give and explain three defect due to abnormal grawth
Assuming this is about timber/wood, three defects caused by abnormal growth are:
Knots — a branch is enclosed by the growing trunk. The grain bends around it, creating a hard or weak spot. Knots can loosen, cause splitting, and make the wood harder to work.
Reaction wood — formed when a tree leans or is bent by wind. Softwoods form compression wood and hardwoods form tension wood. It has different density and shrinkage, so it warps, cracks, and machines unevenly.
Shakes — internal cracks or splits along the grain caused by growth stresses or injury. They weaken the timber and allow moisture and fungi to enter.
Key principle: abnormal growth displaces fibers, changes density, or builds up internal stress. That is why these defects reduce the wood’s strength, stability, or workability. Rind gall and burls are also acceptable examples.
