The mechanical stability of the world’s tallest broadleaf trees
Toby Jackson, Alexander Shenkin, Noreen Majalap, Jamiluddin Bin Jami, Azlin Bin Sailim, Glen Reynolds, David A. Coomes, Chris J. Chandler, Doreen S. Boyd, Andy Burt, Phil Wilkes, Mathias Disney, Yadvinder Malhi
Abstract
Abstract The factors that limit the maximum height of trees, whether ecophysiological or mechanical, are the subject of longstanding debate. Here, we examine the role of mechanical stability in limiting tree height and focus on trees from the tallest tropical forests on Earth, in Sabah, Malaysian Borneo, including the recently discovered tallest tropical tree, a 100.8 m Shorea faguetiana named Menara. We use terrestrial laser scans, in situ strain gauge data and finite element simulations, to map the architecture of tall tropical trees and monitor their response to wind loading. We demonstrate that a tree's risk of breaking due to gravity or self‐weight decreases with tree height and is much more strongly affected by tree architecture than by material properties. In contrast, wind damage risk increases with tree height despite the larger diameters of tall trees, resulting in a U‐shaped curve of mechanical risk with tree height. Our results suggest that the relative rarity of extreme wind speeds in north Borneo may be the reason it is home to the tallest trees in the tropics. Abstract in MALAY is available with online material.