Prepared by the Definition Sub-Group of the Urban Canopy Committee of the CSLA
Importance of the Urban Forest
The importance of the urban forest is widely recognized in measures of ecological and public health and resiliency to climate change. The urban forest provides biological and ecological habitat and diversity, stormwater mitigation and the resulting stormwater quantity and quality benefits. It also reduces the urban heat island effect and contributes to the passive heating and cooling of buildings, provides solar/UV protection, and demonstrably lowers ambient air temperatures, reduces air pollution, sequesters carbon, and provides aesthetic and myriad public health benefits to the community.
These benefits of the urban forest contribute to an improved quality of life for everyone in urban areas. As almost 95% of Canadians live in urban or suburban areas, the urban forest has incredible impacts on the majority of Canadian’s physical, mental, and ecological health and well-being.
Importance of the Urban Tree Canopy
Urban forest professionals have long advocated for the consideration of the Urban Forest as a green infrastructure asset, albeit of a different nature from traditional infrastructure assets. Traditional asset management includes features that can be easily measured, have defined life-cycles and associated costs, and can be planned for in capital forecasts. In quantifying the benefits of the urban forest (as with ecosystem services analysis, and mapping canopy coverage, etc.), infrastructure asset management can now include the urban forest – providing infrastructure legitimacy in planning for and assigning capital funding to the asset. Asset management legislation at the provincial level in many provinces now requires consideration and planning for green infrastructure assets.
The terms “Tree Canopy” or “Canopy Cover” have been utilized and are broadly accepted as an easily measurable and quantifiable metric to establish baselines and goals to increase and maintain/support the health of the Urban Forest and the benefits that it provides.
Urban tree canopy analyses can provide unique information about the urban forest, such as relative urban forest age and condition of trees by location, species diversity, micro-climate impacts, and may even reveal inequitable distribution of the urban forest across socio-economic communities. It is an excellent tool for planning – but only one needed out of many to ensure a continuously healthy and growing urban forest.
Defining the Urban Tree Canopy
The task for the Definition Sub-committee was to clearly define “Urban Tree Canopy” to provide a more focused definition of ‘Urban Forest’ and ‘Canopy’ to support the CSLA membership’s endeavors to lend professional support and advocacy to the ongoing health and sustainable growth of the urban forest in general.
After much consideration and discussion within the sub-committee, we have landed on the following definition.
This definition is a synthesis of existing definitions of “Urban Forest” from the Canadian Urban Forest Strategy (CUFS), and broadly accepted definitions of “Urban Forest” and “Urban Tree Canopy” from the US Department of Agriculture Forest Service. We recognize the years of research and experience in Urban Forest management by municipal and private arborists, urban foresters, urban ecologists and biologists, landscape architects, and other professionals which has led to the creation of these definitions. We have combined these existing definitions in a way that we believe supports the many ways in which the CSLA’s membership can impact the urban forest across Canada.
This definition does not specifically address:
- The Urban Forest – sum of the whole, of which the urban canopy is an important part;
- Urban Forest health – as a whole, or as individual trees;
- Different types of urban forest – I.e. natural heritage areas vs parks/open space vs a spectrum of urban spaces, from sprawling traditional suburban to the densely urban and every density in between.
- Other critical parts of the urban forest, such as soil integrity and other non-canopy plants/plantings (including sod, perennials and grasses, or shrubs), etc; and
- Excludes rural/agricultural areas, protected natural areas (unless encompassed within urban settlement areas) and wilderness areas.
How this Definition Serves CSLA Membership
Quantifying the urban forest by Canopy cover can be particularly useful when discussing or advocating for the urban forest with professionals who are not other landscape architects or urban forest professionals, including:
- Professional planners;
- Asset managers;
- Civil engineers;
- Politicians; and
- The general public.
Quantifiable goals and targets for canopy cover allow for preliminary assessment and re-assessment of the size and anticipated benefits of the urban forest in a way which can drive progress forward in a fiscal and numerical language that decision makers and supporters understand.
As landscape architects, we have the professional opportunity to advocate for the protection of trees impacted by development and to support the growth of the urban forest at the municipal level by contributing to land use planning, policy creation, bylaw creation and enforcement, and capital and operational budget planning.
Landscape architects are also uniquely positioned and can be directly responsible for influencing or reducing direct impacts to existing trees from private or public/municipal development, and are responsible for a majority of planning/designing for the growth of the urban forest through master plans, concept plans, site plans, tree preservation plans, planting plans, streetscape plans, and by being contributing stakeholders on civil engineering/grading and drainage plans.
Supporting the Work of Other Sub-Groups
In the recent CSLA Urban Tree Canopy survey, respondents indicated:
Landscape architects should be advocating for the urban canopy to the government (96%), to related professions (80%), and to the general public (71%).
Partners were identified as Urban foresters (80%) and Public Works (88%)
Top Priorities are protecting the existing urban canopy (72%), planting more resilient urban canopy (64%) and increasing the size of the urban canopy (57%).
Biggest threat was overwhelmingly identified as development (80%)
In order to better support both advocacy and responsibility of the urban forest canopy, the work of the other sub-groups will cover Policy (through a white paper); Standards and Bylaws; and Regionally specific tree lists.