REFER REPORT
Asahi Kasei Homes Corp. (Head office: Chiyoda-ku, Tokyo; President and CEO: Kawabata Fumitoshi; hereinafter “Asahi Kasei Homes”), Sekisui House Ltd. (Head office: Kita-ku, Osaka; President and CEO: Nakai Yoshihiro; hereinafter “Sekisui House”), and Daiwa House Industry Co., Ltd. (Head office: Kita-ku, Osaka; President and CEO: Yoshii Keiichi; hereinafter “Daiwa House Industry”) (hereinafter “the three companies”) have jointly evaluated the effectiveness of their collaboration in making cities nature positive, based on analysis by Think Nature Co., Ltd., to demonstrate the synergy in biodiversity conservation effects of each home builder’s urban greening efforts focusing on native tree species toward achieving the international goal of becoming nature positive by 2030.*1 This is the first time*2 that home builders have collaborated to evaluate biodiversity conservation activities.
Analysis based on planted tree species data this time clearly demonstrated that the unique initiatives of each of the three companies focusing on native tree species complemented each other ecologically, demonstrating the synergy in the effectiveness of nature positive. In light of these results, as housing manufacturers that supply many homes and buildings to urban areas, the three companies will promote planting proposals focusing on native tree species throughout the housing and real estate industry, contributing to accelerating efforts in biodiversity conservation.
The three companies believe that biodiversity in the “cities” where we live every day, not just nature reserves and satoyama environments, is important from the perspective of residents’ well-being, and they are proposing unique town and garden development that focuses on native tree species. Asahi Kasei Homes has implemented “Machimori,” which aims to contribute to the streetscape and create small forests in cities by planting trees of various heights (hierarchical structure), Sekisui House’s “Five Trees” plan involves planting mainly native tree species suited to the local climate and environment with consideration for the ecosystem, and Daiwa House Industry is working on greening activities based on the concept of “Let’s connect greenery!”, which considers the local ecosystem network by planting more than 50% native species in real estate for various uses.
This time, by visualizing and integrating data on the number and species of trees from the three companies in the greater Tokyo area (Tokyo, Saitama, Chiba, and Kanagawa), the effects of the three companies’ different initiatives on urban biodiversity conservation were analyzed*3.
1) The three companies have planted a variety of tree species with different characteristics, which has resulted in greater biodiversity than if each company was on its own.
This analysis found that the three companies have planted a variety of different tree species through their respective initiatives, which has resulted in greater biodiversity than if they were each on an individual basis.
When the number of trees of each species planted by the three companies was examined, it was found that if the total tree species planted by the three companies was combined, it came to approximately 350 species and 430,000 trees per year, which was approximately 10% more species than the individual company with the largest number of species. This confirmed the importance of the greening activities of the three companies in urban areas and their great potential for nature positive effects.
Furthermore, when this data was plotted on a “species ranking curve relating to population numbers*4,” which shows the number of species and the level of evenness of species, and serves as an index of biodiversity assessment, the graph combining the three companies showed a gentler slope compared to each individual company, clearly indicating that various species coexist and that there is a rich diversity in planted tree species.
2) Each company will plant trees based on its own unique concept, effectively restoring multiple elements of biodiversity.
In an analysis by Think Nature Co., Ltd., the three companies’ different concepts for planting proposals focusing on native tree species were evaluated as having scientific significance, as they complement the multifaceted elements of biodiversity and effectively contribute to achieving nature positivity.
Asahi Kasei Homes’ “Machimori” provides habitats for birds and other creatures for whom hiding places and space are important, Sekisui House’s “Gohon no Ki” plan provides food resources for creatures, and Daiwa House Industry’s greening activities based on the concept of “Let’s Connect Green!” regenerate the habitats of creatures not only in residential areas but also in the surrounding areas. It was found that each has different elements necessary for biodiversity, resulting in multifaceted regeneration. It is expected that the regenerated urban green spaces will lead to the regeneration of further connections between creatures (food webs).
This collaborative demonstration by the three companies demonstrated synergy in effectively restoring the multiple elements of biodiversity by promoting planting proposals that focused on native species based on each company’s own greening concept, suggesting the possibility of co-creation between companies to achieve nature positivity.
In response to these results, Asahi Kasei Homes, Sekisui House, and Daiwa House Industry will work together to expand the initiative to the housing and real estate industries, so that more companies and organizations will support efforts centered on native tree species and further increase the effectiveness of Nature Positive.
Comment from Yasuhiro Kubota, Professor at the Faculty of Science, University of the Ryukyus and CEO of Think Nature
Information on the planting business of real estate and house manufacturers, i.e. “When, where, what type and how many trees were planted?” can be considered “greening accounting.” This three-company integrated analysis is a data analysis related to greening accounting, and quantitatively evaluates the “degree of contribution to biodiversity restoration” brought about by greening business assets. This analysis project is the first case in the world where visualizing the nature-positive effects of multiple companies’ planting businesses can serve as a social signal. We hope that this will encourage collective action involving more companies and contribute to Target 12 of the Kunming-Montreal Biodiversity Framework, “Ensuring urban green spaces and waterfront spaces.” At the same time, we hope that biodiversity will become a new value standard in the real estate and housing construction business, and that in the context of urban nature positivity, the industry as a whole will be able to add high value and create new business opportunities.
About Asahi Kasei Homes’ “Machimori”
“Machimori” is a unique planting method developed for residential exterior planning, utilizing knowledge of vegetation gained from “Asahi Forest of Life,” which has been underway since 2007 on the former factory site of a branch of Asahi Kasei Corporation in Fuji City, Shizuoka Prefecture. By combining plants of different heights – tall trees, medium-sized trees, shrubs, and ground cover plants – and planting them on the façade side, the aim is to contribute to a rich streetscape and attract a variety of creatures such as birds and insects. By connecting homes and apartment buildings equipped with “Machimori” to greenery such as roadside trees and parks in the city, a richer ecosystem is fostered, forming an “ecological network” for the entire region and promoting activities to conserve biodiversity in the city.
Town and Forest: A greener life is kinder to animals
■ About Sekisui House’s “Five Trees” Project
The “Five Trees” project was started in 2001 by our company as a biodiversity conservation initiative with the cooperation of our customers, as a landscaping and greening business that takes ecosystems into consideration. With the idea of ”three trees for birds, two for butterflies,” we propose garden and town development centered on native tree species suited to the climate and environment of the region. Since the start of the project, we have planted a cumulative total of 20 million trees.
In 2021, we developed the world’s first quantitative assessment system for urban biodiversity, using data on tree numbers, species, and locations as well as biodiversity big data to evaluate the effectiveness of biodiversity conservation, and released it as the “Nature Positive Methodology.”
Sekisui House’s “Five Trees” project
In anticipation of 2055, which will be our 100th anniversary, we set out our long-term environmental vision “Challenge ZERO 2055” in fiscal 2016, aiming to realize a sustainable society. In fiscal 2022, we will formulate specific plans and goals as the “Endless Green Program 2026” and are also working on biodiversity. As part of this, we are promoting greening activities that adopt more than 50% native species under the group-wide greening concept “Let’s connect the greenery!” to achieve nature positivity, and between April 2022 and March 2024, we have created a green area of 464,000 m2 (about 9 Tokyo Domes) that takes into consideration the local ecosystem.
Daiwa House Industry’s efforts to achieve nature positive (released August 19, 2024)
■Think Nature Co., Ltd.
We are a startup from the University of the Ryukyus, composed of researchers with outstanding achievements in biodiversity science. We support the nature-related businesses of various companies through advanced analysis using distribution data of over 300,000 species of organisms covering the world’s land and sea, and over 150 indicators related to biodiversity and natural capital. We leverage our unique strengths as experts in biology and ecology to help companies reduce nature-related risks, increase positive impacts, and shift to nature-positive management.
*1 Nature positive refers to halting and reversing biodiversity loss and putting it on a path to recovery.
*2 According to research by Asahi Kasei Homes, Sekisui House, and Daiwa House Industry
*3 A service that quantifies the nature positive effects that corporate activities have on nature through a scientific approach using AI and big data. )
*4 The “species ranking curve for population size” indicates the order of the proportion of the population of dominant, common, and rare species, and is a quantitative indicator of biodiversity. Species diversity can be evaluated by species richness (number of species) and evenness (evenness of the number of each species in the community). The more species there are and the more evenly they are distributed, rather than being biased toward certain species, the higher the species diversity. In the species ranking graph, the horizontal axis shows the species ranking counted from the species with the largest number of individuals, and the vertical axis shows the proportion of the species’ population to the total number of individuals. The more “simple the community” is, where the proportion of certain species in the community is large and where dominant species are prominent, the steeper the slope of the species ranking graph. On the other hand, in a “community rich in biodiversity” where various species coexist, the slope of the species ranking graph is gentler. In this graph, the red symbols and lines show the ranking curve of planted tree species that combines the plantings of three companies, and the yellow, green, and light blue show the ranking curves of tree species planted by each company. Compared to the slope of the graph ranking tree species planted by each individual company, the slope of the graph ranking species for the three companies combined is gentler, making it clear that there is a rich diversity in planted tree species.
Related links
Town and Forest: A greener life is kinder to animals
Sekisui House’s “Five Trees” project
Daiwa House Industry’s efforts to achieve nature positive (released August 19, 2024)
Source: Japanese