Exotic trees like Camphor Laurel and Chinese Elm dominate stretches of our waterways and can be costly to remove, both financially and environmentally. A long term, low impact and cost-effective alternative is to use native figs that strangle their host as they reach maturity.
Not all figs have strangler tendencies. Suitable species from South East Queensland include the Strangler Fig (Ficus watkinsiana), Moreton Bay Fig (F. macrophylla), Small-leaved Fig (F. obliqua), Port Jackson Fig (F. rubiginosa), Deciduous Fig (F. superba var. henneana) and White Fig (F. virens var. sublanceolata).
The fruit of strangler figs are consumed by birds, possums, bats and rats, and the seeds may be deposited in the forks of trees. Accumulated biomass and a damp microclimate help germinate the seed. The seedling starts off as an epiphyte growing slowly until the roots reach the ground. As more of the roots reach the ground, they eventually enclose around the tree until all that is left is the fig and a decaying host tree. This process can take decades and in some cases centuries however, the plan is to speed up this process.
Land for Wildlife Officers from the City of Moreton Bay have have pioneered an innovative technique that skips the slow epiphytic stage by encouraging long healthy root growth in PVC pipes. This quickly allows the roots to reach the ground and aids in the attachment of the seedling fig to the trunk of the host tree. This method allows for the grower to continue watering and providing nutrients to the fig.
It is recommended that a slit is put into the back of the PVC pipe to allow expansion and removal of the pipe once the strangler fig roots are established.
This technique has shown signs of success with evidence of roots beginning to attach to the host. The hope is that this technique will see an acceleration in the process and maybe the planter will reap the rewards.
Photo at top: Josh is standing next to a native fig that is starting to strangle a mature Blue Gum tree. Over many decades, the fig tree may totally strangle and replace the Blue Gum.
Article by Josh Pethtel
Land for Wildlife Officer
Ipswich City Council
Photos by Stefan Hattingh, City of Moreton Bay