Scientists discover the hidden “muscles” trees use to straighten themselves
Scientists have discovered that trees can sense their own shape and straighten their trunks using specialized wood that acts like opposing muscles. This remarkable ability helps trees maintain their posture and could lead to stronger forests, better timber, and more resilient crops.
Key points
- Researchers isolated trees' internal sense of shape by rotating them horizontally in evenly lit spheres.
- Tension wood on opposite sides of stems acted like opposing muscles to straighten curved poplars.
- The findings could help breed straighter trees and crops less prone to lodging.
Scientists have identified how trees use a specialized wood to correct their posture, according to research from INRAE, the National Research Institute for Agriculture, Food and Environment. The study shows that trees can sense their own shape and adjust growth to straighten themselves, a capability once thought to exist only in animals.
The team isolated this internal sense, known as proprioception, by placing young poplar trees on a horizontal platform that rotated inside a sphere lit evenly from all directions. This setup removed consistent signals from gravity and light, allowing researchers to observe how trees respond to their own shape alone.
How tension wood works
The trees began horizontally and curved upward as they grew, using tension wood that forms on the upper side of stems and pulls them upward like a contracting muscle. After about ten days, researchers moved the curved trees into the rotating apparatus.
Over the following weeks, the stems slowly straightened. The original tension wood stopped developing, while identical tension wood began forming on the opposite side, producing an opposing pulling force that returned the stems to a nearly straight shape.
What we have uncovered is a genuine sensorimotor loop operating in the woody parts of trees!
— INRAE researchers
Practical implications
The research indicates tension wood can develop on opposing sides of a stem and generate forces in different directions, functioning like opposing muscle groups. This suggests trees combine environmental signals with internal shape awareness to regulate where the wood forms.
The findings could help forestry select trees that grow straighter and produce higher-quality wood, and help agriculture develop cereal crops less likely to fall over before harvest. The research also notes that poorly coordinated tension wood formation can create excessive internal stresses affecting wood properties.
