Adoption of “Vertical Forest” at the Ajinomoto Stadium

―Covering the walls of the stadium with trees native to the Musashino region―

August 1, 2012Takenaka Corporation

Takenaka Corporation (President: Toichi Takenaka) has developed the wall greening system called “Vertical Forest®,”which has been adopted as a technology to green 1,450 square meters of walls of the Ajinomoto Stadium (Nishimachi, Chofu City). “Vertical Forest®” is a wall greening method which makes full use of trees, a type of greening method rarely used anywhere in the world. It is a system capable of robustly nurturing trees to maintain beautiful green scenery for many years by allowing the roots of the trees to grow not only on individual planting panels, but freely over all the planting panels. Considering how its foliage expands, it can actually green 2,000 square meters of wall area.

Five patterns of planting panels were specially manufactured and installed like a jigsaw puzzle to prevent gaps in order to realize the concept of a design which does not alter the variously shaped windows and openings on the stadium wall. The trees selected for planting on the stadium were trees native to the Musashino Region.

Photo of the wall in July 2012

Project name Ajinomoto Stadium (22) first class athletics stadium renovation work
Client Tokyo Metropolitan Government
Location 376-3 Nishimachi, Chofu City, Tokyo
Number of floors 3 fl. aboveground
Design Nihon Sekkei, Inc.
Construction Taisei Corporation and Sakata-Construction Co., Ltd. (JV)
Use Sports stadium

This renovation work has been executed in order for the Ajinomoto Stadium, which will be a major venue for the Sports Festival in Tokyo 2013, to earn designation as a first class athletics stadium. The Ajinomoto Stadium West Sports Stadium was constructed on a site to the west of the main stadium as an auxiliary stadium (third class athletics stadium), necessary for the main stadium to earn designation as a first class athletics stadium.

Thermal effects of adopting the “Vertical Forest®”

The transpiration effects and the radiation environment improvement effects of the trees achieved by enclosing the stadium walls in greenery reduce the surface temperature of the greened walls, preventing the rise of the temperature of the stadium walls. It can also be counted on to prevent glare.

Concept of tree selection

The trees selected are thirty-two tree species including Chinese evergreen oak (Quercus myrsinaefolia), a type of laurel (Neolitsea sericea), and holly olive (Osmanthus heterophyllus), which are native to the Musashino Region where the Ajinomoto Stadium is located, and are suitable for the Musashino Forest, which will be formed in the future. Many are evergreens selected to ensure year-round greenery, while to add color, trees which flower in various seasons and broadleaved trees and other deciduous trees are also selected. To establish environments which are best suited for the growth of each of the 32 species, the most appropriate planting layout was implemented by deciding which tree species should be planted at each location.

Outline of the “Vertical Forest®”

A wall greening method which makes full use of trees, a type of greening method rarely used anywhere in the world, consists of planting panels which grow the vegetation, an automatic irrigationsystem, and planted trees. It robustly nurtures a variety of trees throughout the year to maintain green scenery with superior design qualities.

Configuration of the greening panels

Planting panels

In order to green the wall surface matched to the shapes of openings in the stadium, five kinds of planting panels are combined like the pieces of a jigsaw puzzle.

1. W690 x H900 x D(35+150)
2. W690 x H560 x D(35+150)
3. W623 x H900 x D(35+150)
4. W690 x H560 x D(35+150)
5. W623 x H900 x D(35+150)

Planting panels consist of four layers: surface panels with planting pots made of fiber reinforced cement, insulation boards, nonwoven fabric middle layers, which provide water retention, drainage, ventilation, and nutrient retention properties, and recycled board (patent application No.: 2007-080305). The surface panels provide superior safety and durability, so there is no danger of them being broken by impact or displaced by strong wind. They can be installed using a dry method, so the work does not soil the work area.

Irrigation control

The trees are irrigated automatically by drip hoses installed at the top of the panels. The system is divided into six sections around the periphery of the stadium, each of which automatically controls irrigation. The quantity and frequency of irrigation are set annually on a control board. The trees are fertilized by diluting and appropriately supplying liquid fertilizer with a liquid fertilizer mixer.

Master urban plan of Chofu City

The theme of the master urban plan enacted by Chofu City where the Ajinomoto Stadium is located is “Creating a place for people to mingle and relax by taking advantage of the natural life of the Musashino Forest and Tama River.” Then, based on this theme, “Preserving the natural environment and the historical and cultural environmental resources which survive in the region” and “Promoting creation of greenery through public – private sector cooperation” are goals set in the “Chofu City urban planning guidelines by district (developed and designed on March 31, 2010 (proposed)),” and the district is one where “preserving the features of Musashino and conserving its environmental resources” and “improving nearby parks and green belts” are promoted.

This renovation work is intended to link the greenery of the Ajinomoto Stadium and the auxiliary stadium to form the Musashino Forest, making Chofu City a city rich in greenery.