Dieases + Defects

Question 1

How is a knot formed

Answer 1

A knot forms when a branch meets the trench of a tree. All knots reduce the strength of the timber.

Question 2

What is a resin pocket

Answer 2

The grain in softwood often contain open chambers that contain resin. When these chambers are cut into, the exposed resin leaks out. This weakens the wood.

Question 3

How are shakes formed

Answer 3

Shakes are caused by tension forces that build up in the tree while it grows or dries.

Question 4

Give 3 examples of a shake

Answer 4

1. Heart shake
2. Star shake
3. Cup shake

Question 5

How does case hardening occur

Answer 5

If boards season too quickly, the outer surfaces dry, leaving the centre less dry. The resulting stress leads to case hardening.

Question 6

How do stains and discolouration occur

Answer 6

By chemicals, weathering, fungi

Question 7

How does wet rot occur

Answer 7

Wet rot affects timber that is exposed to the elements or is wet. The affected wood becomes moist and slimy as it rots while a white residue often forms

Question 8

How does dry rot occur

Answer 8

When fungus attacks the wood, eating the cellulose in the wood.