The aim of this article is to describe and examine contemporary tree root management practices in the City of Yarra, Victoria. The current high density of structured infrastructure, primarily Victorian dwellings, the intensive planting of native trees and reactive clay soils often creates conflict between such needs and local infrastructure. The conflict often manifests as aesthetic issues with the loss of key tree habitat and associated land use practices. This paper was undertaken to describe and analyze the current practice of tree root control within the City of Yarra, Victoria. The paper then presents the current practice and its impacts on both the quality and quantity of local ecological environments.
There are numerous examples of how tree planting and root Tree Management work in the City of Yarra, Victoria. A case study is the controversy highlighted in Part 1 of this article concerning the loss of sustainable Agricultural Land in the City of Yarra due to the inappropriate tree planting practices of the previous council. The City was created in the late parts of the 1800s as a consequence of the Industrial Revolution and excessive land clearing. A consequence of this was an increased flood of non-native and harmful tree pests into the City’s environment, which were initially not removed through traditional tree planting practices. These practices were inconsistent with the objectives of the creation of the City of Yarra and in most cases resulted in the death of valuable plant species.
The City’s primary objectives were to protect existing sustainable agricultural land and to promote the economic production of local agriculture by supporting improved access to capital resources and improving environmental quality. A significant constraint posed by the lack of suitable trees for planting was the issue of tree root management. The Council was required by legislation to ensure that adequate tree planting and management strategies were put in place to mitigate the negative effects of tree clearings on the environment.
The Council has a range of tree planting programs in place to achieve its objectives, the first of which is tree root management where the Council’s vegetation and environment managers plan the tree planting, tree removal and manage tree roots in relation to those objectives. The first program to implement this method involved the establishment of a tree planting programme based on the assumption that existing farm lands should be cleared so as to provide room for a new integrated urban forest. The planning process was undertaken via a participatory approach where local residents were invited to participate in the process of plant establishment and management. Subsequently the planted trees have gradually grown in number and the Council has been successful in maintaining a sustainable tree root system by ensuring effective tree growth and healthy tree root systems.
The second program, the Integrated Management System, involves the utilisation of an integrated pest management approach to control destructive pests and to improve the health of the Australian trees. It has proven successful in providing tree root systems that are free of disease and have a stronger root system. This is achieved by the consistent use of disease-specific treatments and controlled pest densities. These methods help to ensure that tree diseases do not threaten the established tree plantations and by controlling the pests that do become a problem the Council has been able to protect them from a widespread loss. The integrated pest management approach has helped to protect the regional economy as well as achieving environmental objectives.
One of the other aspects of tree root management that the Council has been successful in achieving through their strategies is that of soil preparation and clay soils. Tree planting takes place over poor soils that may have lost their moisture content or become compacted due to climate conditions. This then reduces oxygen availability to the root systems. The Council has successfully used its tree planting strategy to create conducive environments for trees to grow and flourish in both clay soils and soil that has had some amount of disease treatment.