From the first time humans went from Point A to Point B, there was, apart from not being eaten and finding the way back, a paramount consideration – clearing the way forward.

We tend to think of urban and civilized growth as constant, but it’s Mother Nature that is truly perennial. Look to the growth of greenery near your own home – from lawn to weeds to that tree out front by the road. Vegetation is pretty persistent.

That’s a blessing, but it also presents challenges when growing a transit network that has to work in harmony with greenery that doesn’t care about staying back from yellow lines or rail tracks.

This is a bit of an explanation about finding that balance with nature – while keeping customers safe.

Metrolinx’s current GO Expansion program is the largest transit infrastructure program in Canadian history.

To expand corridors, build new infrastructure and run more trains, Metrolinx is looking to contractors to trim, remove and replace vegetation through sections of its rail corridors and, in some cases, adjacent properties.

Managing the trees and vegetation as part of rail service expansion isn’t new. It’s actually quite a fundamental part of maintaining a safe rail corridor and running services that are punctual and efficient and in this case – a GO Expansion program requirement.

Customers don’t often notice this work taking place.

In addition to what you might think of as traditional corridor maintenance – replacement of rail ties and rail sections, inspection of bridge structures, and updates to signal software – making sure trees and vegetation don’t impede sightlines or access to rail equipment are equally important keys to safe rail operations.

Keep in mind, GO Transit operates across a huge swath of Ontario – covering the most populated string of urban communities in the country. That’s a lot of branches reaching out.

Given the scale of vegetation and tree removal effort anticipated to accommodate GO Expansion, Metrolinx has been working closely with local regional conservation authorities – Toronto Region Conservation Authority (TRCA), Lake Simcoe Region Conservation Authority, Conservation Halton, municipal partners, and other organisations. It involves providing compensation that offsets the ecological impacts of this work and ensures that the interests of property owners are looked after.

“TRCA is pleased to partner with Metrolinx to address ecosystem compensation requirements as a result of tree and vegetation removals with Metrolinx’s GO Expansion program,” said John MacKenzie, chief executive officer for the Toronto and Region Conservation Authority.  “TRCA staff are collaborating with Metrolinx on long-term opportunities related to reforestation and GHG (greenhouse gas) emission offsets to assist in advancing Metrolinx’s agenda for both sustainability and climate risk.”

How does Metrolinx’s vegetation compensation strategy work? It’s largely based on one or a combination of the following three approaches:

Baseline Compensation – The approach to baseline compensation is anticipated to apply to Metrolinx property and properties that do not have an applicable municipal by-law. Trees removed would be replaced on a one-for-one basis.

Bylaw Compensation for Public/Private Lands – Trees within public and private lands, including those on the boundary between Metrolinx and those properties, will be compensated based on applicable by-laws and regulations. If no by-laws or regulations apply and the tree is not in a ‘Designated Natural Area’, public/private landowners will receive baseline compensation to replace the removed tree.

Designated Natural Areas include natural heritage systems and features that support natural processes and are identified by resource agencies, municipalities, the government and/or public through legislation, policies or approved management plans.

 Ecological Compensation – Trees within a Designated Natural Area will be compensated through ecological restoration reflecting the principles of the TRCA Ecosystem Compensation Protocol approach. The approach focuses on the creation or enhancement of habitat and will be scientifically calculated to replace the loss of ecological functioning.

“Building a safe transit network is a priority for us here at Metrolinx,” said Matt Clark, Metrolinx’s chief capital officer.

“That being said, it is also our responsibility to ensure we are meeting our own sustainability goals. That is why I am pleased that by working with our municipal and conservation authorities we have been able to develop a compensation program that balances our need to deliver new infrastructure and operate new services while maintaining an effective ecosystem around our region.”

Once vegetation is removed within the rail corridors, Metrolinx’s replanting approach will protect the transformed infrastructure and new service schedules into the future.

Where needed and when possible, Metrolinx will establish an approximate seven-metre vegetation exclusion zone, where growth will be limited or restricted and include management of invasive species and promote growth of native and pollinator species.

This space is needed to run lines safely.

This will limit the frequency and intrusiveness of future vegetation control, which currently includes mechanical cutting, and manual brushing and mowing. This proactive approach to vegetation management for future train operations was originally identified as part of the GO Rail Network Electrification 2017 Transit Project Assessment Process (TPAP).

When summer comes, and you look at your overgrown front lawn, you may tend to see it as the better part of a Saturday morning sweating it out.

But for Metrolinx experts, vegetation is divided into zones. Here’s how they see it.

Zone 1: This zone is 2.9 metres from the centerline of the track to the Overhead Contact System (OCS) poles. No vegetation is allowed here because it conflicts with where the trains will be running.

Zone 2: This zone is 2.5 metres and falls immediately outside the OCS poles. No vegetation is allowed here because of potential conflicts with the electrical infrastructure.

Zone 3: This is a 1.6 metre wide low growth zone where vegetation up to a height of 1.4 metres above track level will be permitted. For Metrolinx-owned property, the following approach will be taken to vegetation removal and replanting in Zones 4 and 5. Where Metrolinx does not own the property in Zones 4 and 5, no changes to the property will be required (unless deemed hazardous).

Zone 4: This is a 5.5 metre wide area outside of the vegetation clearance zone. In cases where this zone is being replanted, the new vegetation will be species that grow to medium height (4 metres above track level).

Zone 5: This zone is a 3.5 metres wide area outside of the vegetation clearance zone. In cases where this zone is being replanted, it is recommended for new vegetation to be species that grow up to 8 metres above track level.

Through its compensation initiative, Metrolinx is expecting to successfully replace or compensate for all of the trees that will have to be removed during future GO Expansion work, while making every effort to repurpose the more valuable trees instead of disposing of them.

High-value wood, for example, will be diverted to local organizations and communities. The rest is largely turned into wood chips and mulch.

In cases where removals may be required on private properties, the owners will be contacted individually to determine the appropriate scope and compensation options.

Vegetation removals will be phased in throughout the GO network over the next few years but officials are planning for early tree planting and compensation work to begin this coming spring.

But the work will go on and on, as nature looks to stretch out into transit routes and lines, and Metrolinx continues to make sure there’s a clear path forward.

To find out more about Metrolinx’s GO Expansion program, just go here.

To find out more about Metrolinx’s sustainability program visit here.