THE MORETON BAY FIG TREE on HENRY STREET, TOOWOOMBA

The Moreton Bay fig tree at the east end of Henry Street, Toowoomba.

The two trees in the background are large Chinese elms

The Moreton Bay fig tree at the eastern end of Henry Street in Toowoomba is the finest specimen of its species in the city. The tree is on private Federal Defence Department land and should not be approached more closely than the gate, which anyway gives a very good view of the tree. The tree was planted by Eric Albury French of Toowoomba before he left to fight in the First World War, ‘to be remembered by’. Eric French became a Warrant Officer 2, fought in France, and returned safely from the war.

The tree is one hundred years old. The trunk is two to three metres thick, and the canopy is 27 metres wide and 24 metres tall.

Moreton Bay figs (aka Port Jackson figs in New South Wales) occur naturally along the east coast of Australia in wet and dry rainforest, and in south-east Queensland reach their furthest inland location along the Great Dividing Range. They are commonly massive and magnificent trees, typically with several short thick trunks arising from a wide spread of buttress roots. The trees generally develop low thick wide-spreading branches close to the ground and an immense rounded canopy of large leathery dark green leaves. Spherical green flowering bodies (syngonia) develop among the new leaves in spring, and ripen into edible mottled purplish fruits about two centimetres across in late summer.

The tiny seeds of Moreton Bay fig trees are spread by fruit-eating birds, bats and possums. They may either germinate in the ground (like this tree) or in the canopies of other trees, in which case they become strangler figs. The trees that develop from seeds that germinate in the ground vary considerably in form, sometimes with and sometimes without spreading buttress roots, some with single tall slender trunks, others with short thick trunks which branch into upward-spreading subsidiary trunks, and some growing into the more classical shape of this tree in Toowoomba.

Moreton Bay fig seedlings that germinate in the forks of other trees send down slender aerial roots to the ground which later thicken, branch and fuse together around the trunks of their host trees until they form such a tight outer layer that the host tree is eventually strangled and dies. Toowoomba’s climate is too dry for any of the native fig trees to develop prop roots descending from horizontal branches to the ground.

Moreton Bay fig trees are not only impressive and beautiful, but they are also very important sources of habitat and food for a wide range of local native fauna; they may also be hosts to epiphytic ferns and other plants. Whilst their leaves and fruits are consumed by a variety of insects and their dead wood by termites, their greatest ecological value is the ripe fruits which provide food for many species of native birds, bats and mammals, all of which spread their seeds.

Moreton Bay figs (and all other species of figs) have unique flower and fruiting bodies called syngonia. Syngonia are spherical, with an internal cavity lined with hundreds of minute male, female and sterile flowers. The cavity is connected to the outside by a narrow passageway lined with backward-pointing hairs. During the development of the syngonia tiny wasps which are specific to each species of fig enter them through the narrow passageway. Trapped inside, the wasps move around, mate, lay eggs on the sterile flowers and pollinate the female flowers (resulting in the seeds inside edible figs). The wasp grubs feed inside the ripening fruits then eat their way outwards, pupating under the skin before escaping as adults to seek out other developing syngonia to enter.

(Article by John Swarbrick)