1. Defects in timber
Defects are blemishes in timber that reduce the quality and utility value of timber.

2. Defects in timber Defects in timber are categorized into two:
Natural defects
Artificial defects

3. NATURAL Defects in timber
This occurs during the growth of the tree. Common examples are:
Star shakes
Heart shakes
Cup or ring shakes
Rind galls
Knot
Upset grain
Cross grain

4. NATURAL Defects in timber
STAR SHAKES
These are radial splits which are wider on the surface and narrower as they move towards the centre.

5. NATURAL Defects in timber
HEART SHAKES
These are wide splits running right through the heart of a tree

6. NATURAL Defects in timber
CUP OR RING SHAKES
These are curved splits , separating one annual ring from the adjacent one either wholly or partly.

7. NATURAL Defects in timber
RIND GALLS
These are peculiar swelling or abnormal growth caused generally by the growth of layers of sapwood over wounds remaining after a branch of tree has been imperfectly cut off.

8. NATURAL Defects in timber
KNOT
They occur at the point where branch grow from the trunk of a tree. It at times rot away and fall out of position leaving what is called knot-hole

9. NATURAL Defects in timber
UPSET GRAIN
This occurs during growth or felling due to knocks it receives.

10. NATURAL Defects in timber
CROSS GRAIN
This occurs when the wood fibre does not align parallel to the axis of the piece of wood.

11. ARTIFICIAL Defects in timber
DRY ROT
This occurs as a result of fungi attack on the timber, thereby reducing the timber to a dry powder.

12. ARTIFICIAL Defects in timber
WET ROT
This is the decay of timber due to alternate wetting and drying

13. ARTIFICIAL Defects in timber
CUP
This is the concave curvature across the surface of the timber, resulting from bad stacking and shrinkage during drying.

14. ARTIFICIAL Defects in timber
BOW
This is either concave or convex curvature along the length of the plank.

15. ARTIFICIAL Defects in timber
CHECK
This is the separation of wood along the grain of the board.

16. ARTIFICIAL Defects in timber
TWIST
This is a spiral form of distortion along the length of the plank.

17. ARTIFICIAL Defects in timber
INSECT ATTACK.
Insects attack woods by boring on its surface. These holes render wood unsuitable for project.

18. ARTIFICIAL Defects in timber
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