The Heritage Garden at Bonnet Springs Park includes hundreds of oaks reclaiming a former railyard. Lakeland, Florida.
Courtesy Sasaki The Heritage Garden at Bonnet Springs Park includes hundreds of oaks reclaiming a former railyard. Lakeland, Florida.

Dear Architecture,

I am Landscape Architecture – your outdoorsy cousin who missed the last few family gatherings. I know this publication is more for your crowd – so I thought posting here might grab your attention.

You see, I’m in a bit of a bind. I see climate change happening in my parks, streets, and coastlines – meanwhile, my designers advocate for planting trees, restoring green space, and carving out space in our cities for bikes and pedestrians. My community has always assumed Landscape Architecture is at the forefront of combating climate change.

The Coastal Waterfront at Ellinikon, a one-kilometer long public beach with coastal gardens, restored dune habitat, and tamarisk and pine woodlands framing a promenade and event spaces. Athens, Greece.
Sasaki The Coastal Waterfront at Ellinikon, a one-kilometer long public beach with coastal gardens, restored dune habitat, and tamarisk and pine woodlands framing a promenade and event spaces. Athens, Greece.

I think your folks have known all along that buildings have big environmental impacts, so you first tackled operational carbon, and now are coming to grips with the embodied emissions to build your structures. You went deep, technical, and introspective, in ways seemingly made possible with the advent of BIM and the critical work around life cycle assessment standards. It’s only in the last few years that landscape designers started to dive into the embodied emissions of landscapes – and we have learned our designed spaces can be just as emissions-intensive as buildings on a per unit area basis. This is more than embarrassing. This is the realization that I have an addiction too.

Euclid Avenue is being redesigned into a new bus rapid transit corridor with urban forestry as key strategy to improve thermal comfort, reduce runoff, and sequester carbon. Cleveland, Ohio.
Sasaki Euclid Avenue is being redesigned into a new bus rapid transit corridor with urban forestry as key strategy to improve thermal comfort, reduce runoff, and sequester carbon. Cleveland, Ohio.

Fortunately, I have been able to learn a lot from your work. Whole Building LCAs are now well understood in your community, tied to rigorous methodologies robust enough to be integrated into government codes (go Calgreen!) and certification systems (well done ILFI!). I thank you for setting the bar, and today I can say the landscape community is catching up. We have our own 12-step program in the ASLA climate action plan to get on the right side of history on this. I can tell you more about that over the holidays.

A the Ellinikon Metropolitan Park, reforestation is a key carbon abatement strategy, with over 13,000 large caliper trees, and more than 49,000 restoration tree saplings, included in the design. Instead of monocultural forestry, these systems are being designed as structurally complex, biodiverse ecosystems, which will ultimately store more carbon. Athens, Greece.
Sasaki A the Ellinikon Metropolitan Park, reforestation is a key carbon abatement strategy, with over 13,000 large caliper trees, and more than 49,000 restoration tree saplings, included in the design. Instead of monocultural forestry, these systems are being designed as structurally complex, biodiverse ecosystems, which will ultimately store more carbon. Athens, Greece.

Upon reflection, I think my blind spot came from the very nature of being a self-identifying green discipline. Your introspection and perspective have made me look at my profession in a new light.

Ellinikon Metropolitan Park in. Athens, Greece.
Sasaki Ellinikon Metropolitan Park in. Athens, Greece.

However, while you've become proficient at accounting for biogenic carbon stored in dead wood for structures, the living biogenic carbon stored on your site – the soils, the plants, and the trees – seems overlooked. Soils along contain 80% of the world’s terrestrial ecosystems' carbon stocks, a delicate balance that requires protection. We have learned how structurally complex ecosystems can net store and sequester more carbon than their simpler and monocultural alternatives, and are more resilient when facing disturbances like disease or climate change.

Understanding the potential of existing site conditions is key for decarbonizing landscape architecture. At the Ellinikon, early field assessments identified trees for preservation, transplant potential, and an understanding of what was thriving on-site without maintenance or intervention, as well as the potential for protecting and amending existing soils. Athens, Greece.
Sasaki Understanding the potential of existing site conditions is key for decarbonizing landscape architecture. At the Ellinikon, early field assessments identified trees for preservation, transplant potential, and an understanding of what was thriving on-site without maintenance or intervention, as well as the potential for protecting and amending existing soils. Athens, Greece.

While many ecosystems have a limit to their carbon-carrying capacity, some are effectively carbon pumps, contributing to ongoing sequestration year after year even after maturity, such as mangroves. There is an overlooked externality for project emissions if we ignore site work, but there is also a missed opportunity if we don’t give credit for the living systems' carbon storage and sequestration capacity. We should value and credit ecosystem carbon at least as much as, if not more than, material carbon stored, especially considering the co-benefits of ecosystem services.

At the Bonnet Springs Park Nature Center, care was taken to preserve existing heritage trees, advance a mass timber approach to design, and restore native understory vegetation. This site has more carbon stored in the adjacent trees and soils than in the wood of the building. Lakeland, Florida.
Sasaki At the Bonnet Springs Park Nature Center, care was taken to preserve existing heritage trees, advance a mass timber approach to design, and restore native understory vegetation. This site has more carbon stored in the adjacent trees and soils than in the wood of the building. Lakeland, Florida.

When considering the carbon storage and sequestration potential in living systems along with that stored in structures, we're better positioned to advocate for sustainably sourced biogenic materials. Current life cycle assessment (LCA) standards credit the carbon stored in sustainably sourced biogenic material (wood, straw, bamboo, etc.) for the equivalent carbon locked in the dry biomass that’s prevented from decaying. What is not considered is the carbon sequestration for those materials when they were alive, which could include carbon sunk into soils or allochthonous carbon that moves through ecosystems. We should also chat about the complexity behind sustainability sourcing from a biodiversity perspective, perhaps next time we get a beer and commiserate over enforcing specs.

I propose we need to collaborate more effectively. I can assist in maximizing the carbon potential of the living systems of the places we build, and you can help me tackle reducing embodied carbon in construction. Together, perhaps we can kick this addiction to carbon in the built environment.

See you at the next family potluck,

Landscape Architecture

P.S. Can you tell Civil I’m making the hot-dish this year? I have a great new recipe - I’ll get her to eat kale and like it ;)

The views and conclusions from this author are not necessarily those of ARCHITECT magazine.

Read more on building a greener world: 10 Transformative Principles | Caring for the Buildings We Have| Putting Decarbonization Back on the Global Stage | Now Is the Time for Radical Collaboration| Can We Halve Carbon in the Built Environment? | The Race to Decarbonize Buildings Is On.| Building on the Best of COP27

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