Trees are known for their great, but not unlimited, trunk height and diameter.
Trees are known for their great, but not unlimited, trunk height and diameter. They have evolved to develop a heavy above-ground biomass, but this integral feature poses a challenge to the trunk’s stability. Despite its evident importance, the principle by which plant stems respond to their increasing weight remains unknown. To address this question, a theory of “vertical proprioception”, a mechanism that balances the radial growth of the stem with the weight increase, has been developed.
To study the theory, researchers at the University of Helsinki, University of Cambridge and Natural Resources Institute Finland manipulated the aerial weight of downy birch (Betula pubescens). The authors observed that the tree was indeed able to adjust its stem radial growth in response to the added weight, and the strength of this response varied along the length of the stem. Furthermore, a degree of lateral stem movement was required for this response: static trees did not grow as thick as free-moving ones.
“Even though the idea of plants sensing their own weight and thickening their stem accordingly sounds intuitive, our study is the first one to address this question in trees”, says Juan Alonso-Serra from the Faculty of Biological and Environmental Sciences.
Read more at University of Helsinki
Photo credit: Picography via Pixabay
