Coexistence with nature (biodiversity)

“Living in harmony with Nature” has been positioned at the beginning of Vision 2050 for the global goals of the Kunming-Montreal Global Biodiversity Framework as well as the National Biodiversity Strategy of Japan 2023-2030. In order to achieve this, Biodiversity Conservation and Restoration (Nature Positive) was added to the Kunming-Montreal mission as a short-term goal (2030 Mission). Conserving rich biodiversity and realizing a society in harmony with nature that can enjoy its blessings in the future is an important social issue, both for realizing a sustainable society and for making our business sustainable. Capitalizing on our deep knowledge and problem-solving capabilities related to the conservation and restoration of biodiversity, Takenaka Corporation is committed to realizing a society in harmony with nature that can enjoy its blessings into the future.

In our Environmental Concept Book, which was published in 2021, Takenaka Corporation has established targets for 2023 by embracing the realization of a society in harmony with nature as one of the perspectives of a long-term road map to reach the society we aspire to in 2050, and then by performing back casting from 2050. We also assume that new social systems and technological innovations will be required to achieve these goals. Our road map focuses on green infrastructure as an important technological approach to achieving a society in harmony with nature, and we will present our efforts in the following chapters.
In order to take specific action on biodiversity, we established Biodiversity Action Guidelines in 2012, and then launched a variety of initiatives.

The benefits of biodiversity (ecosystem services) comprise a form of “natural capital” at the foundation of sustainable economies and societies. In order to realize a society where people and nature coexist in harmony, we will promote urban development that introduces green infrastructure to make use of the diverse functions of nature for multiple purposes with the aim of improving biodiversity.

(Environment) A city that coexists with nature while minimizing environmental impacts
(Economy) An appealing city that attracts human resources
(Society) A city where all residents can live comfortably and participate socially
(Disaster prevention and mitigation) A safe, secure, disaster-resilient city
(Health) A city where people can enjoy physical and mental health, as well as peace of mind

Rainscape contributes to biodiversity conservation during normal weather, while allowing for the storage and infiltration of rainwater during heavy rainfall, thereby reducing peak rainwater runoff. It also promotes effective water use and refills groundwater. This decentralized watershed technology allows for rainwater storage and infiltration at individual sites as a countermeasure to heavy rain-induced flooding seen in recent years. A green infrastructure component, it contributes to the restoration of a healthy water cycle and the creation of greenery rich communities. SHI-RA-BE Rainscape increases water storage and infiltration by providing adjacent ecological pond capacity adjustments as well as topography specifications.
During one heavy rainfall event in October 2019 when precipitation totaled some 248mm in just 24 hours, 236 cubic meters of water--equivalent to about 43 percent of the total precipitation in the catchment area--was stored and infiltrated into the Rainscape area alone, thereby reducing the runoff load on the sewer system.

Currently, the majority of the world's population is concentrated in cities, which depend on the benefits (ecosystem services) provided by biodiversity. Urban socioeconomic activities are believed to be the cause of much of the world's accelerating biodiversity degradation. In order to achieve the 17 Sustainable Development Goals (SDGs) unanimously adopted at the 2015 United Nations Summit, the goals of natural capital, or biodiversity conservation, are common around the world. They form the basis of the UN’s 17 social and economic goals. As an integrated engineering firm for urban creation, the Takenaka Group has been promoting the Takenaka Biodiversity Promotion Program, which embodies Guidelines for Biodiversity Activities, and is consistent with our growth strategy. Through this program, we aim to enhance our ability to resolve social issues, including biodiversity conservation, and contribute to the realization of a sustainable society. This section introduces our Seiwadai Forest activity--our approach to natural capital that supports the UN’s SDGs. This, in turn, is based on the above-mentioned Seiwadai Forest site at the Takenaka Training Center located in Kawanishi City, Hyogo Prefecture in western Japan.

The Takenaka Group has been an industry pioneer in environmental initiatives. Our efforts began with the motto “Green in Design” (1971), followed by our Environmental Charter (1992), Environmental Policy (2009), Environmental Message, “Connecting people with nature” (2010), and Biodiversity Action Guidelines (2012).

The Seiwadai Forest Project was launched in 2017 as a Takenaka Biodiversity Promotion Program that embodies our environmental policy and Biodiversity Action Guidelines.

Seiwadai Forest creates and implements a model for ecosystem and biodiversity conservation. Through it, we are engaged in the following four activities:

To promote these activities, Seiwadai Forest is being converted from an evergreen forest with no sunlight to a bright, biodiverse forest comprised mainly of deciduous trees. To this end, the Museum of Nature and Human Activities, Hyogo has been enlisted as an outside expert. At the start of the activities, the first step was to develop a “field center” and “nature observation paths” to serve as a base. In 2018, we also launched ② Hands-on training programs in order to learn from actual examples of satoyama habitat conservation and utilization.

The Hokusetsu region’s Kurokawa district, where Seiwadai Forest is located, is said to boast the best satoyama in Japan. Charcoal produced using kunugi (sawtooth oak) has been known by the names kikutan (chrysanthemum charcoal) or Ikeda-tan for more than 500 years, and it is valued as a high-grade charcoal used in traditional tea ceremonies. In the Kurokawa area, kunugi trees are culled in 10-year cycles to create a forest mosaic of various ages. The satoyama forests of red pine and konara oak can still be seen today. Learning from Japan's best satoyama, forestation training programs are used to develop the Seiwadai Forest Takenaka Training Center as a way to not only learn green space management techniques, but also to discover and refine skills that can contribute to society and the community. With Takenaka Group employees working together through elementary and intermediate training, the purpose is to develop next-generation leaders who can solve a wide range of social issues through the efforts of unified group employees.

Beginner training starts with a tour of the Kurokawa area. Participants visit a charcoal-making kiln that utilizes kunugi trees harvested from the satoyama. They also listen to a talk by Mr. Imanishi, a charcoal farmer, on producing high-grade kikutan. We realize the importance of continuing long-term care for satoyama in order to receive its bounty. The tour also stops at the Kawanishi Satoyama Club, a citizens' group active at nearby Mt. Myoken, and at the Nose Electric Railway Company, and observe the conservation activities for restoring the edohigan (prunus itosakura) flowering plant, a natural treasure of Kawanishi City. The following day, participants learn about the importance of satoyama management to protect biodiversity and the value of the Seiwadai Forest via a classroom lecture.

In intermediate level training, participants learn from experts about how to increase biodiversity, the necessity of trimming broad-leaf evergreens and culling trees that block sunlight in order to promote diverse plant growth. The woods are transformed into bright areas with clear visibility in about four hours. At the end of the training, a workshop is held to review the four days of beginner and intermediate level sessions, and discuss sustainability and how to utilize the Seiwadai-no-mori in the future. We are now considering how to develop many of the ideas presented at the workshop into specific measures.

From 2021, we have been nurturing the next generation of leaders to resolve social issues related to biodiversity, targeting graduates of the beginner and intermediate training courses that started in 2018. Largely based on workshop efforts, the program examines solutions from various angles that can actually be used in conserving and enhancing biodiversity. At the COP15 United Nations Biodiversity Conference held in December 2022, biodiversity initiatives were highlighted and became a global trend. Expectations are therefore high for the results of this training program.

Going forward, we will continue with Activity ②: Hands-on training while bolstering Activity ④: Cooperation and collaboration with stakeholders, and conduct Activity ①: Maintenance and conservation activities led by Takenaka Group employees. This will be linked to Activity ③: Research and development, and environmental technology development.” We will also apply knowledge gained through Seiwadai Forest to architectural works and community development in other areas. Currently, we are zoning Seiwadai Forest for conservation, maintenance, utilization, and developing a scenario for forest creation over the next 20 years. In particular, the vast grounds will be used as a new learning place where people can gather and gain new insights, for example by creating full-scale green space models and nursery plots for growing seedlings. We also expect that new business models will be generated through communication beyond departments and organizations. Natural capital is the social and economic base that supports cities. We will continue to treat biodiversity conservation (which supports natural capital) as our adopted initiative, and engage in hito-zukuri (people development) activities that foster the ability of individuals to take the lead in this forthcoming new era. At the same time, we will increase our friendships, have fun, and slowly but surely confront the complex, multifaceted mission of resolving local issues and engaging in urban creation.

In order to promote optimal land use that takes advantage of the diverse functions of nature through our projects, we focus on biodiversity, consideration of local vegetation, land use history, creating ecosystem networks, and efforts from planning and design to postconstruction maintenance and operation with all involved participants. These activities are being tracked and recorded.

We are creating a place where visitors can experience our activities to conserve and nurture watershed forests. We have teamed up with clients and specialists to understand the current vegetation and topography, using drone surveys and physical visits to determine the optimal parkway location where visitors can tour the site. Boulders once carried by the river were placed along the parkway and in the waterscape. The plan also utilizes the region’s natural landscape by harvesting and replanting seedlings from forests affected by land development, and by introducing local seeds and seedlings into the new planting area.

WITH HARAJUKU is a commercial complex that includes stores, a coworking hall, and a residential complex on a site that connects Harajuku Station and Takeshita-dori Avenue, and near Meiji Jingu Shrine, which is celebrating its 100th anniversary. The site has an eight-meter east-to-west elevation differential, and a new semioutdoor street space called the “Passage” in the building’s center that allows east-side Takeshita-dori Avenue passage. Along the Passage, a recreated Edo era green terraced hill called Genjiyama has been recast in the form of a staircase which overlooks Harajuku to the city. The exterior is clad in thick wood that echoes Meiji Shrine history and reveals an expression that has deepened over time.

ACROS Fukuoka was established in 1995 on the site of the former prefectural government office in Tenjin District in the heart of Fukuoka City. This public-private complex is based on the concept of a “center for international, cultural, and information exchange.” The building's most distinctive feature is the “step garden,” a staircase-like rooftop garden with an enjoyable view of Fukuoka City. The step garden, carefully nurtured over the 26 years since its completion through supplemental planting, has grown to yield a new ecosystem with an increasing number of tree species, including some that have grown naturally from seeds carried by wild birds. Called “Akurosu-yama” (ACROS Mountain) by local residents, it sports abundant greenery like a natural mountain. Together with the adjacent Tenjin Central Park, it is a space for relaxation. In addition, the step garden mitigates “heat island” effects, thereby contributing to global warming reduction.