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Wood Characteristics - Natural Characteristics II

Pitch Pocket

  • Insects cause injury to the bark, leading to formation of gum spots in the wood
  • Common in Cherry

Pitch Pocket

Pitch Pocket
in Cherry

Worm Track

  • Also called pith fleck
  • Small, narrow, yellowish to brownish streaks 1/32” to 1/16” wide and
  • 1/8" to 2" long
  • Caused by insects, whose burrows are filled in by new cell growth

Worm Track

Worm Track

Worm Hole

  • Caused by worms
  • Tunnel size ranges from 1/64” to 3/16”
  • Wood moisture content must be above 30% for oak timberworms to continue activity

Worm Hole

Worm Hole in
Red Oak

Incipient Rot

  • Also known as decay, is the decomposition of wood by fungi. Incipient rot is rot in the early stages
  • Slight discoloration or bleaching of wood
  • Wood moisture content must be above 30% for rot-causing fungi to grow

Incipient Rot

Incipient Rot in
Red Oak

Ray Flecking

  • Stripes of cells that extend radially
  • Rays store food and transport it horizontally
  • Most common in Red Oak and White Oak
  • Visible in hardwood types that are quartersawn and have rays
  • Examples show ray flecking with variations in ray width

Ray Flecking

Narrow Rays in
Red Oak

Wide Rays

Wide Rays in
Red Oak

Bark

  • Outer portion of bark is the non-living portion which protects the inner living portion

Bark

Bark on
Outer Edge

Bark Pocket

  • Bark-filled hole on the board surface

Bark Pocket

Bark Pocket

Mineral Streak

  • Darkened or discolored wood area
  • Blackish-blue, well-defined streak running parallel with grain
  • Caused by minerals which the tree extracts from the soil
  • May also be called mineral stain
  • Common in Maple and Birch, occasionally in Oak and Cherry

Mineral Streak

Narrow Rays in
Mineral Streak

Mineral Streak

Wide Rays in
Mineral Streak

Mineral Streak

Wide Rays in
Mineral Streak