oils, high density, and chemical defense substances that repel or kill termites. Understanding how termites attack wood and which wood types offer natural resistance can help make informed choices for wood use in termite-prone areas. By using resistant wood, we can significantly extend the durability and lifespan of wooden constructions.