Trees on campus provide shade, amenity and have immense habitat value. There are approximately 4500 to 5000 trees within the landscape spaces of the campus and an estimated 20,000 more in the adjacent bushland on the escarpment and in the riparian corridors. In under 50 years the university has transformed this site from a cleared farmland with limited remnant vegetation to what it is today.
There are a number of trees on campus that were present onsite when it was still farmland prior to the 1950s. These are significant trees including the Turpentine near the P3 multistorey carpark and also the Turpentine surrounded by the decking near Building 13.
As dynamic living structures trees grow, mature, decline, and die. They are also susceptible to diseases, man-made interferences, and damage from weather events that can affect the structure and lifecycle of trees.
To manage these risks and values a tree management system called Arbor Plan is used to guide tree maintenance, manage safety risks, assess and retain habitat and identify significant trees. Trees that have been tagged and numbered are listed in this management system. These trees are in the populated and frequented areas of the campus and scheduled inspections are conducted to monitor tree health.
Tree maintenance works are conducted in a manner that balances the trees values and safety risks. As part of our tree management we monitor tree disease and manage faults to prolong the requirement to remove a tree and maintain habitat values. Methods used include:
- Sonic tomograph testing - this test provides data on the ratio of sound structural wood to decaying wood in trees identified as having fungal rot. This test allows us to monitor the rate of decay and prolong the need to remove the tree for many years.
- Installing branch support hardware - this hardware is used when major faults are identified in large significant trees and the probability of failure is high, cabling systems are installed that support the fault and allow the tree to create wound wood and strengthen the wound area. This type of intervention has limitations and can only be used in some circumstances.
- Remedial pruning - these works include fault removal weight reduction and corrective pruning.
- Habitat management - current and potential habitat values are assessed and managed in a manner (when possible) that removes the safety hazards but retains the habitat values. In some instances there may not be an existing hollow but one is created in the remaining trunk or a possum box installed. When a tree is required to be completely removed some sections of trees are placed in nearby gardens and bushland for use as habitat and the remainder of the tree is chipped and used on site to mulch garden beds. We continue to plant trees on campus replacing all removed trees with a focus of maintaining and enhancing tree canopy and habitat.