BRIDGE REPAIR/REHABILITATION FEASIBILITY STUDY

COMMERCIAL TIMBERS OF THE CARIBBEAN
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TABLE 8.— Classification of Caribbean timbers as to their resistance to marine borers
Trade name
Scientific name
Trade name
Scientific name
1 Rating based on published reputation or rating of
closely related species rather than research results.
under Permeability. Wherever possible, reference
is made to the ease with which a timber
absorbs preservatives under both open-tank (nonpressure)
and pressure treatments. The absence
of a section on permeability in the timber descriptions
indicates that reliable information is not
available.
Heartwood ordinarily resists preservative treatment
more than sapwood, although the sapwood
of some timbers is also extremely resistant to preservatives.
And when a sapwood resists preservatives,
the wood is virtually eliminated from
use where decay is a problem, for sapwood is
always more susceptible to decay than heartwood.
On the other hand, posts and poles with wide easily
impregnated sapwood can give good service
2 Resistance varies according to location. Recent tests
indicate this timber is not highly resistant in many areas.
after thorough treatment, even though the heartwood
may be only moderately resistant to decay.
Preservatives are applied by either pressure
or nonpressure methods. The various nonpressure
processes include the following : (1) Superficial
application of preservatives to the wood
with brushes or a spray nozzle or by a brief dipping;
(2) soaking in preservative oils or steeping
in water solutions; (3) diffusion process using
waterborne preservatives; (4) various adaptations
of the hot-and-cold-bath process; (5) vacuum
treatment; and (6) a number of other miscellaneous
nonpressure processes. The superficial application
of preservatives with brushes or by momentary
dips is used to some extent in the Caribbean
area and, with an oilborne preservative, may add