Bite-size Biomimicry: Bark
How does bark protect from the elements and create conditions conducive to life?
The outer covering of trees is crucial to their survival in a variety of drastically different habitats from the alpine forest to the desert.
The shape, texture, and chemistry of bark is evolved to have specific functions depending on the habitat of a tree species; such as temperature/sunlight protection, keeping moisture in, keeping fungus and infections out, and resisting wildfire. These functions are achieved through a multi-layer form. The phloem is directly underneath the bark (which itself is a series of layers) and carries sugars from the leaves to the rest of the tree. As phloem dies it is pushed outwards and becomes part of the bark layer. Many trees also have a cork cambium layer, which forms a major part of bark (sandwiched between the cork and phloem). Bark appearance will change throughout a tree’s life, and older trees will often have tougher/thicker bark than younger trees.
Bark also creates a micro-habitat for invertebrates who find food or shelter on their rough surface. This then attracts birds, small mammals and other animals, and contributes to the greater food web in the ecosystem.
My question for you: how can we translate these strategies to design material inspired by bark? For example: what if the sides of our buildings created micro-habitats that contributed to the ecosystem in which they exist?
Bonus fun facts: The Silver Birch has white bark that reflects sunlight and protects the tree from getting damaged by UV rays, Scots pine has sticky resin, and oak bark contains tannins — chemicals that taste off-putting and are also toxic in high doses (we use this chemical for tanning leather). Ficus trees can repair damage in their bark by the cells secreting a latex into the “wound”, which then hardens as it dries in the air.
Learn more about bark strategies on AskNature.
Watch my full TikTok video exploring bark here.
