There’s More Than One Way To Save a Street Tree
(Source: Pixabay.)
The only thing worse than losing a mature street tree to disease is losing a mature tree to construction.
This I can say with confidence, having spent hundreds of hours in discussion with other local proponents of the urban forest. Diseases like Dutch Elm are brutal, but we understand and accept that they are a reality we must live with and do our best to mitigate. But trees chopped down to make way for more development? That really makes folks’ blood boil: “Don’t developers know that preserving mature trees will make the property more valuable?“
The development of housing, roads, and other infrastructure leads to tree loss in most cities, prompting opposition by many folks who are passionately concerned about climate and biodiversity loss. This comes up time and time again at variance hearings and public engagement events …
When a tree comes down, a whole cascade of effects is triggered. The creatures that lived there must find new homes. The homes nearby will experience greater cooling and heating costs, and their shade gardens must be replaced by sun-loving ones. Traffic on the street goes faster. Plus, humans just tend to like trees. They look nice, they make us feel good. We miss them when they’re gone.
Here’s the challenge: most people can easily grasp the ripple effect that happens when a tree is lost. But, what gets overlooked is that a city is a system, too, and within it, every decision has the potential to create unexpected and unforeseen consequences. A healthy city grows and changes; it can’t stay the same. The decision NOT to change also has consequences.
Take infill. It’s rare to find a tree-hugger these days who doesn’t agree that the suburban development pattern must end. But there’s a big and messy gap between being opposed to greenfield development and embracing infill.
Here’s where it becomes critical to think in systems. What is the consequence of saying, “Sorry, we won’t be able to develop this lot or change the building because there are mature trees on it”? All it does is increase the pressure for housing at the edge of the city, in the form of unsustainable greenfield development, where housing is easy to build. (As the saying goes, squirrels and mice don’t have microphones and can’t complain.)
On top of the loss of natural habitat or farmland, suburban-style development further bakes in auto orientation. And this drives more environmental harm by requiring more parking, and ensuring more particulate pollution and more CO2 emissions.
The bottom line is this: the harder we make change within existing neighborhoods, the more pressure there is to raze existing lots to make them more appealing for quick and easy development, and the more pressure there is to do greenfield development. Neither of those outcomes is desirable.
Why do trees keep coming up against housing? If the presence of mature trees boosts the sales value of a property, why do they keep getting cut down? It has a lot to do with rigidity and inflexibility within zoning regulations. But luckily, it doesn’t have to be this way.
Parking Mandates
Simply put, let’s get rid of them.
The requirement to provide a certain amount of parking with every new project not only adds tens of thousands of dollars to the housing unit price, it uses a ton of valuable space that could be better used for more housing units, more amenities or, you guessed it, preserving or adding new trees.
Municipalities across North America are scrapping costly parking mandates, and, in their place, letting developers build what the market wants, or even enacting parking maximums.
Rigid Dimensional Standards
On top of mandated on-site parking with its prescribed amount and placement, in most places, there are countless other strict zoning rules that affect how the rest of a site can be used.
Setback and side yard rules dictate how far the building must be from the property lines, and how much space there must be between it and neighbouring structures. Building height and lot coverage maximums are further constraints the developer must work within while planning the home’s layout and configuration.
When the size and placement of buildings is rigidly prescribed, there is no flexibility to work around existing natural features on the lot. If in order to incorporate them, the building plans need a bunch of exceptions and variances, the project quickly ceases to be financially viable. It’s comparatively quicker and easier to just cut the trees down and start with a blank slate.
So, What Can We Do?
Land is finite. Trees are valuable, living infrastructure that can’t be truly replaced, only grown over many years. But here’s what I want my fellow tree advocates to know: when we say that trees must take precedence over housing, there are environmental consequences to that, too. The insidious, slow creep of ever-deepening auto-orientation is hard to see compared to the stark and brutal sight of a healthy tree being chopped down, but it is devastating on a far greater scale.
Here’s the good news: while policy has a major impact on urban trees, it’s within our control to change. We can choose whether our zoning policies help or hinder the urban forest.
As it turns out, the city of Ottawa, Ontario, has decided to do just that. In anticipation of a zoning by-law re-write, they published a series of discussion papers in 2023. One of those papers, “How Zoning Can Regulate Trees,” notes that “housing and urban trees need not be in competition, and both are better with the addition of the other.” Emphasis mine:
As infill occurs, there are significant pressures on the ability to retain existing trees, and an ‘order of priority’ that must be applied with respect to the many competing interests that accrue on an urban lot.
Ottawa has taken the approach that the most important thing is to add housing, but that trees are a higher priority than parking:
As previously noted, where the loss of a tree is in support of a greater quantity of housing, the public interest benefit accrued from the gain of new housing units is positive. However, trees will take precedence over parking and similar uses that rely on a large quantity of hard surfacing. This is particularly important to keep in mind in the case of trees in proximity to the footprint, which could potentially be retained through changes to the building design.
Flexibility in setbacks can play a key role in preserving existing trees:
… One potential option that could be considered is to add a degree of flexibility to the permitted envelope in support of tree retention. This could be expressed through adjustments to setback requirements: if it is necessary to increase the front yard setback a certain distance to protect a distinctive tree in the front yard, the rear yard setback could be reduced by an equivalent amount to permit the same-sized footprint in a manner that is more respectful of existing conditions with respect to trees. Building this flexibility into the by-law satisfies the need to retain ability to provide housing, while also accommodating the public interest value of the urban forest canopy.
On top of tweaking zoning, we can keep more trees standing through the careful and considered development of tree by-laws/ordinances, and by requiring robust construction best practices to protect trees and their critical root zones.
One Small Piece of the Bigger Picture
It’s an uncomfortable truth for folks like me who are passionate about trees: sometimes a tree is in the wrong place within the greater city ecosystem.
There’s a lot we can do to preserve trees in the midst of infill and other construction. But we also need to accept that sometimes allowing them to be removed is the right choice for the greater good. Although infill is imperfect and isn’t always easy, it’s what we need to make progress toward a more environmentally and financially sustainable city.
To use the analogy of a forest: a healthy forest isn’t one where no tree ever dies. In a forest, trees sometimes die, but the important thing is that new trees will grow, and that the forest evolves and adapts and renews. It’s the same thing with a city. A city in which individual components like transportation, housing, nature, and neighborhoods can’t evolve isn’t a healthy or sustainable one.
We're living in an age where cities and citizens are being encouraged to plant, plant, plant. While we do need to dramatically increase the canopy cover, we need to be mindful that planting a tree today doesn’t lock us into a lifetime of commitment, precluding us from adapting to our needs in the future.
Emma Durand-Wood likes walkable cities, front porches, street trees, bumping into neighbors, riding her bike, downtowns, and any excuse to check out a new coffee shop, bakery, or shop. A Winnipegger by choice, she lives in Elmwood with her husband and three children. You can connect with her on Twitter @emmaewood.