SEKISUI HOUSE–KUMA LAB’s “Living Tree Furniture Prototype Research” project explored design methods that harness the unique characteristics of natural materials. The project aimed to create furniture prototypes using broadleaf trees that were scheduled for disposal after being cut down.
Unlike standardized lumber commonly available in the market, trees growing naturally in mountains or gardens have irregular shapes, making them difficult to process and utilize after being felled. As a result, many of these trees are left untouched or discarded without being fully utilized. In particular, small-diameter broadleaf trees with curved trunks have been considered extremely challenging to use for furniture or building materials due to the need to account for deformation after drying.
This project leverages digital technology in the design process, enabling accurate handling of complex shapes. By controlling the entire process from design to wood processing using computers, it accommodates variations in shape between different materials while simplifying joint design and assembly. The same processing and assembly methods can be applied to various types of wood with different shapes, allowing for the development of reproducible design techniques.
By incorporating digital technologies such as 3D scanning and CNC processing into the design process, the project expands the possibilities for utilizing various types of natural wood that were previously considered difficult to use, such as trees from neglected satoyama (managed woodlands) or trees with sentimental value scheduled for felling due to construction work.
1. Digital Wood Selection
3D scanning was performed on the trees scheduled for felling while they were still growing from the ground. The scans were then used to simulate wood selection on a computer. The scan data enables the examination of cutting methods tailored to the unique shape of each tree before felling. By exploring the variations of lumber obtainable from a single tree and the possibilities of various combinations, a lumber production plan was formulated. Rather than procuring materials based on desired shapes, the research began by delving into the potential forms that could be created from the available materials.
2. Diagonal Sawing of Curved Trees
Sawing machines are designed to saw sufficiently thick, straight lumber into uniform shapes, but they cannot efficiently saw the type of wood used in this project into consistent dimensions. By employing the simple operation of diagonal cutting, unique pieces of lumber with varying lengths and shapes were produced while making the most of the wood’s natural form.
*The sawing and drying processes were carried out in cooperation with a local lumber mill (Tamura Lumber).
3. 3D Scanning to Accommodate Deformation by Drying Shrinkage
During the drying process, wood undergoes deformation such as warping and twisting. It is well known that small-diameter broadleaf trees experience significant deformation, with the amount of deformation varying depending on individual differences and conditions. As it is difficult to accurately predict the deformation, the deformed wood was precisely 3D scanned using a high-performance handheld scanner to digitize the data.
4. Accurate Joint Processing Using CNC
Based on the scanned data, joint designs were examined. Aiming to facilitate repeated assembly and disassembly and enable the wood to be self-supporting without the use of metal fittings, the joints were designed without using any hardware. By accurately understanding the complex intersecting shapes of the wood and performing machining according to the data, all the parts were successfully processed by students without advanced woodworking skills.
5. Manual Assembly – Wood Supporting Each Other
The wood assembly was designed to be achievable using only manual labors. The basic unit structure relies on the heavy broadleaf wood pieces leaning against each other for support. Due to the weight and thickness of the wood itself, it exhibits sufficient strength when tightly interlocked. In the future, the plan is to incorporate elements such as weight and joint strength into the design process as calculable factors and to explore the possibility of combining the wood with other materials to increase the scale.
6. Prototypes
Furniture prototypes (tables and bench) were created using zelkova and cherry wood. From a single zelkova tree, bench-type and table-type products were prototyped, while the cherry wood was used to create an experimental composite-type furniture with a complex shape. In addition to 3D modeling studies, the final form was determined by physically handling the heavy wood, checking the strength and balance between the pieces, and fine-tuning the joint positions.
Future research plans include developing design methods that automate parts of the current process and conducting mechanical verifications to increase the scale. By exploring possibilities beyond standardized materials, the project aims to expand the potential of design while broadening perspectives on resources in a circular economy.
