Certain wood species are naturally resistant to
termite attack and offer an alternative to preservative-treated wood. It is
important to note, however, that it is only the heartwood (and sometimes the
bark) that exhibits termite resistant properties. Thus, in the brief
descriptions below, it is only the heartwood that is being considered.
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| Relevant articles |
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Redwood (Sequoia sempervirens)
This
wood species has been known to possess some natural resistance to decay and
termite feeding. Our research with redwood indicates a fairly high
durability in short-term exposures to high termite activity. Findings also
suggest that extractives from this wood are quite toxic to Formosan
subterranean termites. |
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Alaska cedar; Pacific Coast yellow cedar
(Chamaecyparis
nootkatensis)
Termite bioassays with Alaska cedar have shown this
wood to be slightly more durable than redwood. Short-term exposure to high
termite activity also resulted in slightly higher termite mortality than
redwood. The same study also revealed that given a choice, subterranean
termites actually preferred Alaska cedar less than redwood. Alaska cedar
can be considered to be a reasonable construction material substitute for
redwood in terms of its resistance to subterranean termites. |
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Laotian teak (Tectona grandis)
Teak shows considerable resistance to subterranean termite attack. Its
resilience in field tests have resulted in it being compared to lumber
treated with ACZA and CCA. Perhaps the greatest drawback in teak is its
relatively high cost, which is likely to limit its use in construction. It
is currently unknown how resistant teak is to drywood termites. |
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Sugi (Cryptomeria japonica)
Commonly
used for construction in Japan, this wood has a high resistance to
subterranean termite attack. Along with tallowwood and milo, sugi holds
much potential as a Hawaii-grown wood species for cultivation and
utilization in termite-resistant wood products. |
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Kou (Cordia subcordata)
Along
with kamani, kou possesses substantial natural resistance to feeding by
subterranean termites. In the past, Hawaiians commonly used it to make
tableware. This species is now somewhat rare, however, making future use
of this species for construction doubtful. |
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Kamani (Calophyllum inophyllum)
Kamani
is a wood species with considerable natural resistance to termite attack.
Although it is occasionally used for construction in some parts of the
world, it suffers from substantial shrinkage during drying and can be
difficult to work with. |
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Milo (Thespesia populnea)
Milo
is a fairly dense wood with a relatively high resistance to shrinking,
lending itself to cabinet and boat construction in some parts of the
world. In Hawaii, it is commonly used for fashioning crafts and bowls.
This wood may have some potential as a Hawaii-grown termite-resistant
species. |
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Tallowwood (Eucalyptus microcorys)
This
wood is used extensively for construction in Australia, and exhibits
fairly significant resistance to subterranean termite feeding. One
of the slower growing species of the Eucalyptus genus, E.
microcorys shows potential for use as a plantation species here in
Hawaii. |
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Casuarina pine (Casuarina
equisetifolia)
The casuarina pine is one of several
termite-resistant trees of interest to the Hawaiian forestry industry. It
is found both in Hawaii and Malaysia and has been shown to be very
resistant to subterranean termite feeding. Findings from laboratory
studies indicate that extractives in this wood may be somewhat toxic to
termites. |
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Kempas (Koompassia malaccensis)
The Malaysian kempas tree showed considerable termite resistance and high
termite toxicity in a recent laboratory study. However, these results
contrast somewhat from field studies conducted in Malaysia, where Koompassia
spp. suffered significantly greater degrees of termite damage. |
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Tualang (Koompassia excelsa)
Another Malaysian tree, tualang has been shown in a recent laboratory study
to be somewhat toxic to Formosan subterranean termites. The same study
also showed this wood species to be quite resistant to termite feeding. |
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Sentang
(Azadirachta excelsa)
Sentang (the Malaysian name for this
tree), a relative to the neem tree, is not necessarily the most resistant
wood to termite attack. However, a recent laboratory study has shown it to
be quite toxic to Formosan subterranean termites. Although it may not have
the same construction potential of some of the other naturally resistant
woods, it does hold potential for use as a plantation wood. |
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