Episode 51: Urban Greening with Sandra Albro (Holden Forests & Gardens)

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Episode Intro Notes

What We Will Cover

• What is urban greening?

• How common is urban green space generally?

• Why is urban greening important?

• Urban greening on vacant land / introduce Vacant to Vibrant

• What are the success factors and challenges for urban greening initiatives?

• How can you promote urban greening into your neighborhood?

• About Island Press and Sandra Albro

What is urban greening?

The term urban greening, also called green infrastructure, refers to public landscaping and urban forestry projects that create mutually beneficial relationships between city dwellers and their environments. 

The most common forms of urban greening are installing trees, parks, and landscaped green areas, oftentimes in newly-built urban areas. However, not all urban greening happens in new developments; there are plenty of examples of urban greening retrofits where older urban infrastructure has been revitalized with a green thumb. 

One of the most famous examples of this is New York City’s High Line Park. The High Line was originally built as an elevated rail line that carried trains through the West Side of New York City in the early 1930s. As train use dwindled from the 1960s to the 1980s, the structure fell into disrepair and sat idle for decades. Then, in the early 2000s, chatter began about how to capitalize on the park as an urban green space. Today, after years of effort, the High Line is a 1.5 mile greenway featuring 500+ species of plants and trees and hosts thousands of visitors each year.

How common is urban green space in the first place?

The goal of urban greening is to create functional green space for city dwellers. Some cities have done a better job of incorporating green space within their boundaries than others. To contextualize this, let’s start by expressing parks and gardens as a percentage of total land area. Looking globally, major world cities with the highest percentages of public green space include:

• Moscow (54%)

• Singapore (47%)

• and Sydney (46%)

Cities with the smallest percentages include:

• Shanghai (2.8%)

• Istanbul (2.2%)

• and Dubai (2%)

Here in the US, New York has the highest percentage at 27%. On the other end of the spectrum we have Los Angeles with 6.7%. Austin is situated right between them with 15% of total land area dedicated to public green space.

Another way to quantify how much urban green space a city offers its inhabitants is on a per-capita basis. Let's zoom into the US specifically. Think you can name the top 5?

1. Minneapolis (2.43 acres per capita)

2. Kansas City (2.13 acres per capita)

3. Cincinnati (1.6 acres per capita)

4. Washington DC (1.4 acres per capita)

5. Nashville (1.3 acres per capita)

Now, those stats are one thing, but just because a city has a lot of green space doesn’t mean that green space is equally accessible to all of a city’s inhabitants. In fact, a recent University of British Columbia study revealed that access to green space reflects broader class and racial divides. Residents with higher levels of education and higher incomes are more likely to have access to green space, while minority residents are less likely to have similar access to green space in large, dense urban areas.

Because the distribution of green space often disproportionately benefits predominantly white and more affluent communities, access to green space is increasingly recognized as an environmental justice issue. This makes the aim of the Vacant to Vibrant project so pressing, which we’ll explore in more detail in a bit.

Why is urban greening (and green space) important?

Let’s start on the human health side. A growing body of evidence shows a relationship between amounts of neighborhood green space and people’s health and well-being. Specifically, access to green space can promote physiological effects such as lower concentrations of cortisol (your body’s main stress hormone), lower pulse rate and blood pressure, and healthier nerve activity. Proximity to parks has also been associated with greater frequency of physical activity, reduced weight, and lower coronary heart disease. 

On the flip side, lower exposure to green space has been associated with a number of lifestyle diseases such as obesity, Type II diabetes, osteoporosis and stress-related illnesses such as depression, heart diseases and mental fatigue.

And the benefits aren’t just physical: a number of studies link exposure to green space with mental health benefits like improved mood, self-esteem, reduced stress, reduced cognitive fatigue, and greater attention capacity. In fact, one study in Philadelphia found that in neighborhoods below the poverty line, greening interventions on vacant lots decreased residents’ feelings of depression by more than 68%. 

Here’s one more impressive example to underscore the benefits of urban green space. One study based in Toronto that analyzed densities of trees throughout the city as a metric for green space found that having 10 more trees in a city block, on average, improves health perception - a subjective self-rating that has been proven to be a strong predictor of actual health status - in ways comparable to an increase in annual personal income of $10,000 or being 7 years younger.

Basically, access to green space is so healthy that we might as well call it a vitamin to add to your diet. And actually, one of Scott’s favorite authors, Richard Louv, wrote a whole book on Vitamin N--nature!

Beyond human health, urban green spaces also carry larger environmental benefits.

1. First, these green spaces mitigate the effects of the urban heat island effect. As a refresher, the term urban heat island refers to the phenomenon where a metropolitan area is significantly warmer than the rural areas surrounding it. The heat island is driven by the density of buildings, the absorption of light by those buildings, and the relative lack of vegetation in cities. Get this: release of heat absorbed during the day by asphalt and densely packed buildings can make the downtown area some 20 degrees warmer in some cities. Adding more green spaces to a city helps offset these higher temperature.  A mature tree canopy reduces air temperatures by about 5-10 degrees Fahrenheit.

2. Second, the trees found in urban green spaces do wonders for our air quality. Here’s another potential party fact: two medium-sized healthy trees can supply the oxygen required for a single person over the course of a year. Beyond producing oxygen, trees also capture airborne particles like dirt, dust, and soot - a mature tree absorbs between 120 to 240 lbs of the small particles and gases that comprise air pollution.

3. Additionally, urban green space helps regulate the flow of water through a city’s watershed. These green spaces intercept, absorb, and then slowly release water, which can reduce adverse impacts of stormwater runoff like stream bank erosion, sediment transport, and the frequency and severity of floods and drought. This is particularly important because stormwater runoff from impervious surfaces is a main source of pollution that affects water quality around the US (pg 12).

Still not sold? Here are a couple economic benefits to urban greening as well.

Remember all those health benefits we discussed? Get this: Here in the United States, an evaluation of the largest 85 cities in the country found that health savings from parks was an estimated $3.1 billion!

In Cleveland specifically, a conservative estimate of value that an urban forest of about 30% tree canopy would provide the surrounding community is approximately $44 million per year in improved air quality, energy savings, and health impacts (pg 132). Plus, studies have tied economics to urban green spaces (specifically trees) as well. 

1. First, Evaluating homes with similar features and varying amounts of surrounding trees, one study found that a 6% increase in home values was found to be associated with the presence of trees; an increase of 3.5 to 4.5% was reported in another study.

2. Second, studies show that shoppers in business districts with robust tree canopy will spend 9 to 12% more for products, travel further and spend more time there.

3. And lastly, urban green space just looks good!

Urban Greening on Vacant Land and Introduction to Vacant to Vibrant

While urban greening can take place in a variety of settings - from busy street sidewalks to elevated rail lines - in this episode we’re focusing on the potential for urban greening on vacant land specifically. Why, you ask? Well, here are two compelling reasons why vacant land is extremely well suited for urban greening.

1. First, the supply of vacant land in our cities is abundant and generally increasing. On average, nearly one-sixth of the land in U.S. cities is considered vacant (i.e., underutilized or uninhabited). Plus, the ratio of vacant land to city size in America increased by 1.3% from 1998 to 2016. This doesn’t account for regional variations. Cities in the American South and Midwest have land vacancy rates of 24% and 21% respectively - tons of existing land suitable for greening.

2. Second, vacant land (as well as vacant homes) can have traumatic impacts on neighborhoods and cities, serving as breeding grounds for drug abuse, crime, and violence... things we know nobody wants around their neighborhood.  Get this: blocks with vacant properties face crime rates twice as high as blocks without them. This makes greening vacant land parcels a key element to larger community revitalization. It’s this particular point that brings us to the emphasis of this episode on urban greening: the Vacant to Vibrant project. 

Vacant to Vibrant is a guidebook written by Sandra Albro based on an urban greening project she led of the same name. Launched in 2009, the Vacant to Vibrant project aimed to transform vacant neighborhood lots into productive green infrastructure assets that simultaneously benefited their surrounding communities. The project focused on three post-industrial cities reinventing themselves after decades of lost jobs - Cleveland OH, Buffalo NY, and Gary IN. These cities all shared three critical elements relative to Vacant to Vibrant’s project goals:

1. Large quantities of vacant land that were unproductive and expensive to maintain,

2. Outdated sewer systems that were creating a need for better stormwater management in the face of a changing climate, and

3. Neighborhoods that had weathered the environmental and social effects of decades of industrial decline.

Let’s quickly highlight Vacant to Vibrant’s methodology to understand why the project provides such a valuable framework through which to analyze urban greening. In each of the three selected cities, the project team selected vacant parcels they determined to be best positioned for urban greening based on a number of criteria. They then examined each parcel along the following three lines to deeply understand the best urban greening solution for that particular lot:

1. Cultural History: understanding how each vacant parcel’s surrounding neighborhood originally developed (who lived there, what their socioeconomic status was, etc)

2. Physical Form: examining soil types, contamination, and other characteristics of the land itself

3. Neighborhood Context: identifying which local organizations are active in the area, how close the site is to existing infrastructure, etc

What makes Vacant to Vibrant unique from many other urban greening projects is its equal emphasis on the social and the environmental needs of urban residents (pg 6). We’ll use the lessons learned by the Vacant to Vibrant initiative as a lens to better understand what makes successful, community-based urban greening initiatives.

What are the success factors and challenges for urban greening initiatives?

Through its in-depth case studies from Cleveland, Buffalo, and Gary, Vacant to Vibrant identifies the critical success factors to urban greening projects on vacant land based on the challenges the project faced over its years of design and implementation. Let’s touch on our two favorites (pg 126).

1. Evaluate the effectiveness of urban greening projects and make adjustments to design post-installation. Sometimes certain green stormwater infrastructure elements don’t work exactly as planned. The Vacant to Vibrant team found it helpful to leave room for adjustments to their design based on what they observed first-hand. For example, rain gardens designed to capture excess water runoff during storms typically work well, but the team found that increasing the permeability of the existing soils by adding leaf compost achieved the same result in a much more cost-effective way (pg 126).

2. Enlist the community in shaping the design of the projects to combat gentrification and strengthen neighborhoods.In our episode #41 on Equity in Cities, we touched on the topic of green gentrification. This refers to the creation of new green space that’s intended to address environmental justice problems. While these new spaces can make neighborhoods healthier and more aesthetically attractive, it also can increase housing costs and property values. Ultimately, this can lead to gentrification and a displacement of the very residents the green space strategies were designed to benefit.

It’s therefore pretty understandable that many residents that Vacant to Vibrant coordinated with expressed real concern about the project. The Vacant to Vibrant team found that understanding the histories of their post-industrial neighborhoods - for example, how they were developed and the types of residents who have historically benefited from development and those that have been excluded - in addition to keeping community dialogue open and utilizing community liaisons, can help these projects sensitively navigate resident concerns about change (117).

Scaling this focus on equity in project planning by elevating equitable urban green space to the level of long-term regional planning is especially important. As a first step, many cities are committing to long-term urban greening initiatives. For example, Pittsburgh’s 12-part, 25-year plan has an open space component called OpenSpacePGH that details land use and infrastructure decisions that affect the city’s 30,000 vacant, distressed, or undeveloped properties. The plan identifies lack of adequate green space as a growing threat (pg 12).

How can you promote urban greening in your city/neighborhood?

Well, number one is simply launching urban greening projects yourself! We found a great article by the nonprofit ioby that walks through 3 easy projects you can start today. They include creating a community garden, banding together with neighbors to create bicycle and pedestrian promenades, and creating multi-purpose community spaces on vacant lots - exactly like Vacant to Vibrant. We’ll link to the article in the show notes on our website.

You can also get involved in your city government or in community groups to champion these sorts of projects on a greater scale. Many cities have some sort of Public Health department that focuses directly on the health of its citizens. Here in Denver it’s called the Department of Public Health and Environment, and they have all kinds of resources on upcoming events and partner organizations on their website.

There are also all sorts of neighborhood nonprofits that exist to promote healthy communities on a more micro scale. Finding them is no harder than googling “sustainable community development groups or urban greening groups near me”.

In fact, there may already be groups providing urban greening services to organizations in your neighborhood that you can engage directly. One example is Greenprint Partners, which consults for cities, water authorities, and property owners on how best to realize the fullest green infrastructure potential. Another example is the Trust for Public Land’s 10 Minute Walk national campaign. Their goal is to have a park within a 10-minute walk of all homes in America.

And finally, you can get politically active. Vote for politicians that express support for urban greening, and of course, don’t forget to check out our episode on Climate Advocacy for additional tips on how to amplify your passion for urban greening.

Island Press and Sandra Albro

Island Press is the nation’s leading publisher of books on environmental issues, like Vacant to Vibrant. It is a 501(c)(3) organization with a mission to stimulate, shape, and communicate the information that is essential for solving environmental problems. 

Sandra Albro, our upcoming guest and the author and Project Manager of Vacant to Vibrant, is the Director of Community Partnerships at Holden Forests & Gardens. She’s also the co-chair for the Cleveland Tree Coalition and the Project Manager for a US EPA Urban Waters project examining the use of soil remediation and green stormwater infrastructure in Cleveland.