The radial splits which are wider on the outside of the log and narrower towards the pith are known as:- 

The radial splits which are wider on the outside of the log and narrower towards the pith are known as:-  Correct Answer Star shakes

Concept:

Various forms of defects in timber due to Abnormal growth or rupture of tissues due to natural forces are as follows:

Checks: It is a longitudinal crack that is usually normal to the annual rings. These adversely affect the durability of timber because they readily admit moisture and air.

Shakes: These are longitudinal separations in the wood between the annual rings. These lengthwise separations reduce the allowable shear strength without much effect on compressive and tensile values. The separations make the wood undesirable when appearance is important.

Different types of shakes:

Star Shake: 

• These are radial splits or cracks wide at the circumference and diminishing towards the center of the tree.
• This defect may arise from severe frost and the fierce heat of the sun.
• Star shakes appear as the wood dries below the fiber saturation point.
• It is a serious fault leading to a separated log when sawn.

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Heart Shake: 

• These occur due to shrinkage of heartwood when the tree is overmatured.
• Cracks start from the pith and run towards sapwood.
• These are wider at the center and diminish outwards.

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Cup Shake 

• These appear as a curved split that partly or wholly separates annual rings from one another.
• It is caused due to excessive frost action on the sap present in the tree, especially when the tree is young.

Rind gall: 

• It is characterized by swelling caused by the growth of layers of sapwood over wounds after the branch has been cut off in an irregular manner.
• The newly developed layers do not unite properly with the old rot, thereby leaving cavities, from where decay starts.