Rough bark types
Ironbark: hard, compacted, furrowed; over whole
Perhaps the easiest bark to recognize is that of the traditional
ironbarks. In these species, the rough bark becomes hard, compacted
and furrowed with age and varies in colour from grey to black or
red-black. Some ironbark species, however, have all the appearance
of the hard, furrowed ironbark character, yet the bark is actually
soft and somewhat flaky and friable as in some forms of E. fibrosa and E.
placita. Therefore, the ironbark character may refer more to
appearance and expectation rather than to fact! In some species of
unrelated groups (e.g. E.
aromaphloia, and E.
indurata) the rough bark may be thick, hard and furrowed
as in the ironbarks.
Tessellated: red bloodwoods, yellow
bloodwoods, ghost gums
The outer dead bark breaks up into small flakes (tesserae or tessellations).
This bark may be loose or firmly held to the whole trunk and branches.
In bloodwoods, when the outer, most weathered flakes are lost
by attrition, an orange and brown mottling of the newly exposed
underbark is often produced. The texture of the rough bark is
somewhat corky. Among the red bloodwoods, particularly inland
and desert species, the tessellated bark is not retained over
the whole trunk (e.g. E.
chippendalei). The flakes are looser and are most prominent
on the lower trunk while the upper trunk is often smooth. There
is no wholesale shedding of the flakes in these bloodwoods and
the trunk remains permanently and colourfully mottled. There is
a smaller group with tessellated bark (yellow bloodwoods) in which
the outer, unshed bark is always loose but remains attached covering
the whole trunk and branches. The outermost layers weather to
light brown or greyish brown or shades of faded yellow but are
readily lost by attrition exposing the underlayers which are bright
yellow to golden such that the yellow bloodwood trees in a forest
of mixed species can be easily seen from a distance. Examples
peltata and C. eximia. While this type of bark
characterizes the yellow bloodwoods, it also occurs (though often
less spectacularly) in the unrelated northern species E.
lirata and E. cloeziana.
Another group, (ghost gums), has a
distinctive type of tessellated bark or lacks rough bark altogether.
Some species are completely smooth-barked (e.g. C.
others have a basal stocking of distinctive tessellated rough bark
with an abrupt cut-off line on the trunk (e.g. C.
tessellaris). Even in the smooth-barked species, the tessellated
nature of the bark is often revealed after fire when the newly killed
basal bark breaks up into rough flakes which are then shed. Box species
often have some tessellated rough bark (e.g. E. bridgesiana, E. moluccana,and E. hypostomatica).
In the grey box, white box and black box groups, the outer rough
bark is rough, usually firmly held, somewhat fibrous though compacted,
and ultimately breaks up into small tessellations. When the outermost,
that is, the oldest part of the fragments fall away, unweathered
whitish inner bark is exposed giving a dark, grey and white mottled
pattern to the whole trunk. In large old box trees the rough bark
often becomes looser, shaggy and furrowed, particularly towards the
Stringy or fibrous: stringybarks, peppermints,
This is a large group of species that can usually be recognized
by the thick, longitudinally-furrowed, fibrous bark over the whole
trunk such that the bark can be pulled away in long strings, ie.
stringybarks (e.g. E. macrorhyncha) and some other species
(e.g. E. cinerea, E. pellita and Angophora
floribunda). The inner layers of stringy or fibrous bark can
usually be seen to be criss-crossed. In some mallee species belonging
to the group, the stems may be mostly smooth but the characteristic
stringy bark can usually be seen towards the base. The outer rough
bark weathers to greyish but on stripping the rough bark away, the
underbark will usually be found to be a rich reddish colour. Some
stringybark species have the rough bark to the small limbs, but a
few have notably smooth branches (e.g. E. blaxlandii). In
another large group, the peppermints, the bark is rough over the
trunk and often the branches. The rough bark is similar to that of
the stringybarks but is thinner and does not become coarsely furrowed
in the old trees and the criss-cross pattern of the underbark is
often conspicuous. A small group, the white mahoganies e.g. E.
acmenoides, is notable for the rough fibrous bark being held
more or less in flattish strips, rather than loose criss-cross fibres,
although the character is difficult to categorise unambiguously.
This type of rough bark is also seen conspicuously in the famous
Western Australian endemic, jarrah (E.
marginata). The stringybarked bloodwood, C. jacobsiana, from the Northern Territory is another example of a type of finely
Box: short-fibred, grey, sometimes mottled
grey and white or even brown-yellow
The boxes e.g. E. populnea, E. microtheca, are one of the most difficult groups to summarize. The bark is often tightly held,
sometimes tessellated (see above), but may, in some species, be quite
flaky. Thickness is variable and shedding is irregular or in many
species does not occur at all. The boxes are a large group of closely
related species, but box-type bark also occurs in other distantly
related species (e.g. E. angophoroides).
Imperfectly shed ribbons, strips or
The bark on the stems, and possibly the larger limbs, appears
loosely rough, due to the imperfect shedding of dead bark. The
general appearance is quite variable depending on whether a given
species normally sheds in long coarse ribbons, shorter thin strips
or in irregular flakes. For example E. horistes often
has a rough trunk clothed in coarse, partly detached ribbons which
hide the living bark; E. praetermissa has its trunk lightly
covered with thin short strips of dead bark; and E.
astringens has a trunk that is often almost smooth but
seasonally may have numerous small rough curling flakes of dead
bark adherent to the surface giving a scruffy appearance.
The 'imperfectly shed ribbons, strips or curls' should
not be confused with 'loose basal slabs' which implies
a thicker accumulation of dead bark usually on the lower stem
A few species (e.g. E. elata) have rough bark for the basal
1-3 m only. They may be known as blackbutts. This originally fibrous
bark becomes suffused with exudates and hardens the bark somewhat
similarly to the unrelated ironbarks. The bark colour is invariably
very dark brown to black. In E. sieberi this type of bark
may cover the whole trunk and be quite fissured or furrowed, while
the branches are conspicuously smooth.
Loose basal slabs: apparently rough, particularly
the lower bole
All smooth-barked species shed their dead bark at some time. Many
species, particularly in cultivation, hold some of their dead bark
loosely over the bole for some time before it is shed. Particularly
old individuals may also exhibit this character. This type of 'rough' bark
is to be distinguished from distinct, firmly-held rough bark. Clearly,
this is an ambiguous bark type which takes experience to assess.
If no decision can be made, this and another bark form should be
selected, or the rough bark character bypassed altogether.