Arbo-Architecture: Botany Building Treehouses

botany building
Three architects from Germany — Ferdinand Ludwig, Oliver Storz, and Hannes Schwertfeger — are experimenting with a new specialty they call “building botany.” The idea is to use fast growing trees to create a living structure to support buildings such as houses.

First, the architects build a conventional support structure. Young, flexible trees are attached to the structure and bent into the desired shape. As the trees grow, they take on more and more of a load-bearing function. After a few years — and what Ludwig calls a “botanical certificate of fitness” inspection by a structural engineer — the support structure can be removed. At which point the roof and floors that have been inserted should be supported entirely by the trees. (via Spiegel Online)

Some of the main points any treehouse builder can take away from this work:

1) Careful management of sap flow and bark integrity is essential to keep the trees alive. There is the “risk of strangulation” if metal fasteners used to bind the trunks obstruct the flow of sap. The architects have utilized a “sap bypass” method, using grafted in branches like heart bypass surgery, to route around choke points and keep the various parts of the structure alive.

2) It is necessary to stress the tree trunk with weights and changing forces so the trees sway in different directions and grow strong enough to become a structural support.

3) Stainless steel tubing is used to form a scaffold to define the shape of the building and provide a method for bending and forming the trees. Stainless steel, or galvanized steel, is a good choice because they will not rust nor poison the tree itself. The tubes are often enveloped into the trees and become enmeshed into the living structure. Once the trees have become strong enough to support the structure on their own, the steel tube scaffold can be removed and only the trees remain as the sole load bearing structure.

4) Trees such as Basket Willows are preferred for their speed of growth and flexibility to bend into various shapes. Willows are also robust enough to readily permit grafting, or “welding” the trees together, to merge to become a single organism.

I think that the integration of trees into the actual building structure is an unusual approach, and it does require a lot of extra time and planning. And there is also the issue of extra work in ongoing care and attention. This form of building a home is similar to maintaining an ornamental garden — constant meticulous maintenance is required “or else everything turns back into shrubbery,” Ludwig says.

However, the elasticity and regenerative qualities of trees continues to make them a high-tech, renewable, and eco-friendly material of choice for innovative architectural design.

via Designboom, Spiegel Online, and Inhabitat