BCM: Wood

Below are reasons why wood continues to be an

important construction material, except.

• availability

• fire resistance

• relatively low cost

• ease of use

• durability

Select THREE (3) characteristics of good timber.

• Narrow annual rings,

  closer the rings, greater is

  the strength.

• No woolliness at fresh cut

  surface.

• When struck sonorous sound

  is produced.

• Variable texture.

• Light weight

Defects in lumber may effect wood's appearance and mechanical properties.

Below are causes of defect in lumber, accept?

• natural growth

  of wood

• wood

  diseases

• change in

  weather

• rapid

  seasoning

• animal

  parasite

What is the type of lumber that cause by mishandling or seasoning

What is the type of lumber that cause the absent of material at the edge or bark

What is the type of lumber that cause due to

error during cutting or heavy winds.

What is the type of lumber that cause by

branch bases that incorporate into the tree trunk.

Below are correct statement about FUNGI, accept.

• Fungi may exist due to availability of food, proper range of temperature, moisture, & oxygen

• Fungi can be avoided by proper handling in storage placement

• Fungi growth in conducive temperature between 10°C to 40°C

• FSP that suitable for fungi's' growth are more than 30%

Below are correct statement about INSECTS, accept.

• Proper seasoning can prevent wood-attacking insects

• Termites enter structures through wood that is close to the ground

• Application of sealing compounds layering onto wood surface may prohibit entry of insects

• Poorly ventilated or wet environment leads to existence of termites in wood structures

• Beetles and termites are the most common wood-attacking insects

Below are correct statement about BACTERIA, accept.

• Rapid storage of wood that have contact with soils leads to bacteria growth

• Bacteria cause wet wood where the water-soaked condition occupies the stem centers of living trees.

• Bacteria cause the softening of wood skin due to excessive shrinkages during re-dried process

• Black heartwood causing by bacteria at the stem center that turn dark brown or black in color.