The plan and guide chart a pathway for landscape architects to achieve zero greenhouse gas emissions in their projects and operations and increase carbon sequestration by 2040.
The plan was developed by a high-profile Task Force of five landscape architects chaired by Pamela Conrad, ASLA, founder of Climate Positive Design, and a 17-member Advisory Group. It outlines a bold vision for 2040 and a set of 71 actions to be taken by 2025.
By 2040, all landscape architecture projects will simultaneously:
Achieve zero embodied and operational emissions and increase carbon sequestration
Provide significant economic benefits in the form of measurable ecosystem services, health co-benefits, sequestration, and green jobs
Address climate injustices, empower communities, and increase equitable distribution of climate investments
Restore ecosystems and increase and protect biodiversity
Watch a 13-minute overview of the vision and goals of the plan by ASLA CEO Torey Carter-Conneen during the ASLA 2022 Conference opening general session (see video above).
Then, watch a 60-min presentation on the three goals and six key initiatives of the plan and field guide:
Speakers include the ASLA Climate Action Plan Task Force:
Along the Gowanus Canal in Brooklyn, a 118-year-old power station has become Powerhouse Arts, a contemporary arts and fabrication space. To protect its waterfront from storm surges and sea level rise, landscape architecture firm Ken Smith Workshop layered in steel and concrete defenses. But they also wove in a nature-based solution to capture stormwater. “It’s both a defensive measure and a living shoreline that will make the site adaptable,” said Ken Smith, FASLA. “It’s how we could use a tight space with a steep slope to do a lot.”
The power station, built at the turn of the 20th century, once housed coal-powered turbines that generated electricity. The three-story red brick building was developed by the Brooklyn Rapid Transit Company. It was decommissioned in the late 1930s and by the 1970s reborn as a cardboard incinerating facility. Since then, it has had many lives, becoming home to both artists and squatters. Some of the city’s best graffiti artists left their mark. And in recent decades, it became known as the Batcave, a place for dance parties.
After starting a foundation, hedge funder Joshua Rechnitz purchased the building in 2012. He then hired architects Herzog & de Meuron and PBDW to renovate the power station and graph on a six-story annex, essentially doubling the square footage. “They brought rigor to the project, maintaining the architecture in as straightforward a way as possible,” Smith said during our hardhat tour.
The foundation and architects re-imagined the space as a contemporary artist and fabrication studio that will offer community classes, prototyping spaces, job training, and public exhibitions. But they also wanted to keep its layers of history, including the graffiti.
Exiting the rear of the Powerhouse, the expanse of the Gowanus Canal, one of the most contaminated Superfund sites in the country, came into view. It’s a water body that also continues to receive millions of gallons of combined sewer overflow each year.
The canal has drawn in number of landscape architects over the years. Susannah Drake, FASLA, and her firm DLANDStudio, created the Gowanus Canal Sponge Park™. That began as a plan for lining the 1.5-mile-long canal with absorbent green spaces that could reduce stormwater from further polluting the waterway. An 1,800-square feet pilot sponge park was then completed in 2016 and now captures some 2 million gallons of stormwater each year.
And in 2018, SCAPE Landscape Architecture partnered with the community to create the Gowanus Lowlands Masterplan, a vision for restoring public spaces and the ecology of the canal and its watershed. SCAPE dove into the history of the Gowanus Creek ecosystem that once existed. In the 1850s, the creek was hardened, becoming what is is today — a canal for transportation and industrial manufacturing.
Smith said that during Superstorm Sandy, which pummeled the city in 2012, the canal’s polluted waters rose up by 12 feet, flooding the area. Working with limited space, he decided to reinforce the Powerhouse Arts waterfront with a steel sea wall and concrete yard blocks, protecting it from future storm and climate impacts. “The site was raised considerably. To be good citizens, we went with armature.”
Before Smith began his work, the existing waterfront edge was 5.8 feet above sea level, so not enough to protect against a future storm surge. With the engineering team, Smith brought in 225 feet of black steel sheet pile walls, which were driven 40 feet down into the canal bank. The top of the new sheet pile sea wall is now 10 feet above sea level — higher but not enough for the greatest anticipated storm surges. On land, the sea wall is about the height of an armrest for Smith, 3-4 feet off the ground, so possible to see over.
Behind the sea wall, Smith wove in a 12-foot-wide gravel walkway, ensuring public access to the waterfront. From the back of that path, stepped rows of concrete yard block walls add another 12.75 feet of protection. The 366 concrete yard blocks, sometimes called “mafia blocks,” are lined up in precise rows. The top of the slope is now 19.5 feet above sea level.
Smith said he also used hardcore materials like steel and concrete because he wanted to maintain the site’s “industrial vocabulary.”
He sees potential in this humble grey infrastructure: “Gabions used to be utilitarian; now they are quite fetishized. Concrete yard blocks will become the next gabion.” (And, hopefully, it’s eco-concrete that will be fetishized).
The blocks were also purposefully positioned so they are multi-functional: “They are usable; you can sit on them.”
Above the blocks is a vegetated buffer filled with trees and meadow grasses that will capture water coming from the Powerhouse parking lot. “The beach plum, coffee, and red cedar trees are tough” and will ensure that living shoreline element will endure.
Boulders were plopped to offset the rectilinear building. “I didn’t want the landscape to be too straight forward and direct. I wanted to create an interesting frame for the building.”
Crossing a bridge to the other side of the Gowanus Canal, Smith remarked that the canal is a highly polluted place that is being rapidly re-zoned as a residential area.
Standing at the Sponge Park, and looking across the canal at Powerhouse Arts, one could see a variety of waterfront landscapes — some clearly green spaces associated with residences, some public spaces, and some linked with legacy manufacturing sites. The ad-hoc approach to waterfront resilience in NYC was apparent.
Nature-based solutions to storm surges, such as mangroves and wetlands, are ideal but require enough space on shore. Constructed islands, berms, and reefs can reduce wave power from storms off shore but require enough space in the water and distance from the land.
What is the solution along highly developed canal and river communities where set-backs or off-shore solutions aren’t possible? In many places, New York City has been lifting up, adding elevated park structures as well as sea walls to its waterfront. The Powerhouse Arts project says here, at least along this stretch of canal, resilience means armor. But this also means the next mega storm, made more destructive by climate change, will surge in elsewhere.
The ASLA Fund invites landscape architecture educators to develop succinct and impactful research reviews that investigate evidence of the benefits of landscape architecture solutions to the climate and biodiversity crises.
The goals of the research reviews are to:
Understand and summarize the current state of knowledge.
Synthesize the research literature and provide insights, leveraging key data- and science-based evidence.
Create accessible executive summaries in plain language for policymakers, community advocates, and practicing landscape architects.
Over the next few years, research grants will be issued to explore solutions to a range of issues, but the first two grants in 2023 will focus on:
Landscape Architecture Solutions to Biodiversity Loss ($12,500)
Landscape Architecture Solutions to Extreme Heat ($12,500)
“We need landscape architecture educators’ advanced research skills to build the evidence. Working together, landscape architecture educators, practitioners, and students can help us achieve the goals of the ASLA Climate Action Plan,” said ASLA President Emily O’Mahoney, FASLA.
“Landscape architecture educators are key to driving forward research on solutions to the climate and biodiversity crises. This critically important work helps build the foundations for landscape architecture as design science and support efforts to designate landscape architecture a STEM discipline,” said ASLA CEO Torey Carter Conneen.
The research grant period will run from June to the end of this year. The research surveys will be peer reviewed.
The grants are open to landscape architecture educators who are currently affiliated with a university, have a graduate degree, and have published at least one peer-reviewed research paper.
New research published in The Lancet has found that increasing tree cover in European cities to 30 percent could have reduced premature deaths from urban heat islands by 40 percent.
Currently, the average tree canopy in cities across the continent is approximately 15 percent. Increasing tree coverage to 30 percent would cool cities by 0.7°F (0.4°C) — showing that even seemingly small reductions in summer temperatures could save many lives.
The climate crisis has increased temperatures across Europe and led to more dangerous heatwaves. Last year, the continent experienced its hottest summer and second warmest year overall, which only increased the impacts of urban heat islands.
Heat islands form in urban environments comprised of dark, heat-absorbing materials like asphalt, concrete, and tar-covered roofs. These islands are also found in areas where is a high population density, which means a high number of air conditioners expelling heat, and a lack of trees and plants.
And this is confirmed by previous research. In a study of the West Midlands, United Kingdom cited by the authors, “urban heat islands were estimated to have contributed around 50 percent of the total heat-related mortality during a 2003 heat wave.”
“We already know that high temperatures in urban environments are associated with negative health outcomes, such as cardio-respiratory failure, hospital admission, and premature death,” explained lead author Tamar Iungman, with the Institute for Global Health in Barcelona, Spain. And hotter temperatures and deadlier heat islands will lead to an even “bigger burden to our health services over the next decade.”
The researchers used data from 2015, the latest continent-wide population study, to estimate the summer mortality rates of 57 million Europeans in 93 cities, aged 20 years and older. From June to August 2015, the cities were 2.7°F (1.5°C) warmer on average than surrounding rural areas.
The researchers first looked at a range of strategies to reduce heat islands. The majority are solutions landscape architects plan and design:
Green roofs and walls
Light-colored building roofs, walls, and landscape pavers
Replacing impervious surfaces with plants and soils
Increased tree coverage
But for this study, the researchers decided to hone in on trees. They argue that “planting urban trees offers an important opportunity to mitigate high temperatures and, compared with other strategies, is relatively simple and cost-effective to implement.”
Trees are known to be effective at cooling cities — through the shade they provide and the water vapor they release through transpiration. A study cited by the researchers found that in 600 cities trees cooled urban neighborhoods by an average of 1.8°F (1.1°C) — and up to 5.2°F (2.9°C).
Other studies have backed the 30 percent tree canopy target, which is why many cities have set that as a policy goal as well. “Previous epidemiological studies have suggested health benefits associated with tree coverage of at least 30 percent, including reduced odds of incident psychological distress, and non-communicable diseases, such as diabetes, hypertension, and cardiovascular disease.”
Another study found that if European city leaders met World Health Organization recommendations and ensured all their populations lived within 1,000 feet (300 meters) of a green space, 20 deaths per 100,000 people could be avoided each year. This speaks to the importance of distributing trees equitably across all neighborhoods and focusing on historically marginalized and underserved communities with lower tree canopies.
According to The Lancet study, the cities with the highest number of deaths that can be attributed to urban heat islands were in “southern and eastern Europe, particularly in Spain, Italy, Hungary, Croatia, and Romania,” while the lowest were located in “northern Europe including Sweden, Estonia, UK, and northern France.”
Most of the cities with the worst heat islands were also the most densely populated. Dangerous heat islands were found in Paris, France; Thessaloniki and Athens, Greece; Bilbao, Spain; and Brussels, Belgium. These cities have population densities that range from 7,272 to 21,462 people per square km.
The researchers argue that denser cities with lower than average canopies can therefore see even greater benefits from increasing their tree cover than other cities. The issue is finding ways to retrofit these cities to add more trees — a challenge landscape architects can address by adding in new parks, recreational areas, green roofs, and green streets.
Premature deaths that can be attributed to hotter urban temperatures also vary greatly across cities. For example, there were no summer heat-related deaths in Goteborg, Sweden, but 32 premature deaths per 100,000 people in Cluj-Napoca, Romania, The Lancet notes.
Trees were also found to significantly reduce the effects of heat islands during the day because they provide shade along with transpiration. But at night, “the urban canyon (i.e., the geometry formed by a city street and its flanking buildings) more strongly determines urban heat island effects.”
“The night-time intensity of the urban heat island effect is on average three times the daytime intensity. Therefore, urban green infrastructure strategies need to be accompanied by other interventions—especially those that reduce night-time urban heat island effects—to achieve health benefits, such as changing ground surface materials (e.g., from asphalt to granite) and structural interventions that change the sky view factor (i.e., the fraction of visible sky relative to street geometry and building density),” the researchers write.
The researchers’ analysis is based in a “coarse spatial resolution” (1,600 feet by 1,600 feet squares), so it’s not precise. The researchers also note that data on urban tree transpiration rates is hard to measure at a city scale. Typical urban trees’ transpiration rates may be more limited than trees in large parks or the suburbs, because they are “often exposed to harsh conditions (paved soils, air pollution).” The researchers also didn’t factor in how transpiration rates or the shade generated differ by tree size or species. And there was no discussion on how water bodies and features in cities could help further cool communities.
All projects submitted for the prize will be published in the biennial’s book catalogue and featured in an exhibition in Barcelona, Spain, and a website. And 7-11 finalists will be invited by the prize jury to go to Barcelona and lecture at the biennial symposium, which will be held November 27-28, 2023.
The prize jury includes:
Gareth Doherty, ASLA, associate professor of landscape architecture at the Harvard Graduate School of Design
Martha Fajardo, a Colombian landscape architect and architect
Julio Gaeta, an architect and founder of ELARQA, a research center
Kotchakorn Voraakhom, International ASLA, founder of Landprocess
The organizers state that since the first biennial in 1999, the prize has been a “barometer” of “trends, social concerns,” and achievement in the field of landscape architecture. Prize winners reflect the best examples of “intervention [in] and recovery of landscape and territory.”
“We heard from the community that they want the city to take better care of the park — to pick up trash, improve the bathrooms, reduce the pressure of invasive plants, and restore the landscape to optimal health in a thoughtful and steady way,” said Kristin Frederickson, ASLA, a principal at Reed Hilderbrand.
What the landscape architecture team created is a bold plan that balances immediate maintenance and restoration needs with steps to achieve a long-term vision of improved access, resilience, and equitable benefits. The 450-page plan will take multiple decades and more than $150 million to complete. “And the plan suggests that the city and community can’t pick and chose between addressing climate change, equity, historic preservation — these are synergistic elements, key principles meant to operate together.”
The revitalization of Franklin Park has been a long time coming. For decades, one of the city’s largest parks received little government investment and was instead left to the Franklin Park Coalition to steward and maintain. “They deserve a lot of credit — they have been holding this park together. There were times when visitors were actually driving through the park lawns,” Frederickson said.
The city’s history of racial inequities factors into this. Franklin Park is bordered by some of Boston’s most historically marginalized communities — Roxbury, Dorchester, Mattapan, and Roslindale — along with Jamaica Plain, a wealthier community.
Boston’s 2030 plan highlighted the need to invest in Franklin Park. “There was a realization that we need to stabilize the park in order to save it,” said John Kett, ASLA, principal in charge at Reed Hilderbrand.
The first step was to build trust with communities that have been promised support in the past, but didn’t see that translate into action. The first community engagement meeting, pre-pandemic, brought out more than 300 community members. “There was a lot of excitement but also skepticism,” Kett said.
These meetings brought up issues of representation. “Three-fourths of the surrounding neighborhoods are historically underserved. Residents from Jamaica Plain were very active and showing up, but we weren’t hearing much from the underserved communities at first.”
The Franklin Park Coalition, which had established community support and connections over decades, was key to increasing the involvement of these communities, particularly during the pandemic when the team relied on Zooms and online surveys. The coalition helped the team get hundreds of survey responses.
To build trust, Reed Hilderbrand, Agency Landscape + Planning, and MASS Design Group also participated in playhouse in the park, a long-running summer series. For years, community members have brought their lawn chairs and coolers to watch free performances.
“We set up a pop-up photography booth with Sahar Coston-Hardy, who was able to print portraits in the park, and put them up on clotheslines. People looked good, so by the end there was a line. It was a trust-building exercise with the community — and for them. They shared their stories about the park with us, too.”
Brie Hensold, Hon. ASLA, co-founder of Agency Landscape + Planning, explained that additional community engagement strategies included walking tours in the park and in-depth conversations with key constituencies — the groups that cared most about improving the golf course or tennis courts, restoring the woodlands, or enhancing the playhouse and its amphitheater. And to overcome the digital divide among community members, “we also went canvassing door to door to gather input.”
The result of this equitable community engagement is a plan that calls for spreading investments throughout the park, so that all the communities bordering the park see both immediate and long-term benefits.
In her announcement of the new plan to revitalize Franklin Park, Boston Mayor Michelle Wu highlighted two priorities.
“She focused on the need to restore the ecosystems in the park and also the need to appoint a dedicated park superintendent,” Kett said.
A slew of Boston and state agencies are involved in the park and its boundary areas. Establishing a leader who can move the plan forward was a key goal for the planning and design team.
The plan explored how the park could support affordable housing protections, and build capacity, create more local jobs, and develop the workforce, particularly through city government contracts to nearby vendors. These efforts will require multi-agency partnerships across the city government, which a superintendent can help facilitate.
“Given that trust with surrounding communities has been broken for decades, rebuilding that trust will be a slow process. We focused on only promising what we could deliver,” Kett said.
“The community wants to see continuous maintenance improvements and capital investments over time,” Hensold said. “Trust is a longer-term project.”
Through their journey with the community, the team learned that Olmsted’s design is still deeply appreciated. Even with a clear lack of maintenance and investment, the park still has a “rough beauty,” Frederickson said.
“People love this park; they just want it to be a better version of itself. At the core, people want the park to be taken care of.”
Olmsted’s design still resonates despite the insertion of a hospital, zoo, golf course, widened circuit road, and a four-lane road that diagonally cuts through the park.
“There is the sense that Olmsted reached a logical conclusion in Franklin Park, which is one of his later parks. He did less here; it’s more about putting the land forward,” Frederickson said.
Inspired by the rock outcroppings of the area, he reinforced the edges with stone walls and slopes, creating an “interior haven.” Today, that means that some of the park boundaries are “not super porous.” The plan focuses on “improving porosity where we can” through new accessible entrances better aligned with well-lit crosswalks and supported by new street improvements, parking, and bicycle infrastructure.
The core design of the park remains though. Olmsted followed the flow of “whale-shaped drumlin fields, lacing circulation through them.” The design team recommended reducing or eliminating vehicle access in parts of that circulation system to ensure the park feels safer for pedestrians and cyclists. “But the plan is not anti-car. We actually increase parking in areas,” Frederickson said.
And restoring the varied ecosystems in the park, including its marshes, meadows, and woodlands, remains a top priority for the community and the landscape architects. “It’s an incredible, moving place to be. Its rough beauty is its power. It just needs support.”