Using tree forks as loadbearing joints
A team of MIT researchers developed a method that enables architects to use usually discarded tree forks as load-bearing joints in structures.
While wood is being increasingly used in construction, generally, only the straight parts are used. Irregular sections such as knots and forks (the part of the tree where a branch splits in two, creating a Y-shaped piece) are turned into pellets or ground up to make garden mulch.
In architectural drawings, there are many Y-shaped nodes where straight elements come together. In these cases, the units must be strong enough to support critical loads.
Tree forks are naturally engineered structural connections that work as cantilevers in trees. They can transfer force efficiently thanks to their complex internal fibre structure. According to the team, “the greatest value you can give to a material is to give it a load-bearing role in a structure”. Therefore, they developed a five-step ‘design-to-fabrication workflow’, which combines natural structures such as tree forks with the digital and computational tools now used in architectural design. These tools make it possible to used wood in structural roles, without excessive cutting which is costly and may compromise the natural geometry and the internal grain structure of the wood.
With their technology, the team made a temporary installation of 12 nodes. The structure is not complete yet due to the pandemic. the full structure will include 40 nodes, which will be installed as an outdoor pavilion.
In the future, the research will also include multibranch forks.
Photos: Felix Amtsberg / MIT