The Case for Trees in Urban Design: 5 Tools to Support Better Planning

By Eva Adler, Geospatial Information Specialist at the United States Agency for International Development (USAID), Washington DC.

Trees present an excellent opportunity for planners to help enhance urban mental health and wellbeing. But choosing the wrong trees can be more detrimental to urban communities than having none at all. To make the most of urban green spaces, both tree characteristics and spatial thinking need be considered early on in the planning process. In this article, we will explore common challenges in choosing trees in urban design and how five tools can better support planning and build more vibrant, healthy urban communities.

The ‘wrong trees’ can do more harm than good

These tools are important because despite the best of intentions, implementation problems often occur at the neighborhood scale when the ‘wrong trees’,  or trees unsuitable for a place’s specific urban variables, are brought into the built environment. For example, city planners plant beautiful Ginko bilboa trees along local roads to contribute to the city’s beautification project. The intention is to increase shade, safety, health and happiness across the local community - all laudable aims. However, over time the trees grow too large for the city’s infrastructure and budget. The branches begin to destroy electrical lines, crack underground water pipes, fall onto cars during winter storms, and litter pounds of smelly fruit every spring. The city  becomes frustrated and cut down the trees... only to replace them with smaller, younger Ginko trees. So where did they go wrong?

How to choose the ‘right tree’ for mental health, wellbeing… and for tax dollars

In the US, the Arbor Day Foundation advocates The Right Tree in the Right Place framework, emphasizing that proper planning is vital to achieve the outcome of healthy urban green spaces. They describe trees that will “cool your home in summer and tame the winter winds… grow well in the soil and moisture of your neighborhood… be properly placed to avoid collisions with powerlines and buildings.” Furthermore, thousands of city tax dollars can be prevented in sidewalk and electrical repairs if planners match trees to the urban locations in which they will be planted.

Tree characteristics to consider for sustainable urban design:

• Height, canopy spread, form, and shape
• Growth rate
• Soil, sun, and moisture
• Fruit
• Temperature extremes in your region - hardiness zone
• Urban variables (soil compact, road salt, contained space, toxicity to pets, etc.)
  

Organizations like Casey Trees strive to prevent planning issues associated with tree planting and restore the urban forest of the Washington DC through education and outreach, policy advocacy, and private and public partnerships. Source: Casey Trees website

Tool 1: Tree Finder Wizard (for the US)

But how to identify the right tree for a particular location? For instance, a local coffee shop in New York City wants to plant a few trees above the front patio to give customers shade. But there are electrical lines 50 feet above ground, there’s limited planting space for roots, partial shade, and the northeast winters are harsh. So what should they do?

One helpful tool they can use is the Tree Finder Wizard tool, developed by the American Arbor Day Foundation. This tool identifies the right tree species for any community in the US based on the variables of zip-code, soil, height, growth rate, spread, and aesthetics desired (fruit, evergreen, deciduous, etc.) | website

Source: Arbor Day Foundation, website

Tool 2: National Tree Benefit Calculator (for the US)

The Right Tree Right Place framework is an important first step towards using trees to help achieve healthier communities and more impactful outcomes. However, getting the information and facts to the right people is another challenge. Evidence of economic improvement can form a persuasive argument that helps turn ideas into action. Whether it’s city officials, policy makers, neighborhood HOAs, or school principals who need to be persuaded, the free National Tree Benefit Calculator is an effective tool to communicate specific economic benefits of urban trees and diversity of tree populations. While it does not yet consider health benefits, it calculates the monetary benefit of trees based on tree species, age, and size based on potential improvements in stormwater, property value, energy usage, and air quality |  website

Source: Arbor Day Foundation, website

Tool 3: Google’s SketchUp

However, city planning doesn’t only mean city effort. Local non-profits, businesses, and homeowners can too create designs for public spaces, backyards, and community gardens using the right tree right place framework and free 3D spatial design tools.

SketchUp is Google's free design software. It incorporates a few landscape templates to help get a project started. In SketchUp, one can upload a photo and create objects from scratch easily on a laptop to help plan tree design within a given landscape. | website

Sources: SketchUp, website | Bēhance City Architecture, website

Tool 4: Garden Visualizer

The Marshalls Garden Visualizer lets a beginner user design a garden or small public space with stunning 3D quality. Photos of community structures and buildings can also be uploaded and displayed in the backdrop | website

Sources: The Self Sufficient Living Blog, website | Landscaping Visualizer, website

Tool 5: Mappler K2

Predicting future trends and integrating community input early on into the design process are challenges that city and regional planners encounter regularly. Where do community members want more trees? In what areas do we need more trees to improve safety, mental health, and healing? How can a city streamline input and provide effective solutions? Mappler is a free crowdsource mapping tool and a mobile data collector app to easily conduct assessments and identify community needs across a city scale. It is a tried and true tool to collect diverse inputs on a large scale to help identify community issues, needs, and successes. | website | community asset mapping

Asset Mapping using Mappler, website |

A prime example of the use of Mappler was in New Jersey where local residents entered the location of road potholes. Local officials then used this input to prioritize areas of operation and improve road conditions. When each road was fixed, they were able to input a comment to notify the public that the issue they identified had been fixed.

Source: Mappler Mobile, website

This same process can be used for identifying other community needs, for instance the tracking and maintaining of urban forests as demonstrated by Casey Trees in Washington DC (online map).

These tools can contribute to smarter urban planning that will achieve the wide range of positive impacts - and help avoid the unintended pitfalls - of planting trees to improve community life.

Do you have a great tool to suggest? Please add a link and description in the comments section.

About the Author

Eva Adler is a passionate advocate for green spaces as it relates to public health, social equity, and GIS. She uses maps to ask deeper questions and uncover hidden truths. She is a Geospatial Information Specialist at the United States Agency for International Development (USAID) in Washington, DC. Prior to her current role, she facilitated a Mapping for Social Good online course, collected geospatial data across a 50-acre botanical garden, and conducted community health surveys in Nepal. Ms. Adler studied at the University of Colorado at Boulder in Ecology and Geography, with plenty of time to enjoy her outdoor hobbies. In her free time she hikes, rock climbs, makes jewelry, and explores new places.