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Natural Characteristics II

Pitch Pocket

  • Insects cause injury to the bark, leading to formation of gum spots in the wood
  • Common in Cherry
  • Pitch PocketPitch 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 TrackWorm 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 HoleWorm 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 RotIncipient 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 FleckingNarrow Rays in Red Oak
  • Wide RaysWide Rays in Red Oak


  • Outer portion of bark is the non-living portion which protects the inner living portion
  • BarkBark on outer edge

Bark Pocket

  • Bark-filled hole on the board surface
  • Bark PocketBark 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
  • Mineral Streak
  • Mineral Streak