Bird Peck
Bird peck is shown here in hickory, but is also common
in maple. Woodpeckers produce a small hole, which is the
starting point for brown to blackish mineral streak. |
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| Bird Peck |
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Cats Paw
Wood characteristic that has the shape of a cats paw caused
by pin knots. Also is most common in cherry. |
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| Cats Paw |
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Pitch Pocket
Pitch pocket (sometimes referred to as gum spot) is common
in cherry. It is caused mainly by peach bark beetles and
cambium miners. The feeding insects cause injury to the
living portion of the bark, leading to the formation of
gum spots in the wood as the tree continues to grow. |
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| Pitch Pocket |
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Worm Track
Worm track (also referred to as pith fleck) is shown here
in hickory. Worm track appears as small, narrow, yellowish
to brownish streaks 1/32" to 1/16" wide and
1/8" to 2" long. Worm track is caused by cambium
miners feeding beneath the bark from the branches to the
roots. Their tiny burrows are filled in by new cell growth
and become embedded in the wood as the tree continues
to grow. |
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| Worm Track |
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Worm Hole
The damage in this red oak example was caused by oak timberworms.
These worms cause most worm hole damage seen in red and
white oak. The worm tunnel size ranges from 1/64"
to 3/16". Wood moisture content must be above 30
percent for timber worms to continue activity. |
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| Worm Hole |
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Incipient Rot
Rot (also known as decay) is the decomposition of a substance
by fungi. This photo of red oak shows incipient rot, which
is rot in the early stages, and is identified by a slight
discoloration or bleaching of the wood. Rot-causing fungi
grow only in wood with a moisture content above approximately
30 percent and cease growing when the wood is dried below
30 percent. |
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| Incipient Rot |
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Ray Flecking
Ray flecking is visible in hardwood species that are quartersawn
and have rays. Rays are stripes of cells that extend radially
within a tree. These rays primarily store food and transport
it horizontally. Red oak and white oak are most noted
for this characteristic. The examples show ray flecking
with variations in ray widths. |
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| Wide Rays in Red Oak |
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| Narrow Rays in Red Oak |
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Bark
This example shows a piece of lumber with bark on its
outer edge. The outer portion of the bark is the non-living
portion which protects the inner living portion from external
damage. |
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| Bark |
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Bark Pocket
This example shows a typical bark pocket with a bark-filled
hole on the board surface. |
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| Bark Pocket |
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