Timber iQ August- September 2018 // Issue: 39 | Page 34

FEATURES
Timber can be treated via numerous methods as well as with various products available.
Continued from page 30
Breedt says fungi develops from minute spores that
germinate in suitable conditions and send out filaments
called hyphae. These penetrate the wood structure, and if
suitable conditions exist, break down the wood tissues into
simple chemical compounds on which they feed. Conditions
necessary for the development of fungi include moisture
content suitable for their development, adequate oxygen
supply, a temperature range to suit their life cycle, adequate
nutrients and sufficient time.
Most timbers, under certain conditions, may be attacked
by wood borers or beetles. Infestation by some wood borers
may be of little or no significance, whereas attack by other
borers may be serious and necessitate remedial or
preventative action. “Wood borers are beetles which at the
larval stage of their development bore into wood for food or
shelter and tunnel in the timber to derive their nourishment.
With some exceptions, the only damage they cause as adult
beetles is the cutting of a flight or emergence hole through
the surface of the timber as they escape from it. In South
Africa the wood borers of main concern can be categorised
as the Lyctid, Cerambycid and Anobiid species,”
highlights Breedt.
Conradie says virtually all non-durable timbers can be
attacked by wood boring insects of one sort or another that
may cause extensive damage to the timber. “The most
important wood borers are known as the powder-post
32 AUGUST / SEPTEMBER 2018 //
Beetle, the European house borer and the common furniture
beetle. Marine borers attack all non-durable timbers
exposed in sea water especially in the warm waters of
tropical zones.”
In the case of termites, or white ants, damage is accepted
as a significant risk to building and other structural timbers
in most parts of South Africa. “Wood destroying termites can
cause devastating damage to building and structural
timbers. Although drywood termites are mainly restricted to
the Durban area, subterranean termites are found virtually
throughout South Africa,” notes Conradie.
Wherever there is a risk of termite attack, it is wise to take
some precautions. For buildings, these precautions usually
take the form of chemically treated-soil barriers or physical
barriers and the use of properly preserved treated timber.
“There are many varieties of termites and borers
encountered in various localities and there appears no
reason to think that the areas affected are not spreading.
Like bees and some ants, termites are social insects living in
colonies which with some species, in a mature colony, may
contain large numbers of termites,” says Breedt.
In terms of physical degradation, ultra-violet (UV)
radiation present in sunlight has a strong degrading effect
on wood, particularly when combined with moisture
fluctuations. The periodic movement of moisture into and
out of the wood causes more serious breakdown of its
See more on page 34