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 As poles age, external decay may develop as the effectiveness of the treatment begins to decline.
External decay in the above ground sapwood zone frequently occurs in red cedar poles in which
only the butts have been treated. This type of decay is called shell rot.
7.1.1.2 Insects. Attacks of the untreated interior portions of poles by subter-
ranean termites or carpenter ants are difficult to detect. However, if insects can gain entry, so can
decay fungi. Therefore, the two will often occur together.
7.1.2 Inspection Procedures. The purpose of pole inspection is to: (a) identify poles
which are dangerous and should be replaced, (b) identify poles which are in the early stages of
deterioration so that corrective action can be taken, and (c) establish/maintain the installation's pole
plant records.
7.1.2.1 Visual. A visual examination of the poles, using binoculars to inspect
tops, can provide valuable information regarding the pole's condition.
Decay. Machined, damaged areas, and checks should be critically examined
during visual inspections. The size and location of seasoning checks should be noted. In general, the
wider the check, the deeper it penetrates and the more likely untreated heartwood is exposed.
Remember, only decay in the advanced stages is readily apparent. The presence of fungi in wood
where decay has not progressed appreciably can be detected only by culturing or microscopic ex-
amination of the wood. Incipient decay can extend four feet or more above internal rotten areas in
Douglas-fir poles.
Surface decay usually occurs at or below the ground line, so digging is generally necessary to detect
it. It can also occur above ground in the sapwood of untreated cedar poles.
Termites and Carpenter Ants. These insects infest the internal untreated
portion of poles. Therefore, little external visual evidence of their presence is apparent. Some ter-
mite galleries may be present if the insects are trying to bridge over treated wood. In addition, if a
carpenter ant infestation has occurred, scattered bits of very fibrous and sawdust-like frass may be
present in the area. Since a break in the protective shell must occur before these insects can reach
and infest the untreated wood, decay is also likely to be present.
Vertebrate Organisms. Damage from vertebrate organisms, such as
woodpeckers, is usually apparent. Binoculars should be used when inspecting large poles. If the
damage is fresh, broken pieces of wood from the excavated hole should be present on the ground.
Decay will be associated with older damage (Figure 7-3).
Mechanical. Mechanical damage is generally obvious and found in the
ground line area to a few feet above the ground.
7-4
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