Eucalyptus Size and habit
A Eucalyptus may be mature as a low shrub or as a very large tree.
There are three main habit and four size categories that species can be divided into.
As a generalisation "forest trees"
are single-stemmed and have a crown forming a minor proportion of the
whole tree height. "Woodland trees"
are single-stemmed although they may branch at a short distance above ground
level.
"Mallees" are
multi-stemmed from ground level, usually less than 10 metres in height, often
with the crown predominantly at the ends of the branchlets and individual plants
may combine to form either an open or closed formation. Many mallee trees may be
so low growing as to be considered a shrub.
Apart from the forest tree, woodland tree, mallee and shrub habits two
further tree forms are notable in Western Australia. One of these is the "mallet", which is a
small to medium-sized tree, usually of steep branching habit, sometimes fluted
at the base of the trunk and often with a conspicuously dense, terminal crown. It is the habit usually of mature
healthy specimens of Eucalyptus occidentalis, E. astringens, E.
spathulata, E. gardneri, E. dielsii, E. forrestiana,
E. salubris, E. clivicola and E. ornata. The smooth bark of mallets often has a satiny sheen and
may be white, cream, grey, green or copper.
Another habit category used in Western Australia is the "marlock". This has been variously applied but Brooker
& Hopper (2001) defined the term and restricted the use to describe the more
or less pure stands of short, erect, thin-stemmed "trees" that do not produce lignotubers. These are easily seen
and recognised in stands of E. platypus, E. vesiculosa and the
unrelated E. stoatei. The marlock is distinguished from mallets which are
taller and have a characteristic steep branching habit. The origin and use of
the term "morrel" is somewhat obscure and appears to apply to trees of the
western Australian wheatbelt and goldfields which have a long, straight trunk,
completely rough barked.