Defects in timber can be caused by natural forces during tree growth, the seasoning and conversion processes, or biological attacks. Natural defects include knots, shakes, heart shakes, star shakes, cup shakes, radial shakes, pitch pockets, rind galls, and twisted fiber, which occur as the tree grows. Defects caused by seasoning and conversion after felling include bowing, cupping, springing, twisting, waney edges, case hardening, honeycombing, and stick staining. Biological attacks by fungi like dry rot and wet rot can cause decay if wood moisture levels are too high. Preventing fungal growth requires keeping wood dry, providing good ventilation, using well-seasoned lumber, and treating