Decay. Machine-damaged areas and checks should be critically ex-
amined during visual inspection. 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. Remem-
ber, 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 examination of the wood.
Early decay can extend four feet or more above internal, visibly rotten
areas in Douglas-fir poles. Surface decay usually occurs within the first
12 to 18 inches below the ground line, so digging is generally necessary to
detect it. Periodic application of groundline preservative treatments will
prevent and/or control this type of decay.
Termites and Carpenter Ants. These insects infest the internal untreated
portion of poles. Therefore, little external visual evidence of their
presence is apparent. Some termite galleries may be present if the in-
sects 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 wood-
peckers, is usually apparent. Binoculars should be used when inspecting
large poles. If the damage is fresh, broken pieces of wood from the ex-
cavated hole should be present on the ground. Decay will be associated
with older damage.
Vertebrate control may require permits from the Federal government or
state. Recommendations and assistance for control should be obtained
from the cognizant EFD [Appendix (A)].
Mechanical. Mechanical damage is generally obvious and found in the
ground line area to a few feet above the ground.
Physical Tests. In addition to visual inspection, several physical tests are
available to aid pole inspectors in determining the presence of biological
damage. Some of these methods are very basic while others involve
sophisticated electronic equipment. In all cases, considerable experience
is required to interpret the results, especially with the newest non-
destructive testing devices for wood poles.