For hundreds of years, the Khasi people of the Meghalayan mountains in north-eastern India have built bridges created with living plants by making use of natural growth processes. Roots of rubber trees are used in order to construct a living bridge that regrows constantly and outperforms wooden bridges which would rot away too quickly. Living plant constructions is inspired by this approach and aims at using living trees with all their biological services also for construction purposes in order to create living architecture. An essential feature of Baubotanik buildings is that they fundamentally change their general shape, appearance and spatial effect from season to season and over time. (Ludwig 2015). 

Basic information

Type: 
Retrofitting + Creation

Performance

Evapotranspiration 1 1
Shading 2 none
Reflection (Albedo) none
Water Conveyance none
Water Infiltration none
Water Retention none
Water Storage none
Water Reuse none
Water Filtering none
Water Bio-remediation none
Deposition 1
Bio-filtration none
Habitat Provision 1
Connectivity 1
Beauty / Appearance 1
Usability / Functionality 1
Social Interaction 1
Role of Nature / Mode of Action: 
Living plant constructions use the natural process of inosculation, a process that can occur in nature when trunks, roots, or branches in close proximity slowly fuse together. This process also known as approach grafting, can arise within a single tree or neighbouring trees of same or different species. Over time, as the limbs grow, they exert increasing pressure on each other, similar to the friction between two palms rubbed together. This causes the outer bark to slough off, exposing the inner tissue and allowing the vasculature of both trees to intermingle, in essence joining their lifeblood (Oommen 2015). Fig. 37: Principle sketch of plant addition (source: Ludwig.Schoenle) Plant addition is one application of Baubotanik: Only the lowest plants are put in the ground, all others are planted into special containers on a scaffolding or into living wall segments. The containers are fitted with an automated system, which continuously supplies them with water and nutrients and allows them to grow roots. As this network of plants develops, the roots embedded in the ground grow more vigorously than those placed in containers because the ground provides more root space, which plants can exploit for additional resources. Once the inosculations have developed, the artificially created plant structure can transport water and nutrients from the roots in the ground to the upmost leaves, and the roots of the container plants become obsolete. Gradually, these high-level roots can be cut off, the automated watering system can be removed and, finally, the living structure becomes self-sufficient. At the same time, the secondary growth in circumference increases the strength of the plant structure and eventually it becomes self-supporting so that the scaffolding, initially required to support the containers and young plants, can be removed. Ultimately, this approach entails a completely new understanding of plants: the plant is no longer seen as a single biological entity with a naturally determined development path (from sapling to tree), but rather as a living construction material, materiality or element that is fused with other living material and technical construction elements to form a unified whole. This process allows the creation of living buildings at the scale of a fully-grown tree in a comparatively short time, or – if seen from another perspective – it permits the construction of trees. The result is not only an amalgamation of the elements “house” and “tree” but also an integration of the processes of building and growing (Ludwig 2015).
Technical & Design Parameters: 
Living plant construction can be implemented on any site, also on top of buildings. For the upper containers of the plants supporting structure is needed that either has a function in itself (e.g. staircase), is a living wall (example Green Living Room), or a separate structure.
Conditions for Implementation: 
Due to regulations living plant construction may need special building permissions for implementation
Benefits & Limitations: 
Benefits: The performance that adult trees deliver after decades can be achieved within a couple of years by living plant construction. Depending on the implementation living plant constructions serve as green facades or three dimensional open spaces and deliver respective services like heat reduction for buildings, shading for people, cooling ambient temperature as well as improving the amenity value. Potential limitations/disservices: Living plant constructions have a certain demand for maintenance and NBS Technical Handbook - Part II Version June 2018 Chapter 3 - 18 supervision, also irrigation systems are essential in the initial phase. Retrofitting buildings with living plant constructions is fairly difficult, for new constructions all required elements (supporting structures, access etc.) can be integrated right from the beginning. A Standardized procedure for building and maintaining needs to be developed.

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 730052 Topic: SCC-2-2016-2017: Smart Cities and Communities Nature based solutions