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Natural Characteristics I

Effects of Growth Ring

  • Growth rings are distinctive due to the light and dark colors
  • Lighter portion is usually grown in the spring, called “springwood”
  • Darker portion is usually grown in the summer, called “summerwood”
  • Wide Growth RingWide Growth Ring
  • Narrow Growth RingNarrow Growth Ring

Burl Grain

  • Also known as curly grain, burly grain, fiddleback, or figure wood
  • Causes include knot location, damage to cambium layer of bark, and tree genetics
  • Common in most wood types
  • Burl Hard MapleHard Maple
  • Burl Red OakRed Oak
  • Burl Soft MapleSoft Maple

Tiger Stripe and Cross Fire

  • Unique pattern common in Red and White Oak
  • Also in Hard and Soft Maple
  • Most often found along with burl grain
  • Tiger Hard MapleHard Maple
  • Tiger Soft MapleSoft Maple

Bird’s Eye

  • Small area where fibers form circular figures on the surface
  • Common in Hard Maple
  • Rare in other wood types
  • Bird’s Eye Hard MapleBird’s Eye Hard Maple


  • Closed Knot. Flat face with no openings in the surface.
  • Open Knot. May occur as a very small pin-sized hole to a large gaping hole.
  • Unsound Knot. A portion of the wood will move readily. Also known as a loose knot.
  • Sound Knot. Also known as a tight knot. Solid, with no portion moveable. As hard as surrounding wood with no signs of decay.
  • Pin Knot. Small, sound, and tight.
  • Knot Cluster. A grouping of usually small knots.
  • Closed KnotClosed Knot
  • Open KnotOpen Knot
  • Unsound KnotUnsound Knot
  • Sound KnotSound Knot
  • Pin KnotPin Knot
  • Knot ClusterKnot Cluster

Bird Peck

  • Woodpecker produces a small hole, which is a starting point for brown to blackish mineral streak
  • Most common in Hickory and Cherry
  • Bird PeckBird Peck in Hickory

Cat’s Paw

  • Cluster of pin knots in the shape of a cat's paw
  • Most common in Cherry
  • Cat’s PawCat’s Paw in Cherry