Trees Straighten Themselves With Wood That Works Like Opposing Muscles

After roughly ten days, once the trees had a noticeable curve, researchers moved them into the rotating apparatus. Over the following weeks, the stems slowly straightened until nearly straight again.

Wood analysis explained why. The original tension wood on the upper side stopped developing once the system was activated. Simultaneously, identical tension wood began forming on the opposite side, pulling in the other direction. The two forces worked against each other until the stem returned to straight.

That's the headline finding. Scientists previously believed tension wood formed only on a stem's upper side. The new work shows it can form on either side, generating force in either direction — much like the opposing muscle groups animals use for posture and movement. A tree's internal sense of its own shape regulates where this wood develops.

The takeaway: trees don't just react to gravity and light. They run a feedback system built on self-shape detection.

Why does this matter beyond botany?

The practical stakes are real. Storms, landslides and other extreme events bend or displace trees, and the ability to recover posture is central to resilience — a trait that matters more as climate change exposes forests to harsher conditions.

The applications branch in three directions:

• Forestry: selecting trees with especially effective proprioception could yield straighter trunks and higher-quality timber.
• Wood quality: poorly coordinated tension wood creates excessive internal stress that degrades the wood itself.
• Agriculture: the same knowledge could help breed cereal crops less prone to lodging — collapsing before harvest — which causes significant yield losses late in the season.

Moulia put it directly: "What we have uncovered is a genuine sensorimotor loop operating in the woody parts of trees! Poor coordination in the successive activation of tension wood results in excessive internal tension, which can affect wood quality. These findings therefore reshape more applied research aimed at improving wood quality... and at obtaining trees that are as straight and as relaxed as possible, whatever life throws at them!"

Hartmann credited the interdisciplinary team — researchers with complementary skills in biomechanics, wood anatomy and plant physiology — for the result. "Revealing the remarkable capabilities of trees requires a great deal of ingenuity," he said. "It requires time and perseverance, but these interdisciplinary discoveries show that the effort is worthwhile."

The bottom line: a tree's trunk carries its own muscle-like machinery, guided by a sense of self that science is only beginning to map.