Tree growth is strongly influenced by below-ground conditions. Tree roots are opportunistic and will proliferate wherever moisture, aeration, nutrition and soil structure are favourable. Tree root growth in the urban environment is highly modified and is not governed by property boundaries.
There are a number of common conflicts with tree roots in the built environment:
Direct damage
Direct damage is the distortion of built structures as the growing tree root exerts pressure. Direct damage by tree roots is usually limited to light built structures such as pavements and low walls and can also be witnessed in buildings of sub-standard footings.
Indirect damage
Indirect damage is the distortion of built structures as the growing tree root takes up soil moisture. Often there are multiple factors contributing to foundation movement and are seldom associated with tree root growth alone. For this reason, claims of indirect tree root damage must be accurately investigated.
Leaking pipes (as a result of poor construction, old earthenware, cracked and faulty joints and degradation) can create a moisture gradient that encourages tree root growth in the direction of the pipe.
The property owner is responsible for the maintenance, repair and replacement from the legal point of discharge, usually near the property boundary kerb. The City of Melbourne should always be given the opportunity to inspect the pipes and offending tree roots prior to the property owner undertaking repair works.
City of Melbourne will seek to resolve tree root conflicts as follows:
- All claims of tree root damage from public trees will be investigated.
- City of Melbourne will seek practical solutions to reduce the risk of damage to infrastructure from public trees.
- Tree removal will only be considered if no practical arboricultural solution can be found.
- Every effort will be taken to ensure that replacement and future public trees will not themselves result in similar damage to built structures.
- If tree root growth causes foundation movement, City of Melbourne will seek a viable arboricultural solution to rectify the situation and to retain the public tree.
- Claims of property damage from tree roots must comply with City of Melbourne guidelines for submitting a claim.
- City of Melbourne will not remove public trees for unjustified claims of pipe or sewer damage from tree root activity.