Walls with Living Trees! First Development of a Tree-Type Wall Greening System in the Industry
Maintaining a long-term beautiful landscape of natural greenery with trees such as azaleas and dogwood! Also with the effect of cooling the surrounding atmosphere.

July 31, 2009
Takenaka Corporation

In addition to wall greening mainly using herbaceous species, Takenaka Corporation (President: Toichi Takenaka) has now developed a wall greening system which can also be used for trees. It is very difficult to maintain healthy trees on wall surfaces, which are extremely severe conditions for these plants, and safely attach them to the walls. With this newly-developed system, it is possible for the tree roots to freely extend throughout the entire plant panel, not just the individual panels. This means healthy trees can be maintained, providing a long-term beautiful green landscape. It is hoped that the greening through the picturesque growth of trees on the surface of walls will improve the city landscape, as well as work as a measure against heat- island phenomenon, which is one of the objectives of greening.
The safety and durability of the plant panels are maintained by producing them using fiber-reinforced cement. Because these plant panels can be individually installed and removed from the exterior wall, they can be used for new and existing buildings.

Depending on the types of plants and the work conditions, Takenaka is encouraging their use in buildings designed and constructed by the company, at around 150,000 yen per square meter (design price).

The appearance of wall greening in June 2009

[Features of the system]

1. The first beautiful tree landscaping using wall greening
Various types of small to medium-sized flowers and trees are kept healthy by allowing the roots to freely extend throughout the plant panel. Trees grow enough in about one year to hide the plant area of the panels, and flowers blossom. During the selection of trees, colorful variations can be enjoyed such as natural types, flowerbed types and hedge types. Also, unlike the conventional greening using herbaceous species, order-made green landscaping can be created according to the building design and the requirements of the client.

Plant examples:

needle-leaved trees (such as Japanese black pine, and Hiba), evergreens (such as Sasanqua, and Photinia fraseri or "Red Robin"), deciduous broad-leaved trees (such as Flowering Dogwood and Japanese maple), and shrubs (such as hydrangea and Thunberg's meadowsweer)

2. Long-term maintenance of high-quality green landscaping
By carrying out regular pruning and pesticide spraying, everlasting greening is possible. Compared to herbaceous species greening, the maintenance of greening using trees requires less pruning and weeding. By using automatic sprinkling, there is less watering maintenance required.

3. Environmental-load reduction effect
Because the rich transpiration effect of the trees reduces the surface temperature, the amount of heat transfer into the interior and amount of heating of the atmosphere is reduced, so energy savings and a relaxing of the heat-island phenomenon can be expected.

4. Installation possible for a wide range of walls, including existing walls
This greening system can be used for various types of building exterior walls, boundary walls, the retaining walls of civil engineering structures, and the temporary enclosure walls at construction sites.

[Outline of the system]

Plant panel

1. Plant panels
The plant panels have a four-layer structure: a plant-pot surface panel made using fiber-reinforced cement; a heat-insulation board; a middle-layer nonwoven fabric base board for water retention, drainage, ventilation, and fertilizer retention; and, a recycling board.
(Patent pending number 2007-080305)
Because the surface panels are made using fiber-reinforced cement with excellent safety durability properties, there is no need for concern of them coming off in the case of being hit by something or strong winds. The installation is a dry construction method, so no mess is made at the work site. The number of the panels can be freely adjusted depending on the wall area.

◇Panel size: 60cm x 90cm x 70cm (width x height x depth)
◇Weight: about 45kg per panel

2. Water sprinkling control
Water sprinkling is carried out using a drip hose installed at the top of the panels, and the amount and frequency of annual sprinkling is set using a control board. Liquid fertilizer can be diluted into the water sprinkling tank for an appropriate supply of fertilization.

[Test and case studies]

Verification tests carried out in 2006 confirmed healthy plant growth and the safety and durability of the plant panels.

July 2006 June 2007 May 2009

Account of the testing

• From July 2006
  Testing begun on a southern wall at the Takenaka Research & Development Institute
• From April 2007
  Testing also begun on a northern wall at the Takenaka Research & Development Institute
• August 2006
  The system used on the temporary enclosure walls at an environmental technology verification and testing facility in northern Kyushu
• July 2008
  Used on the walls of the "International Media Center" at the G8 Hokkaido Toyako Summit

[