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 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 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 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 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

• Narrow Rays in Red Oak
• Wide Rays in Red Oak

Bark

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

• Bark on outer edge

Bark Pocket

• Bark-filled hole on the board surface

• 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

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