Livable Communities through Urban Forestry: Part 2

By Suzanne H. Crowhurst Lennard


Parks are not the only way to increase the number of trees in the city, and the access to green areas. And indeed, the concept of the park – where it is, how large, what shape, and whether wild or cultivated - needs a little rethinking. Urban waterways, green streets, green buildings, community gardens also provide strategies for increasing the urban forest and access to nature.


More important than just more, bigger parks is how accessible a park is. It is not sufficient to draw a quarter mile radius around the periphery of a park to determine how many people that park serves. Some large parks may be fenced, with only one or two entrances, so a quarter mile walk from that entrance may only reach a handful of homes. On the other hand, a small strip park alongside a stream in a densely populated area in the center of the city may offer easy access to thousands of families living within a quarter mile walk.



More trees and parks in poor neighborhoods:

The great scandal in the US is that while white and more affluent communities often have many old-growth trees and are well supplied with parks, low-income and ethnic neighborhoods have fewer parks[1] . This inequality clearly contributes to the lower health levels in poor neighborhoods. Poor neighborhoods are in greater need of street trees, and easy access to parks and community gardens than are wealthier neighborhoods. Following Kardan’s suggestions[2], one powerful way to make a city healthier would be to plant 10 trees per block in poor neighborhoods.

Create Green Fingers:

We need to follow the examples of new neighborhoods such as Vauban, in Freiburg, Germany that connect the green places, for the sake of humans and biodiversity. A small stream running along the southern edge of the Vauban neighborhood is protected as a natural area, and from this, three green fingers reach deep into the neighborhood, providing undisturbed natural habitat, natural play areas for different ages, and simple community areas for barbecues and social events.

The city of Portland is justly proud of its Park Blocks that run almost continuously for 17 blocks north to south through the city center. This extensive linear park contains 335 mature elm, oak, and maple trees and a rich assortment of wildlife, as well as human life. Portland is attempting to create additional natural corridors by linking neighborhood parks with green streets. The ultimate aim is to enable these green streets to function as biodiversity corridors.  

Restore Urban Waterways:

Many of our cities used the river as their industrial heart. Rivers and river banks became polluted, unsuitable both for nature and for humans. Many cities have made major efforts to reclaim the industrial banks and clean the rivers, but there is much still to do. Trees such as willows need to be planted to help foster biodiversity, and to reconnect the regenerative power of the land-water interface. Ljubljana just won title of 2016 Green Capital of Europe in large part for their admirable restoration of their river banks.

Streams are biodiversity corridors but most streams in our cities have been channeled underground so as not to interfere with our use of the surface for construction and car access. Wherever possible we should try to bring them back to the surface as urban streams.

This has been accomplished in numerous European cities and towns. Freiburg, Germany uncovered the tiny streams called Bächle that run off the Black Forest through the streets of the old city, and these are now used to paddle in, and cool hot feet in the summer. The university town of Tübingen, Germany uncovered a stream that ran through the historic heart of the city. It now helps to cool the air in summer.

In slightly less dense urban areas it is possible to restore the stream’s natural banks. The reconstructed town of Plessis-Robinson, just south of Paris has restored streams and lakes as a central feature of their development, creating walkways, parks, and gardens along the banks.

Green Streets:

Streets are potential green fingers and biodiversity corridors. A few trees can encourage social life on the street. More trees, diverse trees, and a mix of bushes, earth, and rainwater ditches can foster greater species diversity. Street trees also help clean the air.

In Vauban, Freiburg, the narrow residential streets are an extension of the green fingers. These are Wohnstrasse (Living Streets), intended for children’s play, bikes and pedestrians. The only reason a vehicle is allowed in is for delivery or emergency access. Only handicapped residents are allowed to park there. Permeable stone lined rainwater channels are provided by the city, and residents may choose what tree they want in the strip owned by the city.

Vauban also has a network of traffic-free bike/pedestrian lanes through the most heavily wooded sections of the development.

Green pedestrian networks are also needed into and around the city center, to provide healthy pedestrian commuter routes. Almost every small town in England has a fine web of almost secret green rights of way that weave into the town center, nipping between houses and along the banks of streams in the suburban areas, through city blocks and along the borders of parks in the city center. Poundbury has created such a wealth of these pedestrian short cuts that the streets themselves sometimes seem deserted.

In Krakow, Poland a major pedestrian commuter route leads into the city center through a park.

In quiet neighborhoods, such as Carmel, or Berkeley, California trees also perform a grand job of calming traffic. This is a model easily adopted by residential neighborhoods.

Arterial roads carrying a great deal of traffic are in major need of greening to reduce pollution and slow traffic. This is especially important when the roads have stores and residential buildings on either side that require the ability to easily and safely cross the street. In these situations, even roads carrying heavy traffic need to widen sidewalks, add buffered bike lanes, reduce the number and width of traffic lanes, add crosswalks and roundabouts, and plant trees.

Green Buildings:

Trees can also help to provide green walls and roofs. In addition to climbers and vines trained on a scaffold across a façade, fruit trees have traditionally been grown in this way. Just imagine, leaning out of your bedroom window and picking a fresh pear for breakfast!

Trees can also be grown on roofs and terraces. Green roofs improve biodiversity, slow rainwater and keep buildings cool. Even green arbors, vines, small trees and gardens in pots on roof terraces – as can be seen on every other rooftop in Rome - help to cool the atmosphere, without requiring immensely high-tech structural solutions.

The most successful and well-tested projects I have seen are those by the artist Friedensreich Hundertwasser. The Hundertwasser House in Vienna is public housing commissioned by the City. It is human scale – 5 and 6 stories – with gardens and trees on terraces and on the roofs. The building is beloved by residents and tourists.

Hundertwasser has designed dozens of buildings all over Europe, but perhaps his most ambitious project is Bad Blumenau, an extensive spa village in Eastern Austria. Each building is a little hill, covered with grass and trees, creating a rolling green landscape. Here, the spa park is atop the buildings.

Trees in Urban Public Places

We have a huge need in North America to rebuild community, regenerate a social network and increase democratic dialogue and civic engagement. This is important for many reasons, including the social and physical health of the population. Preventative action on the level of creating a healthy environment would also save billions of dollars in health care expenses.

Researchers in public health and social science have discovered that when people are tied into a rich daily pattern of face-to-face interaction with friends, familiars and neighbors, they do not fall ill so often, if they get sick it is not so serious, and they live to a riper old age. They have what is called a strong “Social Immune System”.

It is a central tenet of IMCL that we desperately NEED more Community Places – squares and piazzas that generate social interaction. It is absolutely essential to bring people together, to build community in neighborhoods, to facilitate civic engagement and strengthen social immune systems.

Trees are an essential tool for achieving that goal. They shape social life.

In a community place, a tree creates the ideal location for an outdoor cafe or restaurant, or for public benches where elders can sit and watch the children playing, or lovers can embrace. A broad canopied tree filtering the sunlight will enhance a café or restaurant. A smaller tree giving dark shade will provide a cool corner for a couple of benches.

Trees keep the paving cooler. So a square with many trees supports many conversations on the move, peripatetic, as people’s paths cross, while they make errands, commute to and from work.

Whenever we want to bring people together in the city, trees must play a major part. Outdoor farmers markets, like those in Aix-en-Provence, or on Portland’s South Park blocks, benefit from the trees. The plane trees in Aix, and the oak, elm and maple trees in Portland keep the produce fresh, and make the market even more inviting for humans.

Munich’s Viktualienmarkt, a combination of a vast farmers market and beer garden, at the heart of Munich, is magnificently shaded by chestnut trees.

We need more public squares that are free of traffic, where people shop, meet, walk, eat out, meet friends, and enjoy their city, and these squares need trees!


This is the second part of a talk presented at the Livable Communities through Urban Forestry Conference in Washington DC, August 6, 2015 by Suzanne H. Crowhurst Lennard, Ph.D. (Arch.), Director, International Making Cities Livable Conferences.


[1] Estabrooks PA1, Lee RE, Gyurcsik NC. (2003) Resources for physical activity participation: does availability and accessibility differ by neighborhood socioeconomic status? Ann Behav Med. 2003 Spring;25(2):100-4.

Powell LM, Slater S, Chaloupka FJ, Harper D. Availability of physical activity-related facilities and neighborhood demographic and socioeconomic characteristics: a national study. Am J Public Health. 2006;96:1676–80.

[2]  Kardan, O. et al. Neighborhood greenspace and health in a large urban center. Sci. Rep. 5, 11610; doi: 10.1038/srep11610 (2015).