ASLA Survey: Landscape Architects Call for Greater Collaboration with Product Manufacturers to Reduce Climate and Biodiversity Impacts

ASLA 2021 Professional General Design Honor Award. Ferrous Foundry Park, Lawrence, Massachusetts. STIMSON / Ngoc Doan

Landscape architects see need for new product data and tools to better measure and reduce impacts from their projects

ASLA has released its first national survey on the role of landscape architecture products in achieving decarbonization and biodiversity goals. A cross-section of landscape architects, designers, and landscape architecture educators in the U.S. responded to the survey in June 2023.

According to the survey results, landscape architects seek:

  • Increased collaboration with product manufacturers, universities, and allied organizations to research, analyze, and reduce climate and biodiversity impacts of products.
  • New product data to better measure carbon in projects, including:
    • Embodied carbon factors for materials
    • Projected carbon sequestration of tree species
    • Greenhouse gas emissions of products’ entire lifecycle
  • New local options for 14 product categories to reduce greenhouse gas emissions from transporting products.
  • A new open-source landscape architecture product data library and carbon factor dataset.
  • And to address potential biodiversity impacts, they seek new research and knowledge sharing.

“Our ambitious Climate Action Plan, released last year, called for all landscape architecture projects to achieve zero embodied and operational emissions and increase carbon sequestration by 2040. It also called for all projects to restore ecosystems and increase and protect biodiversity. The products used in projects are absolutely central to landscape architects achieving these goals,” said ASLA CEO Torey Carter-Conneen.

“The survey clearly shows that landscape architects and product manufacturers must deepen their collaboration to reduce the climate and biodiversity impacts of materials in built landscapes. We can only achieve our goals by working together, being more transparent about materials, and increasing our collective performance,” said ASLA National Climate Action Committee Chair April Phillips, FASLA.

ASLA 2021 Professional Residential Honor Award. Quarry Garden. Minneapolis, Minnesota. TEN x TEN / Gaffer Photography

Reducing Climate Impacts

According to Climate Positive Design, some 75 percent of landscape architecture projects’ greenhouse gas emissions result from embodied carbon. These are the emissions released from the manufacturing, transport, installation, and construction of products used in landscape projects. The other 25 percent is associated with operational emissions, which are released by powering and maintaining landscapes.

In landscape architecture projects, there is a need to:

  • Reduce the use of products with high embodied carbon
  • Increase green space that sequesters carbon
  • Use more locally sourced products, which means lower transportation emissions.

Third-party verification of the greenhouse gas emissions from products is another key action because it enables landscape architects to accurately measure the carbon footprint of their projects.

The survey finds that some landscape architects are decarbonizing their projects through the products they specify, but the approach is not yet widespread.

Key survey findings

24% of landscape architects surveyed state that clients are setting greenhouse gas emission budgets for one or more of their projects. 2% stated an emissions budget is in place for all their projects.

56% of landscape architects surveyed ask for third party-verified environmental product data, including Environmental Product Declarations (EPDs), at some stage in the design process.

There is significant demand for specifying local products to reduce transportation emissions. A majority of landscape architects would specify local products from a range of categories if they were available, including:

  • Trees
  • Aggregates and aggregate stabilization
  • Plants
  • Concrete and concrete products
  • Soils and soil amendments
  • Natural stone
  • Brick, tile, and fired masonry products
  • Erosion and sediment control products
  • Bituminous paving
  • Fencing or metal fabrications
  • Wood or wood products
  • Drainage or piping
  • Furnishings
  • Irrigation

To reduce embodied carbon from products and also increase the use of products that sequester carbon, landscape architects see the need for additional industry-wide product data.

The product data most in demand:

  • Embodied carbon factors of materials, which measures the embodied greenhouse gas emissions per mass of a given material
  • Projected carbon sequestration by species of trees
  • Greenhouse gas emissions of products’ entire lifecycle
  • Greenhouse gas emissions for transporting products to project sites
  • Greenhouse gas emissions savings from the use of innovative materials

To move forward, landscape architects called for:

  • Additional education
  • Creation of a shared, curated product data library
  • Best practices for landscape architects, product manufacturers, and the construction communities.
  • Creation of a shared, curated carbon factor dataset for materials

Reducing Biodiversity Impacts

Products used in landscape architecture projects can have adverse impacts on biodiversity and ecosystems.

Products that include mined, extracted, or harvested materials or certain chemicals can potentially negatively affect species and ecosystems. The construction and installation of products can also impact ecosystems in and surrounding project sites.

There is currently no standard way to measure the biodiversity impacts of products used in landscape architecture projects, with the exception of wood products, which can be certified by the Forest Stewardship Council (FSC) and tracked through chain of custody approaches. Other tools evaluate the chemical content of products.

To reduce potential adverse biodiversity impacts from products, landscape architects called for:

  • Additional education
  • Knowledge sharing between product manufacturers and landscape architects at the ASLA Conference on Landscape Architecture
  • Funding an industry-wide biodiversity protection product protocol
  • Trend analysis on current approaches to reducing biodiversity impacts from construction

Product Manufacturers’ Perspective

In June 2023, ASLA also polled product manufacturers that represent more than 30 product areas and industries. 48 product manufacturers responded. Given there are an estimated 6,000 manufacturers marketing products to landscape architects, this poll doesn’t constitute a representative sample.

34% of product manufacturers polled stated they have plans in place to further decarbonize their products or manufacturing process and are making investments to achieve these plans.

30% stated they have measured greenhouse gas emissions from their product manufacturing process. 26% have measured the emissions from sourcing materials.

The ASLA Climate Action Committee and ASLA Corporate Member Committee, which includes product manufacturers, are developing a series of free webinars to support landscape architects and product manufacturers in decarbonizing projects and processes and improving biodiversity outcomes.

See the full results of the member survey and a poll of product manufacturers

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