Top-Down Greening In The Urban Core

Now available in a Planetizen Podcast are highlights of a speech given at this symposium by Paul Kephart, an ecologist and land-use planner with Rana Creek Restoration Ecology in Carmel Valley, California.

Top-Down Greening In The Urban Core: Coverage of the Los Angeles Green Roof Market Development Symposium

"Nature" is increasingly represented in the urban world as an incidental garnish -- a potted shrub at the door of a towering high-rise; a bush inside the loop of a freeway onramp.

These greening gestures calmly try to suggest a connection between the urban environment and the natural one. Yet other than providing window dressing, they contribute little to counter the harm that cities inflict on the natural ecology.

So what is a densely developed and thoroughly paved American downtown to do?

Such was the topic of discussion at the recent Green Roof Market Development Symposium in Los Angeles. The conference, which was sponsored by Green Roofs For Healthy Cities, an industry association representing thousands of architects, engineers, planners, horticulturists, developers, and policy makers in the U.S. and Canada, was one of many events that the group has organized around the country.

The organization has been working for more than seven years to promote rooftop gardens as a way to get some greenery back into cities while actually improving the environment, and advises local governments, planners and developers on the different methods they can use to implement green roofs.

Attended by nearly 100 developers, planners, architects and public servants, the symposium offered a wealth of knowledge about rooftop gardens, from their design, to the various products used in their construction, to the challenges of convincing developers to double or even triple their roofing costs to integrate plant life. The overall goal of the event was to help develop a rooftop garden plan for Los Angeles.

Many presenters cited the experience of Chicago, where Mayor Richard Daley built a garden on the roof of city hall six years ago. At first the idea was laughed at by many in the city and was considered a big waste of money. But the garden helped the building become more energy-efficient by retaining rainfall in the soil and cooling the building from the top down. The garden roof was built to last twice as long as a traditional roof and has provided the city with praise-worthy scenery where there was only tar before. City hall set an example for the city, and in the six years since its greening, more than 200 other buildings in Chicago are now topped with gardens.

L.A. Seeks to Follow Chicago's Lead

While Chicago is undoubtedly leading the way for American cities, Los Angeles has hopes to try to catch up. To help develop a plan of action, the symposium included planning sessions where attendants brainstormed ways for the city to become more green-roof-friendly. Representatives from the city's Environmental Affairs Department, Department of Building and Safety, Bureau of Sanitation and Department of Water and Power facilitated discussions about how to create incentives for developers to take on the expenses involved with building rooftop gardens, as well as to ensure the gardens can perform in ways that are relevant to the needs of L.A.

In delivering the keynote address at the conference, ecologist and land use planner Paul Kephart called for the integration of nature to be made the most important consideration in any development, especially in heavily urbanized areas. He discussed the importance of planning and designing with nature, and making buildings "perform." Kephart's firm, Rana Creek Restoration Ecology, specializes in reconnecting buildings to nature in ways that are not just aesthetically attractive, but mutually beneficial to the buildings' energy-efficiency and to the environment.

For Kephart, the importance in designing with nature is the duality of purposes. He proposes that the true purposes of development plans be closely scrutinized, especially those claiming to be "sustainable" or "green."

"Is this eco-chic? Is it just being green? Is it doing the right thing? Is it truly about that reconnection with nature, and that philosophical and spiritual alignment with nature?" Kephart asked in his address. "Are we going to paint these buildings green but not be able to use them, and do they have a higher purpose? Do they have a purpose to encourage biodiversity and ecology?"

As an experienced ecologist, Kephart believes strongly in creating green spaces that are as accurate and realistic as possible. This involves choosing the right plant species, thinking about what animal species will live in this tiny rooftop ecosystem, how much water will be collected from rains and how that water will either runoff into the sewers or permeate into the garden and integrate back into the water cycle. But even Kephart, a strong proponent of rooftop gardens, recognizes that an acre of green space 20 stories above the earth’s surface is not exactly the most "natural" form of existence.

"These are very harsh conditions," Kephart says of the rooftops of heavily urbanized areas like L.A. "They're exposed to radiation and extreme temperatures, often the rooftops here will have temperatures as high as 175 degrees, so how do we mitigate for that, how do we look for natural analogs. Where in nature do these kinds of plants and soils occur? And how can we learn from nature to look at adaptation and function?"

Plan of Action

Despite the difficulty of implementing these rooftop gardens, many in Los Angeles are ready to try. City Councilmember Ed Reyes has been one of the city's most vocal proponents of installing rooftop gardens. He was in attendance to introduce Kephart's speech, and he emphasized the purpose of the symposium for generating concrete plans. The council district Reyes represents includes part of downtown, and he has a vision for increasing the green space in urbanized L.A.

But like Kephart, Reyes wants to focus on striving for a purpose when implementing rooftop gardens and other sustainable plans. Reyes is hopeful that the strategies developed at the symposium will push L.A. forward in developing rooftop gardens and help it become a national example like Chicago. He wants L.A. to be recognized all over the world for vast improvements in sustainable design, but also recognized locally by the people for regaining that connection with nature and being a good place to live.

"But it's not only about the social aspect. It's about the ecological element of this, It's about the creativity and design, it's about how do you fold in these green rooftops, these terraces, and transit-oriented districts, how we stimulate pedestrian-oriented areas that connects the rail stations to highly dense pockets of housing that can be connected to meadows and open spaces along the river," said Reyes.

With the symposium concluded, participants walked away educated about the possibilities for rooftop gardens. While the goals presented during the day will not be achieved immediately, many involved with the event felt the action plans developed there will help ensure that the idea of rooftop gardens will not be ignored in Los Angeles.

Nate Berg is Planetizen's Assistant Editor.