The most common commercial
species of Grey Ironbark is Eucalyptus paniculata,
which is distributed from the far south coast of NSW
to north of Coffs Harbour. Another species also
referred to as Grey Ironbark is E. siderophloia. It
is distributed from southern coastal NSW to Maryborough
Ironbarks are a very characteristic group of trees, so named on account of
the thick, compact, hard bark. The name however could equally apply to the
timber itself, for it is certainly the ironwood of the whole Eucalyptus
genus. The wood is very heavy, hard and compact, making working with the
timber difficult. It ishard to nail and planes with
difficulty. Microscopically, the fibres are seen to
be very thick walled, compact and closely compressed.
The commercially available Ironbark species in NSW can be broadly divided
into Grey and Red Ironbarks.
The heartwood of the Grey Ironbarks ranges from light grey or light chocolate
with some darker reds and browns sometimes occurring. Sapwood is slightly lighter
in colour. Grey Ironbark may have various regional
variations such as the ‘Black Ironbarks’ around Port Macquarie, which have
similar light colours with black narrow to broad
streaks running through the timber. Texture is moderately coarse and even.
The timber is very hard to work, limiting some applications requiring fine
detailing. The heartwood is highly durable (Class 1), allowing a wide range
of external applications. The sapwood is not susceptible to Lyctid attack. Applications include heavy engineering,
marine structures, poles, boat building, framework, flooring and decking. It
was one of the first species to be utilised by the
early settlers in the neighbourhood of Port
Jackson, for bridging, house building, piles and generally where great
strength and durability were required.