Wood Defects Flashcards
- natural wood defect
- these are in effect the basal stamps of incipient or cast-off branches in the living tree
Knots
- natural wood defect; type of knot
- small knots 1/2 “ (12.5mm) or under often caused by the shedding of early branches
Pin knots
- natural wood defect
- knots sliced through their length during sawing
- “slash knots”
Spike or Splay knots
- natural wood defect; type of knot
- dead knots which are still sound and difficult to dislodge
Encased knots
- natural wood defect; type of knot
- two or three knots springing from a common center
Branched knots
- natural wood defect
- built-in tensions are created which tend to level out either in the growing tree under certain adverse conditions resulting to extensive splitting in the weakest links
Shakes / “splits”
- natural wood defect; type of shake
- log splits from the pith or heart radially along the medullary rays
- one shake is a “heart shake” while two is a “double heart shake”, several is a “star shake”
Radial shakes
- natural wood defect; type of shake
- project inwardly; from outside
- result of severe weather
Frost shakes
- natural wood defect; type of shake
- “ring shake”; shakes are with the rings of the tree
Tangential shakes
- natural wood defect; type of shake
- when log is opened, there are spots in the middle body of the trunk
Cross shakes
- natural wood defect
- “resin pockets”; can appear either as thin veins or shallow cavities filled with resin
- usually caused by damage to the cambium layer in resinous wood
Pitch Pockets/ Pitch Veins
- natural wood defect
- damage to the cambium layer by small insects; may show as small dots or patches of brown cork deeply buried in some woods
Pitch Flecks
- natural wood defect
- patches of ingrowing bark caused by exterior damage to a growing tree
- ex: nailing into a tree
Rind Galls
- natural wood defect
- the wood usually separates and breaks away along the ring during conversion
Internal Sapwood
- natural wood defect
- can be used either by fungal or insect attack, irritating the cambium layers, resulting in large lipid growths forming a dense mass
- may enhance the value of timber
Burls / Burrs
- natural wood defect
- tissue formed over a wound in a tree resulting in unnatural growth
Callus
- natural wood defect
- caused by fungoid disease; dead sections of bark
Canker
- natural wood defect
- partially heated fire scar; depression on the surface of the log where the tree failed to recover from the injury
Catface
if the structure of wood is unequal or lacking in elasticity, and incorrect seasoning various forms of distortion, splitting, will occur.
Artificial defect
- artificial wood defect
- hollows across the width, forming a rounding on the under face
- often due to incorrect piling
Cupping or Rounding
- artificial wood defect
- plank is curved like a bow throughout its length
Bow or Bowing
- artificial wood defects
- edge bend; wood remains flat but bends edgewise
Sprining / “crook”
- artificial wood defect
- diagonals are curved; “in-winding”
Twisting
- artificial wood defect
- terms for distortion in one or more directions
Warping or Casting
- artificial wood defect
- butt ends of the plank splits open, caused by too rapid drying
- happens after cutting the wood
End Splitting
- artificial wood defect
- wood surface is covered with small splits along the grain caused by too rapid drying in hot sun
Sun Checking
- artificial wood defect
- the result that the dry outer layers are in tension, and the moist interior compression
Case Hardening
- artificial wood defect
- surface of the wood lifts in small layers caused by the cutting action, structural weakness, or incorrect seasoning
Flaking
- artificial wood defect
- grain runs obliquely to the longitudinal axis due to incorrect sawing
Diagonal grain
- artificial wood defect
- resulting in severe internal stresses and subsequent checking or disruption of the wood fibers, not visible from outside
Honeycombing
- artificial wood defect
- characterized by extensive shrinking and warping
Collapse
thin layer entirely surrounding the trunk that is in active growth
Cambium layer
