Recent Posts

  • We Mapped the City’s 311 Requests I wrote this story for Torontoist. To support them, please read the original story on their site. Click to enlarge the map.
    Posted Feb 15, 2017, 5:47 PM by James Steenberg
  • Open Data and Urban Forests - What's Next? The following is a blog post written for the Canadian Geospatial and Open Data Research Partnership (Geothink). The original posting can be found here: ...
    Posted Aug 11, 2016, 5:35 PM by James Steenberg
  • Urban Forests and Big Data James Steenberg     Written for the Ontario Urban Forest Council     Original Posting:     Big data has opened up tremendous opportunities ...
    Posted Jul 7, 2016, 7:48 PM by James Steenberg
  • Global Roundtable - The Nature of Cities The following is my contribution to a Global Roundtable discussion on the Nature of Cities forum. The Roundtables bring together groups of international authors around a central question. The original ...
    Posted Jan 4, 2015, 6:43 PM by James Steenberg
  • Why Do Neighbours Fight Over Trees? Ecology. James Steenberg     Written for the Ontario Urban Forest Council     Original Posting: Sometimes neighbours end up fighting over trees. Sometimes it can ...
    Posted Jul 24, 2014, 6:54 PM by James Steenberg
  • Think ahead! A Century of Urban Forestry Gone Awry James Steenberg & Peter Duinker     Written for the Ontario Urban Forest Council     Original posting:     The Town of Powell River, British Columbia, is ...
    Posted Apr 30, 2014, 5:37 AM by James Steenberg
  • Ask Not What Your Urban Forest Can Do For You James Steenberg    Written for the Science Creative Quarterly    Original Posting:    It’s time that we upped ...
    Posted May 12, 2015, 7:14 PM by James Steenberg
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We Mapped the City’s 311 Requests

posted Feb 15, 2017, 5:38 PM by James Steenberg   [ updated Feb 15, 2017, 5:47 PM ]

I wrote this story for Torontoist. To support them, please read the original story on their site. Click to enlarge the map.

Open Data and Urban Forests - What's Next?

posted Aug 11, 2016, 5:24 PM by James Steenberg   [ updated Aug 11, 2016, 5:35 PM ]

The following is a blog post written for the Canadian Geospatial and Open Data Research Partnership (Geothink). The original posting can be found here:

I recently had the opportunity to go on a Geothink summer exchange at the University of Waterloo hosted by Dr. Peter Johnson, a Geothink co-applicant and Assistant Professor at Waterloo’s Department of Geography and Environmental Management. The main goal of the exchange was to learn about open data and open government from Dr. Johnson with the ultimate goal of writing a collaborative paper on the potential role of open data in municipal urban forestry.

I wrote about my experiences during the exchange in a previous post, and subsequently left Waterloo with an open question on open data – can the open data/open government movement also be embraced in urban forestry? I would like to justify this question with two contrasting tales of cities.


The first tale is about Toronto, more specifically about a neighbourhood in Toronto called Harbord Village where I conducted some of my PhD field research. The neighbourhood and its residents association are quite active in the stewardship of their urban forest. They even undertook a citizen science initiative to inventory and assess all 4,000 of their trees. I re-measured some of their tree inventory in 2014 with the purpose of identifying social and ecological drivers of urban forest vulnerability (e.g., tree mortality). Soon after, my current Geothink supervisor Dr. Pamela Robinson and I began to speculate that a key agent of change was housing renovation. Where we noted incidences of tree mortality, there were often shiny new home additions or driveways where once a tree stood. Fortunately, the City of Toronto’sopen data portal includes building permit data and we were able to test this theory. We did indeed find that building permits (i.e., housing renovation) significantly predicted higher rates of tree mortality.

Municipal urban forestry departments are responsible for planting, maintaining, and removing trees on public land, as well as protecting and sustaining the urban forest resource on public and private land through various policies and regulations. However, it’s important to note that urban forestry is plagued by management challenges due to the limited space and harsh growing conditions of cities. Simply put, trees frequently die when they’re not supposed to – often for unknown reasons – and practitioners are continuously seeking out ways to reduce unnecessary tree mortality. Our findings suggest that urban foresters aren’t talking to urban planners when they should be, or vice versa. Urban planners collect data describing where building renovation occurs. Urban foresters collect data describing where city trees are dying and being removed. Blending these datasets has revealed that better coordination and horizontal data sharing across branches of government might help keep public trees alive. More broadly, these findings indicate an inefficiency in municipal service provision – the provision of the beneficial ecosystem services that public trees provide to city residents. What other urban forest inefficiencies might open data reveal?

The Harbord Village tree inventory and corresponding volunteered geographic information (VGI)


The second tale is about Edmonton and paints a different picture. I stumbled across one of Edmonton’s approaches to urban forestry during my summer exchange while learning about the various open data programs across Canada. Their urban forestry branch has used Open Tree Map – a web-based application for participatory tree mapping – in their yegTreeMapproject so that “individuals, community groups, and government can collaboratively create an accurate and informative inventory of the trees in their communities”. In short, citizens in Edmonton that feel the urge to participate in municipal urban forestry can do so by downloading tree inventory data, using the data to their heart’s content (e.g., community-based stewardship programs), and entering new data into the City’s database.

This approach to what I’ve started calling ‘open urban forestry’ could conceivably improve citizen engagement with municipal government and its urban forestry programs. Much of the urban forest resource is situated on private residential property that the city doesn’t have direct access to, so citizen engagement in stewardship activities is a key piece of the puzzle. Moreover, urban tree inventories are notoriously fickle when it comes to data, being both expensive to generate and quick to become out-of-date and obsolete. Crowdsourcing a city’s tree inventory could conceivably provide better data to support decision-making in urban forestry, such as where to plant trees, what species to plant, and where trees are in decline or hazardous.

Edmonton’s yegTreeMap user interface on Open Tree Map

I have been very fortunate to be able to incubate these ideas with guidance from Dr. Robinson and her knowledge of urban planning and citizen engagement. Moreover, it was because of my Geothink summer exchange with Dr. Johnson at the University of Waterloo and his knowledge of open data and open government that I arrived at my current line of thinking on the benefits of open data and crowdsourcing for urban forestry. My next steps forward will be to think critically about these ideas as well. What are the environmental justice implications around who gets to participate in open urban forestry? Crowdsourcing tree inventories through open data programs may provide better data, but do they simultaneously justify the under-funding of municipal urban forestry programs? I’m excited to develop these collaborative ideas over the coming weeks and to hopefully answer my open question on open data.

Urban Forests and Big Data

posted Apr 2, 2015, 6:59 PM by James Steenberg   [ updated Jul 7, 2016, 7:48 PM ]

James Steenberg     

Written for the Ontario Urban Forest Council     

Original Posting:     

Big data has opened up tremendous opportunities for understanding our urban forests. Big data is a pretty loose term, but for the most part it refers to massive sets of data that owe their existence to the internet. More specifically, the easy ability to collect, store, and share data about everything and everyone doing anything. So how could this possible help our understanding of urban forests? From the simplest perspective, we now have a comparatively quick and cheap way to view our urban forests as tree canopy cover across an entire city using satellite data. Using this information, cities then set future canopy targets in their official plans and policies. For example, Toronto has adopted the lofty target of increasing its canopy cover from 28% to 40% in the next half century.

But what big data has really exposed is that, by and large, the ecology of the urban forest might be as much, or even more, influenced by people as it is by nature. This is because big data allows us to predict things where prediction usually is not possible. Across a single city – again using Toronto as an example – we can see and analyze the distribution of income, education, crime, ethnicity, and trees at the same time. Groundbreaking studies have since shown that trees are associated with higher income, lower crime rates, and better human health. We’ve also seen that city neighbourhoods are de facto ecosystems in the urban forest. Research has even shown who is more likely to plant a tree.

The next question is why does all this matter? From a philosophical point of view, it’s nice to know what makes the urban forest tick. But from a management point of view, mixing tree data with people data is incredibly valuable for taking care of the urban forest responsibly. Knowing the current relationship between people and trees in the city (i.e. more money = more trees) can help to illuminate what we want that relationship to eventually look like (i.e. trees for everyone!). In other words, we can begin with questions like who is likely to plant a tree and move to more important questions like who is likely to need a tree.

Global Roundtable - The Nature of Cities

posted Dec 5, 2014, 10:13 AM by James Steenberg   [ updated Jan 4, 2015, 6:43 PM ]

The following is my contribution to a Global Roundtable discussion on the Nature of Cities forum. The Roundtables bring together groups of international authors around a central question. The original posting, and contributions by the 11 other authors can be found here:

How can different ways of knowing—and of producing knowledge—be useful for understanding and managing urban ecosystems?

My current work has me reflecting on models – ecosystem models, that is – and their role in understanding nature in the city. From my viewpoint, anytime an environment, or a system, or a concept, is described in anything but its entirety it becomes a model. This could be through narrative, spatial representation, or ecosystem modelling.

As both researchers and practitioners of and/or in urban ecosystems, we often undertake some form of assumption, abstraction, and aggregation of the real world. We construct a model and therefore omit knowledge. Arguably, the hope is that what has been left behind, whether for the sake of parsimony, practicality, or functionality, does not compromise the model’s utility in describing the ecosystem. This hope is then dependent on what is defined as an ecosystem.

Theoretical discussions on the ecosystem concept no longer view ecosystems as deterministic, stable, or within closed boundaries. They are adaptive, and both scale and context dependent. Importantly, current urban ecological theory now envisions human activities as internal processes that shape ecosystem structure and function, rather than external agents of change and disturbance.

In my own research, I have been attempting to bring this modern urban ecosystem concept from the theoretical to the applied realm. I’m developing a framework for identifying and classifying urban forest ecosystems using quantifiable and spatially explicit variables that represent (i.e., model) their biophysical landscape, built environment, and human population. Ecosystem classification is a form of modelling that attempts to answer the following questions for researchers and practitioners: What does an ecosystem look like? What happened to make it look that way? What will it look like in the future? In such a fashion can they hope to intervene and manage urban ecosystems towards a more desirable state.

However, in the process of ecosystem classification we knowingly ascribe categorical characteristics to continuous phenomena and draw sharp edges around soft boundaries. This latter issue has been long recognized as a caveat of classifying landscapes – as ecosystems or otherwise. Yet, ecosystem classification has still been recognized as a useful tool for modelling and managing complex systems in its hinterland applications where the emphasis is primarily on biophysical ecosystem components.

In the urban landscape, where the influence of densely-settled human populations and their social structures and institutions on ecosystem processes are so evident, can ecosystem classification still maintain its utility? Can it be adapted to account for these theoretical advancements in urban ecology and the ecosystem concept?

These are my research questions, though I will admit to feeling apprehensive in shifting from the theoretical to the applied. Specifically, the quantification and classification of the ‘human component’ of urban ecosystems is fraught with challenges. For example, ecosystem classification is, in part, a statistical endeavour. As illustrated above, people at that tail end of that distribution curve who occupy the space outside two standard deviations will be the most dissimilar ecosystem components. In urban forest management, this population may be at risk of marginalization – or perhaps equally likely, may be a disproportionally vocal and influential subset of the population and ecosystem. In the context of building ecosystem models, is the omission of social knowledge as acceptable as that of ecological knowledge?

As a researcher, I’m as fascinated by the flaws of ecosystem classification as I am by the possible applications. I do think that applying ecosystem classification in strategic urban forest planning and management can be a valuable way of knowing and of producing knowledge about these ecosystems. Rather, I think this dialogue is the result of examining social processes from my own physical sciences perspective, and thus emphasizing the absolute necessity of inter- and transdisciplinarity within the research and management of urban ecosystems.

Why Do Neighbours Fight Over Trees? Ecology.

posted Jul 24, 2014, 6:45 PM by James Steenberg   [ updated Jul 24, 2014, 6:54 PM ]

James Steenberg     

Written for the Ontario Urban Forest Council     

Original Posting: 

ginkgoSometimes neighbours end up fighting over trees. Sometimes it can get ugly.  In fact, a recent legal battle over a maple tree in Toronto attracted attention from both national media outlets and one of the country’s more prominent defense attorneys.  With all the widely known benefits that homeowners derive from trees, it does seem surprising that such arguments would arise. It turns out that lawnmowers and urban ecology are to blame for all this strife.


To explore the issue, let’s take a stroll in my own neighbourhood of Cabbagetown in Toronto.  It’s a typical older, residential neighbourhood with your garden variety maples growing pleasantly along the street sides. Many manicured front lawns even daunt especially eye-catching tulip magnolias, flowering dogwoods, and ginkgo trees that are tended with care by local residents.


But a walk down the neighbourhood’s laneways and alleys will afford you a view of a different urban forest, made up of countless wild-looking trees precariously growing beside and through backyard fences.  This rugged lot is composed of Manitoba maples, Siberian elms, and tree of heaven, among others – all fast-growing, pioneer species that tolerate and even thrive in forgotten or degraded urban sites.


Trees like these that were brought into Ontario cities from afar do an incredible job at growing wherever there is room, whether they are wanted or not. In particular, backyard fencelines that are missed by the lawnmower provide some of the most ample habitat in cities. When these trees grow up, they bulge through fences and across property lines.


fenceThe benefits of having a tree on your property span across ownership boundaries, but so do the costs.  All too often neighbours disagree on whether these costs outweigh the benefits. What’s more, that Toronto legal battle over the maple set the precedent that these trees belong to both neighbours, and approval from both is needed to legally prune them or cut them down.

These shared trees – loved and hated – are the trees that neighbours fight over.  But for better or worse, a sizeable portion of a given city’s urban forest and the ecosystem services it delivers is made up of these accidental, misunderstood, often contentious trees.


James Steenberg

Ontario Urban Forest Council


Think ahead! A Century of Urban Forestry Gone Awry

posted Apr 30, 2014, 5:35 AM by James Steenberg   [ updated Apr 30, 2014, 5:37 AM ]

James Steenberg & Peter Duinker     
Written for the Ontario Urban Forest Council     
Original posting:     

The Town of Powell River, British Columbia, is a great example of how not to do urban forestry.

If you’ve heard of this quiet and rural coastal community, you will certainly be perplexed by our choice of topic and example. After all, it’s in BC and we’re in Ontario and Nova Scotia. But the Town provides such a potent and visually striking microcosm of a century of unplanned urban forestry that this had to be written.

Powell River is a divided and small town dotting BC’s rugged Sunshine Coast. The north end of the town is called Townsite. Townsite is a planned community, built a hundred years ago for the workers of the paper mill, and it’s a National Historic Site of Canada. The architecture is quite stunning, with some stately manors boasting mighty copper beech trees in the yard – testimony of the Victorian influence on our early days of urban forestry.

This small mill town, surrounded in the countryside by mighty red cedars, Douglas firs, sitka spruces, and other coastal rainforest giants, would certainly seem to be free of the urban forestry challenges that face Canada’s metropolises. And yet, even without the harsh environments of major cities, urban forestry can still go wrong without shrewd foresight.

Two of the main residential streets in Townsite are Oak Street and Poplar Street; streets in the community were obviously named after the species that were initially planted when the town was built a century ago. Today, Oak Street is fully shaded by majestic and long-lived red oaks over a metre in diameter; it’s a street any lover of the urban forest would be happy to call home.

In contrast, Poplar Street, whose namesake is a much shorter-lived tree species, is barren and lined only by parked cars. The experience of walking down each of these adjacent streets is strikingly different. However, in a matter of some decades, Oak Street will look just like Poplar Street, since all those lovely oaks are of the same age and longevity.

Thus, it behooves us to think long past initial street-tree establishment to the conditions of the urban canopy at least a half-century – perhaps more – forward. We must not let the present beauty lead to complacency. In other words, after planting the trees, we must not take them for granted. Trees of some species live a long time, and of others they do not. A diversity of tree species and ages – planted and tended consistently over the years – will ensure a robust urban forest and constancy in the benefits we derive from trees in towns and cities.

Unless you want to experience the dizzying highs and lows of urban forest splendour evident on Oak and Poplar Streets in Powell River, think one hundred years ahead, and think diversity.

Ask Not What Your Urban Forest Can Do For You

posted Apr 2, 2014, 6:53 PM by James Steenberg   [ updated May 12, 2015, 7:14 PM ]

James Steenberg    
Written for the Science Creative Quarterly    

It’s time that we upped the ante on the level of public discussion on the urban forest. What is the urban forest you ask? Well it’s those pleasant remnant stands of forest that speckle the urban landscape, like Vancouver’s Stanley Park – but it’s also every other tree in the city, from that old oak tree on the front lawn to those pitiable and short-lived trees sprouting from the concrete downtown. Trees have been the recipient of a growing urban celebrity over the past years. I subscribe to Google News alerts, so whenever the words “urban forest” appear in a news article, I get an update. As these alerts were chiming away in my inbox in increasing abundance, I noticed that a solid 90% of the headlines were all hailing the benefits of trees for the city dweller. And I thought to myself, the other half of the story is missing.

First – why all the fuss? A lot of this celebrity can be attributed to the growing attention given to the urban forest by academic researchers. City forests, with all their idiosyncrasies, are attracting more and more researchers, who in turn are discovering more and more benefits of having trees in cities. An early example of this was the “View through a Window” [1] study, which showed that hospital patients with a window view of trees and natural settings recovered faster from surgery. Since then, research has uncovered a slew of other benefits selflessly provided by urban trees, from reducing crime rates in Baltimore [2] to increasing the value of homes in Finland [3].

The next critical point in the urban forest timeline came with the development of a computer model. The United States Forest Service created the i-Tree [4] model (suite of models, actually), which synthesizes scientific research into an off-the-shelf piece of free software that can be used by non-experts – usually city staff or community groups – to inventory their urban trees and actually put numbers and dollar figures to their value. Toronto recently conducted an analysis of its urban forest using i-Tree in 2008 [5], and found that the bare-bones replacement value of the urban forest is a whopping seven billion dollars. Moreover, they provide Torontonians with sixty million dollars in ecosystem services.

There are also some more esoteric benefits from trees that are steeped in the the social sciences. Trees provide place attachment and a sense of identity for people to their streets, parks, neighbourhoods, and city [6]. In Japan, people partake in Shinrin-yoku (literally, forest bathing), where they immerse themselves in the woods to reap the spiritual benefits [7]. Even though they cannot be as easily affixed with a dollar value in computer models, these psychological benefits that arguably all city residents experience, knowingly or not, are really where the rubber hits to road in terms of ecosystem services.

Amazing, right? Absolutely. So how can we blame the media for the fluffy and abundant coverage of city trees of late?

We can’t. But ending the narrative at this point paints an incredibly unbalanced picture of trees in the city. To the passerby it seems as though we have always had trees in the city, and just recently science came along and told us that they’re tops. Urban trees and the urban forest ecosystem, however, are far more complex (and frankly a little gloomier) than the happy-go-lucky altruists we are making them out to be.

City trees are actually subject to an appalling amount of stress, disregard, injustice, and blatant abuse. First off, the urban natural environment in general is degraded – without question – because we live in it and build things and pave surfaces and throw stuff out in it. We plant plants that shouldn’t be there, which become invasive. We introduce nasty critters and blights like the Dutch elm disease, Asian longhorn beetle, and most recently the emerald ash borer. We plant trees in compacted and degraded soils or tiny little concrete planters known by arborists as tree coffins. We chop off their limbs in a brutish manner to accommodate our utility lines. We gash their boles with lawnmowers, snowplows, and bicycle locks. We even vandalize trees! It’s just a hard-up life for John Q. Maple and Joe the Plumb Tree, trying to carve out a little piece of soil to call their own, make a living at providing us with ecosystem services, and raise a family of seeds.

All of these issues that face urban trees, and urban ecosystems in general, lead to a somewhat counterintuitive conclusion: the urban forest needs us. Unlike the tried, tested, and true forms of conservation in the hinterland where we can simply leave nature alone and it will mend itself of our transgressions, the urban forest ecosystem demands a new type of conservation; a new type of management. A seminal journal publication on urban forestry stated clearly that “sustainable urban forests require human intervention” [8]. So what does this mean? Let’s examine.

Enter Toronto, my hometown and the biggest city in Canada. Take a stroll for a moment along the Lower Don River trails; down the stairs at the pedestrian bridge in Riverdale Park and into one of Toronto’s key green features. The stately silver maples and graceful magnolias that lined your walk through the Victorian neighbourhood of Cabbagetown to arrive here are transformed abruptly into a dark and tangled wood, with ragged stands of gnarly old willows and bulging Manitoba maples, dripping with equal parts of invasive Virginia creeper and torn-up plastic bags.

Another key feature along the trail is a dense canopy of Ailanthus altissima, known somewhat ironically as the tree of heaven. This tree is also referred to as “Ghetto Palm” [9] because of its prevalence in unmanaged – and frequently poor – urban neighbourhoods. Before your arrival in Caggabetown, walk through some contrasting high-density neighbourhoods and look along building foundations, fencelines, and alleyway potholes and you will see the tree of heaven growing from mere cracks in the asphalt.

This species originally calls from China, and was brought first to Europe then to North America as an alluring ornamental wrought in the mysteries of the Orient. Its insatiable capacity for growth earned it the title tree of heaven, since it grew with such vigour towards the skies. This made it an ideal candidate for the harsh urban environment, where it showed utter disdain for the aforementioned assaults on city trees, and indeed flourished. However, the tree’s vigour soon became a problem. Its amazing capacity for growth meant that it could establish within naturalized, unmanaged forest ecosystems, like the Don Valley, and outcompete the region’s native tree species with ease. Moreover, the tree is allelopathic, meaning that it produces biochemicals that stop other (i.e., native) species from growing anywhere near it. The tree of heaven may be the poster child of urban forests without intervention.

Go a little farther north along the Don trail, underneath the majesty of the Bloor Viaduct, and you enter a sunny meadow. But in this seemingly appealing meadow can be found an unnavigable bramble of some of Ontario’s most notorious invasive plants: Japanese knotweed, garlic mustard, and endless fields of dog-strangling vine. Perhaps not coincidentally, this ecologically-marginalized meadow is also home to some of the City’s socially-marginalized populations that inhabit camps just beyond the treeline.

Please don’t misinterpret me. These Lower Don trails are my favourite spot in the City precisely because, among many other benefits, they are so fascinating for the urban ecologist. And to be fair, incredible work on ecological restoration and management is indeed already in progress in the Don River Watershed at the hands of the Toronto and Region Conservation Authority [10]. What the Don does in the context of this story is provide a case and point that urban trees and forests are incredibly vulnerable, and left to their own devices to grow in the city will likely suffer. They demand varying approaches to management – human intervention.

The form of that human intervention is critical, however. There exist hidden vulnerabilities of the urban forest. These vulnerabilities are dangerous because of their relative invisibility, but perhaps even more so because they can manifest while we are trying to helpthe urban forest. In response to the aforementioned stream of news stories about the benefits of trees (which, to be fair are legitimately amazing), a natural reaction is to plant even more trees. But what would happen if all those planted trees were the same species? It would make the urban forest highly vulnerable to both existing and yet-to-be-introduced insects and diseases that eat and kill trees. These forest pests often target one species or one genus, so when the urban forest is composed largely of those species and genera, we lose them all at once! The most notable disaster of this kind was in the mid-1900s, when North American cities often planted nothing but elm trees along streets. Then the Dutch elm disease arrived, and it transformed these green-canopied, sun-dappled boulevards into barren and exposed tree-less streets. The unexpected horror that was felt by society in this instantaneous loss of their trees helped to birth the concept and practice of urban forestry in North America [11].

Now, what would happen if we planted all those trees in just one happy summer, and we planted so many trees that we didn’t need to plant more for a hundred years? Well, when all of those trees simultaneously enter their winter years and eventually succumb to the ravages of time, we again lose them all at once! Moreover, forests and urban forests alike are far more susceptible to falling over in storms with an over-abundance of old trees of the same age. And we will certainly be seeing a lot more storms in the coming decades. This latter scenario happens more frequently than logic would dictate. Everyone loves scotch. But imagine if distilleries only waited to start the next batch of twelve-year old single malt when the last batch ran out? That would be a pretty bleak eleven years.

As you are starting to guess, managing an urban forest is hard. Because of the long life of trees, the urban forest ecosystem, like all forests, is shaped by very slow processes, so management must have considerable foresight to avoid potentially delayed and disastrous effects. Management also needs to be intensive and continuous to combat all those tree injustices we talked about earlier.

Management needs to be inclusive – often over half of a city’s urban forest is situated on private residential property and subject to the whims of the homeowner, for better or for worse. This also means that city foresters can’t get their hands a notable chunk of the trees in their jurisdiction. Consequently, municipal governments can’t be expected to shoulder the whole burden of management. Outreach, educational material, by-laws, and incentive programs to engage homeowners and businesses in urban forest management are a must.

The complex ownership regimes of cities really put a stick in the spokes of sustainable management of the urban forest too. In those endless swaths of Canadian boreal forest that we typically associate with forestry, a single forest products company will manage hundreds of thousands of hectares of Crown forest. In the city, a single hectare of urban forest might be under the management (or mismanagement) of dozens of homeowners, small business, institutions, random pedestrians, and city arborists and foresters, all with differing values and objectives. This is complicated even further by the fact that the product being harvested is not timber, but psychological benefits and other such intangible amenities that care little for property boundaries. Lastly, urban forest management needs to transcend the various socio-political quandaries that we create in cities, like policy gaps and a lack of enforcement, development pressure and densification, insufficient municipal urban forestry budgets, and a flat-out lack of awareness.

These are my concerns, if we tell just one side of the story.

So remember, the next time you take a leisurely stroll through your neighbourhood, enjoy the view of the park out of your office window, dabble in some Shinrin-yoku, or enjoy any number of the ecosystem services city trees provide, please be sure to ask whatyou can do for your urban forest, because it needs you.


1. Ulrich, R. S. (1984). View through a window may influence recovery from surgery. Science, 224, 420-421.

2. Troy, A., Grove, J. M., & O’Neil-Dunne, J. (2012). The relationship between tree canopy and crime rates across an urban-rural gradient in the greater Baltimore region. Landscape and Urban Planning, 106, 262-270.

3. Tyrväinen, L. (2000). Property prices and urban forest amenities. Journal of Environmental Economics and Management, 39, 205-223.


5. City of Toronto. (2008). Every tree counts: A portrait of Toronto’s urban forest. Retrieved from

6. Jones, O., & Cloke, P. (2002). Tree cultures: The place of trees and trees in their place. London, UK: Berg.


8. Clark, J. R., Matheny, N. P., Cross, G., & Wake, V. (1997). A model of urban forest sustainability. Journal of Arboriculture, 23, 17-30.

9. Burkholder, S. (2012). The new ecology of vacancy: Rethinking land use in shrinking cities. Sustainability, 4, 1154-1172.

10. Toronto and Region Conservation Authority. (2009). Don River watershed plan: Beyond forty steps. Retrieved from–

11. Jorgensen, E. (1986). Urban forestry in the rearview mirror. Arboriculture Journal, 10, 177-190.

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