Biology experiment helps historic UNSW fig trees put down new roots

A group of students, staff and researchers are applying some creative thinking to preserve iconic fig trees on UNSW Sydney’s Kensington campus.
Ivy Shih | UNSW Newsroom

University students, staff and researchers have found a possible solution to protecting the heritage listed fig trees on the campus.

Visitors to the University in the past year might have noticed a curious cluster of white plastic pipes at the base of some fig trees on campus.  The pipes are the work of the UNSW community to encourage the growth of the ‘aerial’ roots of fig trees – thin roots which grow down from branches and ultimately reach the ground to become new trunks.

The Moreton Bay and Port Jackson Fig trees at Kensington – estimated to be older than the University at up to 120 years old – are more than 30 metres tall, with a canopy stretching more than 35 metres.

The trees line one of the lower campus roads, forming a leafy backdrop to University landmarks such as Fig Tree Lane and Fig Tree Theatre. 

Not only had the aerial roots reached the ground, they had intertwined and anchored into the soil to form a firm foundation.

Interestingly, the root length of the control group remained unchanged.

“So many undergraduate practical classes involve students running through exercises for which the answers are already known,” Professor Moles said.

“It was awesome being able to break out of that mould and use a class exercise to address a real-world problem and discover something totally new.”

Biology student Suzanna Gooley was part of the original class that set up the experiment and returned to the site.

“It’s really exciting, as it suggests that maybe our idea was correct and it was actually the humidity and the water that helps the roots reach the ground,” said Ms Gooley, who is in her final year of study.

“Some of the roots were two metres off reaching the ground and have grown to the soil in the 12 months since, so that’s absolutely amazing. Especially when comparing to ones which have had no treatment.”

The experiment gave Ms Gooley a new-found appreciation for the Moreton Bay and Port Jackson Fig trees, which have the botanical names Ficus macrophylla and Ficus rubiginosa.

“Honestly, I always thought the fig trees were nice but I never thought too much about them,” Ms Gooley said.

“Now I feel like I know these trees better and I appreciate the amount of effort that goes into keeping them on campus and keeping them safe.”

The class will submit the results to a peer-reviewed journal.