METRONET Byford Rail Extension’s Urban Forest Strategy – Social Outcomes

The Byford Rail Extension Project (BRE), delivered by the MetCONNX Alliance has demonstrated outstanding commitment to stakeholder and community contribution through improving ecological and social outcomes in the production of a meticulous and extensive tree retention and planting strategy. This project represents a once-in-a-generation opportunity to revitalise the existing Armadale City and surrounding neighbourhoods along the rail extension to Byford, by creating new train stations, elevated rail removing level crossings, and providing high-quality community open spaces.

Existing trees enhance the community’s sense of place, provide shade, mitigating the ‘urban heat island effect’ and supporting health, aesthetic, and environmental outcomes. Early on, MetCONNX recognized the importance of trees to external stakeholders and developed a robust tree retention and planting strategy as a legacy for future generations. Acknowledging the critical role trees play in urban ecosystems, MetCONNX implemented a comprehensive approach to minimize impacts on tree cover while fostering positive community engagement and collaboration.

A Tree Working Group (TWG), consisting of arborists, environmental professionals, urban planners, designers and construction leads, developed the strategy, guided by surveys and vegetation modelling in GIS software. Each tree was mapped and assessed for their health and species. This data was then used in project planning, adjusting the rail alignment and construction methods to avoid root zones and minimize clearing. MetCONNX’s tree retention vision was built on three pillars: careful planning, community involvement, and continuous monitoring.

The principles of MetCONNX’s approach to tree retention, protection and selection of trees for landscaping has included:
• working collaboratively with local government to retain, protect, and select trees.
• maximise the retention and protection of existing mature and heritage trees.
• increase tree canopy coverage within a defined time period.
• replace tree species ”like for like”.
• procure a minimum 50% endemic tree species.
• enhance diversity in tree selections.
• utilise mature tree planting stock for use in high amenity areas with greater tree removal.
• improve visual amenity through screening of noise walls and viaducts to minimise scale and visual impacts.

A proactive approach to stakeholder engagement was the cornerstone in maintaining transparency and securing buy-in. This was executed through regular information sessions, workshops, and consultation that gathered feedback to address concerns and refine design/planning outcomes. Input from these sessions directly influenced our tree retention strategy, building trust and support with external stakeholders. The legacy of this is the preservation of green spaces in alignment with community aspirations. Taking it one step further, reinforcing our tree retention efforts with native flora for landscaping and rehabilitation contributes to regional environmental goals of increasing tree canopy.

Effective collaboration with community stakeholders has culminated in the TWG having significantly improved the number of trees that are now able to be retained through:
• changes in design and construction methodologies;
• canopy pruning and management to minimise impacts; and
• relocating service infrastructure, lay-down and access areas to areas with less ecological impacts.

This has driven positive outcome for both sustainable environmental management and stakeholder engagement on the Byford Rail Extension project.

In close collaboration with external stakeholders, the preservation of as many mature trees as possible has prioritized environmental and social sustainability outcomes on the Project. Design and construction options and progress was workshopped with local councils over many months. This began as a regular agenda item in local government presentations but evolved into dedicated sessions until an agreement on the strategy and its objectives was reached. After the strategy was developed, local government has retained final approval on proposed changes as construction progresses.

Whilst it is acknowledged that not all trees were able to be retained due to the nature of construction works, the TWG has significantly improved the number of trees retained due to the following initiatives:
• Viaduct construction methodology was revised to minimise cranes and other plant impacts, avoiding the clearing of 22 mature trees.
• Design optioneering for the Armadale Rd PSP bridge to be built as a tight double helix structure (as opposed to the long loop structure originally considered) to minimise land take.
• Micro-tunnelling for relocation of Western Power services, meaning trees were pruned rather than removed.
• Relocating service infrastructure, lay-down areas and access tracks to lessen impacts to trees.
• Installing tree and root protection zones.
• Initiating watering programs throughout summer months.
• Securing additional project funding to facilitate early procurement of >1000 semi-mature trees for project landscaping, as opposed to planned tube-stock. These trees will be complimented with extensive endemic, drought-tolerant garden beds.
• All local heritage trees have been retained.

As a result, the following outcomes have been realised to date (noting this is every evolving as works progresses):
• 110% improvement in tree canopy retention, representing >37,000sqm of canopy.
• 603 trees retained of a total 1152 under consideration for clearing.
• 1,870 trees to be planted of which, 22% are semi-mature.
• 11.82 Ha of vegetation landscaping and rehabilitation will replace expected 8.97 Ha of vegetation cleared. This represents 44% saving of the approved Project clearance area.
• Careful removal of 536 culturally significant Grass Trees (Balga), which are to be transplanted back into the project footprint, post construction.

A core focus of the local community was maintaining and improving tree canopy across the project footprint, to align with urban forest strategies. Therefore, tree canopy was also modelled and assessed to identify improvements. Modelling has projected canopy coverage targets to be exceeded, particularly within the Armadale Station precinct as follows:
• 18.78% canopy coverage existing prior to project commencement.
• Early planning estimated 64% canopy clearing at reference design, leaving only 6.68% coverage.
• Iterative design and construction methodologies has now demonstrated 12.2% canopy coverage to be retained.
• Post 5 years practical completion, projected canopy coverage to reach 20.14% and 32.18% at Post 20 years practical completion.

It is widely accepted that in an urban setting, vegetation, particularly trees, provide important social benefits. MetCONNX are not only retaining but enhancing the ‘urban forest’ which will beautify the local environment and create a sense of place within communities. In an increasingly hot, dry climate, these trees will provide shading and relief for pedestrians. New public space, unlocked by the elevation of the rail, combined with planting of semi-mature trees, will also benefit the physical and mental health of local community.

The development of the strategy with the local government facilitated a truly collaborative design of the asset, with the end-user in mind. It responds to community stakeholder preference of green spaces and tree retention. The outcomes of our tree retention strategy were both impactful and far-reaching, reflecting the success of our integrated approach to preserve and enhance local ecological features whilst maintaining a collaborative relationship with key stakeholders who have played a critical role in project decision making in a key focus area.

The local community are the major beneficiary of our tree retention strategy. The preserved (and eventually improved) tree canopy enhances neighbourhood aesthetics, provides cooling shade, and improves air quality. It is widely accepted that greenery offers several mental health benefits. Local government surveys highlight increased satisfaction with local green spaces, contributing to a greater sense of well-being and connection to the environment. Through our own engagement, MetCONNX identified very early in the project that a priority issue for the community was tree retention and public green spaces to be delivered in the final asset.

Local Governments The City of Armadale and the Shire of Serpentine Jarrahdale benefited from our alignment with their environmental policies, particularly in urban greening and sustainability. Our preservation of mature trees supported their regional urban forest strategies and thematic heritage values, particularly in Armadale where heritage trees are highly valued by the community. MetCONNX worked hard to avoid clearing any of these heritage trees as well as significant reductions in land clearing by ~44% from approved regulatory allowances. MetCONNX’s challenge of ‘Business As Usual’ approach to design development and project delivery improved external stakeholder relations, particularly with local governments, through extensive consultation and input into design and delivery methodologies.

Alliance Partners experienced strengthened relationships as a result of the collaborative approach taken to gain buy-in. By working closely with local governments and community groups, the Alliance reinforced its commitment to sustainable development, gaining recognition for its leadership in environmental conservation.

Alliance partners have also benefit from having a tried and tested methodology for tree retention/preserving biodiversity. Early project phases such as at bid phase and reference design will benefit most from early adoption of these tool and methodologies to assess asset design options with the least impact on local ecology. This will also help our Clients with environmental approvals compliance, reducing spending on ecological off-sets, and aligning with industry targets for net-positive biodiversity action. Laing O’Rourke, our delivery partner, has since used this tool in future-project bids to align with the growing importance of nature preservation.

The collaborative efforts of each of these groups meant that tangible benefits from the tree retention strategy and planting strategy could be experienced by all. The evolution of the strategy contributed to a more sustainable and harmonious integration of new rail infrastructure within the local community and leaves a positive legacy for future generations.

A tangible legacy has resulted from the actions of this project which extends beyond the immediate preservation of trees. It represents a model of what is possible when integrating large-scale infrastructure projects with sustainable environmental practices that demonstrates beneficial, measurable and enduring outcomes for people. The approach accomplished has set a new benchmark for future infrastructure developments, proving it is possible to achieve significant environmental and social outcomes without compromising project delivery. Importantly, this initiative demonstrates that collaboration with external stakeholder in response to priority issues can facilitate greater engagement to achieve aligned objectives where involvement in significant decisions during design and planning are accommodated. As a result the outstanding Project outcomes that respond to specific United Nations Sustainable Development Goals, are detailed as follows:

Goal 11: Sustainable Cities and Communities
This initiative has directly contributed to creation of sustainable urban environments by preserving green spaces, improving air quality by mitigation of extensive clearing of mature vegetation, as well as enhancing community well-being. The station precincts will also provide universal access to green infrastructure in public spaces, significantly improved from prior to construction.

Goal 13: Climate Action
By maintaining and protecting large-scale established trees combined with mature endemic trees procured for landscaping, we have supported climate action efforts through carbon sequestration and mitigation of urban heat island effects through canopy coverage that provides mitigation on hot days.

Goal 15: Life on Land
The action MetCONNX has taken to protect and restore terrestrial ecosystems is inherent in the tree retention and planting strategy preserving local biodiversity conservation of endangered fauna and flora species such as endangered Black Cockatoos and the Kingia australis, as well as threatened ecological communities, wetlands, and Bush Forever conservation sites. Every tree and ecological habitat retained, halts the degradation of natural environments and preserves diverse forms of life on land and efforts to protect, restore and promote the conservation and sustainable use of terrestrial biodiversity.

Planting selections for final landscaping have prioritised endemic species to the area, with at least 20% providing foraging habitat for endangered Black Cockatoos. Maintaining and mimicking wetlands with bio-swale infrastructure provides a home for foraging habitat for wetland species such as frogs.

The learnings from this project have been embodied in the creation of the ecological visualisation tool and associated weightings calculator. These tools are now a blueprint for this outcome to be replicated and accelerated on future projects.

Goal 17: Partnerships for the Goals
The collaboration with local governments, community groups, and alliance partners exemplifies the power of multi-stakeholder partnerships in achieving shared sustainability goals.

Overall, our tree retention strategy has established a lasting impact on both the local environment and community, exemplifying the benefits of integrating sustainability into large-scale infrastructure projects and contributing to the broader global agenda of sustainable development.