INNOVATION WITH A WATERING CAN

ARCHITECTS WORKING IN THE NEW FIELD OF “CONSTRUCTION BOTANY” ARE USING TREES TO CREATE LIVING STRUCTURES.

People often ask the Stuttgart-based architect Ferdinand Ludwig whether as a boy he played in tree houses. Or whether Tarzan was his hero. In both cases he has to pass: “No, I didn’t have a tree house, and I only became interested in Tarzan after people started asking me about him on account of my work.” This late summer day finds Ferdinand Ludwig, 31, blonde haired, with a three-day stubble, sneakers and a hoodie, standing amid the churned-up ground in the little Black Forest town of Nagold. The noise of construction machines surrounds him. Workmen are laying paths and lawns. Ludwig casts a critical eye over a curious object: a steel framework in the shape of a ten-meter cube, the struts and braces of which are concealed by young trees. In 2012 the “plane tree cube” is scheduled to be an attraction at the regional horticultural show, after which it will become the green centerpiece of a new neighborhood.

A BUILDING THAT GROWS
A few days prior to Ludwig’s inspection, landscape gardeners installed 200 tubs, each of which contained four plane trees as thick as a thumb, on the side walls of the cube. The saplings are bolted together in approximately 3,000 places. Over time they will grow together to become one organism, transmitting water and nutrients from soil to crown. It will then be possible to gradually remove the tubs from the walls. In 15 to 20 years the plants will encase the steel firmly enough to create a self-supporting structure.

BRIDGES FROM AERIAL ROOTS
For years now, Ferdinand Ludwig and his colleagues Oliver Storz and Hannes Schwertfeger of the Institute of Modern Architecture and Design (IGMA) at the University of Stuttgart have been working on load-bearing structures that utilize living trees—and in the process they have created a new architectural discipline known as “Construction Botany.” They tested the elasticity of various tree species, experimented with different lighting conditions, fertilization methods and connecting systems. They also studied traditional living structures: Bridges built in India using the aerial roots of rubber trees, and the lime trees once cultivated in Europe with branches so cunningly trained that boards could be laid out to create a dance floor in the crown of the tree. Years ago, in a marshy reed bed by Lake Constance, the group of young architects built a platform out of willows. The plants support the gratings of the footway and in many places now completely surround the steel handrails. They used the same technique—also in willow — to build a tower nearly nine meters tall with floors strong enough to walk on. Similar structures, including hides for bird-watching, were built in Waldkirchen in Bavaria, in Olfen in Westphalia, and in the experimental garden at the University of Freiburg.

MICRO GARDEN IN A TREE
In Ferdinand Ludwig’s words, the plane tree cube in Nagold is “the first construction botanic design for an urban context.” After the horticultural show, some townhouses equal in height to the cube are scheduled to be built close by, and over the years the cube itself will become an accessible, three-dimensional park. If the crowns of the plane trees grow well and reach further and further out towards the houses, Ferdinand Ludwig believes that the apartments on the upper floors could actually be extended into the crowns of the trees: “Because of the load-bearing characteristics, large floor areas would be impossible, but small rooms—a guest room, office, studio or a micro garden—would be technically feasible.” The ideas of Arthur Wiechula who in the 1920s imagined entire houses grown out of trees were certainly an inspiration to Ferdinand Ludwig. However, they are light years away from his wholly pragmatic thinking. “‘Construction Botany’ is not intended to replace steel or timber construction; it is an interface that draws on garden and landscape architecture to create new kinds of useful building structures.”

TARZAN WAS NO GARDENER
Ludwig is interested less in visions than in feasible innovations: He goes into raptures about a new type of bolt with a special head that makes joining the plants even more costeffective. One of the issues he addressed for his doctorate was how to train young plants to make them suitable for industrially prefabricated components for a maximum of potential applications. So it’s not surprising that Tarzan and tree houses leave him cold. “Tarzan wasn’t a gardener; he was a wild man who utilized the forest as he found it. As do builders of tree houses who use a minimum of technical artifice to make the tree habitable. Whereas Bau - botanik (Construction Botany) is just the opposite: We design and build a tree as an artificial organism.” The plane tree cube, Ludwig proudly explains, already has planning permission as a viewing platform. It even has an address: Goethestraße 4. Before the regional horticultural show opens in the spring of 2012, the architect intends to install a mail box—“Maybe we’ll get fan mail.”

Text: Stefan Scheytt, PhFotos: Cira Moro
Bilfinger Berger Magazine 1/2012