dirt.asla.orgTHE DIRT – UNITING THE BUILT & NATURAL ENVIRONMENTS

THE DIRT – UNITING THE BUILT & NATURAL ENVIRONMENTS Skip to content Primary Menu Home RSS THE DIRT by E-mail About Submissions Search Search for: THE DIRT UNITING THE BUILT & NATURAL ENVIRONMENTS Interview with Meg Calkins: The Case for Sustainable Landscape Materials 01/15/2020 01/17/2020 Jared Green Leave a comment Meg Calkins, FASLA Meg Calkins, FASLA, is the department head and professor of landscape architecture at North Carolina State University. She is a contributing editor to Landscape Architecture Magazine , a founding member of the Sustainable SITES Initiative® (SITES®), and author of Materials for Sustainable Sites: A Complete Guide to the Selection, Evaluation and Use of Sustainable Construction Materials and The Sustainable Sites Handbook: A Complete Guide to the Principles, Strategies and Best Practices for Sustainable Landscapes . Interview conducted at the ASLA 2019 Conference on Landscape Architecture in San Diego. Over the past few decades, how much progress have we made towards achieving sustainable landscapes? What practices promoted through the Sustainable SITES Initiative® (SITES®) have landscape architects now widely adopted? What low-impact material alternatives do landscape architects now widely use? In general, we have made strong progress toward sustainable landscapes in some areas. Green infrastructure — including bioretention, bioswales, rain gardens, even green roofs — are now pretty widely used, especially in urban environments. Their performance and cost benefits are well-documented. Landscape architects are getting a handle on how to employ them in a functional and artful way. Landscape architects are also starting to speak the language of civil engineers and doing great collaborations in the area of stormwater management. This whole area of SITES and sustainable site design has been really successful. ASLA 2019 Professional General Design Honor Award. Chulalongkorn University Centenary Park, Bangkok, Thailand / LANDPROCESS Landscape architects are also designing with native plants and plant communities in mind, and many are avoiding invasive plants. If only we could get the nursery industry to not stock invasive plants, we would be OK. But even in urban settings, landscape architects are conceiving of plant communities as habitat as well as having aesthetic value. Where are the major gaps? Where does progress need to happen the most? Use of materials with reduced environmental and health impacts are lagging behind. This is because clear and comparable information about the carbon footprint, resource use, manufacturing impacts, and toxicity of materials and products is not widely available. Information transparency is perhaps the biggest challenge when trying to reduce the environmental and human health impacts of materials and products. LEED, SITES, and the Living Building Challenge offer credits encouraging information transparency, but these credits are still among the least achieved. Product manufacturers do not provide information on embodied carbon, resource use and waste, energy and water use, and toxicity impacts. Human health impacts may be the most challenging to identify given many manufacturers claim the constituents of their products are proprietary and therefore will not release information on the types of chemicals used or produced and their quantities. The habitat and cultural impacts of raw material extraction are often an out of sight out of mind issue. For example, we don’t see the impacts of harvesting tropical hardwood lumber from the Amazon, so it doesn’t seem so problematic to use it. We don’t see the ecosystem decline after the removal of the keystone species tree that is cut to make tropical hardwood lumber. We don’t hear about the murders of indigenous people to intimidate them to leave their protected land so tropical hardwoods can be harvested. And we don’t know that there is a 78 percent chance that the tropical hardwood we are using was harvested illegally (Greenpeace 2014). Through Climate Positive Design , Pamela Conrad, ASLA, has devised a comprehensive approach for designing and constructing landscapes so they sequester more carbon than they emit over their lifespans, transforming them into net carbon sinks. Through her design toolkit, she recommends swapping carbon-intensive materials with lower-carbon options and planting more greenhouse gas-absorbing trees and shrubs. As you just mentioned, one of the issues you have identified is the lack of third party-verified environmental product declarations with publicly accessible data. How can we get full transparency around the environmental impact of landscape products? First, I want to say that balancing carbon onsite is a critical aim, and Conrad’s design toolkit is wonderful. It’s going to have a transformative impact on site design and material and product specifications. Embodied carbon of materials is a far more accurate indicator of the impact of producing a building material or product than embodied energy. Embodied energy is not as accurate because all energy sources do not have equal impact on the environment. Some will be almost carbon neutral, like wind power, and others, like coal, will have very high embodied carbon and a substantial environmental footprint. But while carbon considerations are heavily prioritized in decision making in the building fields, they do not tell the whole story. The human health impacts of materials and products, which can be very substantial, tend to fly under the radar. PVC , a plastic that is used in countless construction products, has lower embodied carbon than some other plastics, but it can be extremely toxic to humans in manufacture, use and disposal, particularly if it is burned or heated to very high temperatures. Designers need to consider these impacts, but the only way they’re going to know about them is for manufacturers to tell us exactly what is in the products and what by products are produced. Information transparency by product manufacturers is an area that lags behind other sustainability considerations. I did a content analysis study back in 2012 of the websites of all exhibitors at the 2012 ASLA conference. We looked at what kind of information they’re providing on the impacts of their materials and products, and the steps they’re taking to make them more sustainable. Less than 1 percent provided either life cycle assessment (LCA) or environmental product declarations (EPD) . I’m replicating that study right now, seven years later. I don’t have the results yet, but I suspect it’s going to be closer to 10 percent providing that kind of information. There is progress being made, but we still not enough information for designers to use to compare similar products. SITES and LEED have likely had a slight transformative impact on the information that product manufacturers provide. But the fields of architecture and interior design are ahead of us. If we did a content analysis of their product websites, we would probably find somewhere between 20 and 30 percent provide environmental product declarations. The main way to address the lack of information is for landscape architects and designers specifying site construction products to talk to product manufacturers and ask for information about the environmental and human health impacts of their products. Telling manufacturers — “Well, I’m considering using your product but your competitor, Company X, has an environmental product declaration, so I’m going to go with them” — is only way to make it happen. Of course, one can earn LEED and SITES credits for companies that offer some material transparency. But I don’t know if that’s making change as much as designers constantly asking for that information. Concrete production accounts for around 8 percent of global greenhouse gas emissions. Cement, which is a primary ingredient in traditional concrete, is the second-most used natural resource after water. You have written about ...