Tree biomechanics.

Abstract

This review of tree biomechanics covers recent research publications that offer new insights into how trees respond to mechanical loads and resist failure, especially in winds. Biomechanical studies using dynamic rather than static structural methods are showing that the form of the tree influences dynamic response in winds and differences in tree morphology can produce extreme behaviours such as very little or nearly critical dissipation of stem oscillations. Biomechanical studies on trees that measure the forces, stresses and strains are reviewed including a new method of optical strain measurement where small dots (speckle) sprayed on tree surfaces show the strain distribution of trunks and branches under load. The role of stress and strain in tree growth is currently an important research question and the review includes papers that are indicating that strain may be the factor, more than stress, in triggering adaptive growth response. The importance of the form of trees influencing their wind loading is leading to investigations of the importance of branches, especially in winds where they act like coupled oscillators attached to an oscillating trunk to modify sway behaviour. Branch unions are being studied and new concepts on their attachment are also reviewed. Collectively, these developments are leading to a better understanding of tree biomechanics and the complex dynamic response of trees in wind.

Can Mechanical Strain and Aspect Ratio Be Used to Determine Codominant Unions in Red Maple without Included Bark

“…Branches become more rigid as they grow, and their primary function shifts away from sun branches with photosynthetic tissue to structural branches that hold smaller sun branches [47,[51][52][53][54]. As branch diameter increases, strain induced during bending should also increase, as strain increases with the distance from the pith [5,26,55,56]. We did not test the material properties of the wood in this study; as such, we do not know of the wood in the branch unions' proportion of juvenile to mature wood.…”

Vuelco del fique (Furcraea macrophylla) y sus repercusiones agronómicas

“…monocotiledónea, no cuenta con cambium vascular, que permite el engrosamiento del tallo y de la raíz para generar fuerzas estabilizadoras (James et al, 2017;Tanaka et al, 2012). Al poseer un sistema de raíz fasciculado, blando, poco lignificado y ramificado, las fuerzas que influyen sobre la planta hacen que el vuelco exceda sus límites biomecánicos (Yang et al, 2018).…”

Comparative study of flow field and drag coefficient of model and small natural trees in a wind tunnel

“…Moreover, predicting the dynamic response of a natural tree itself is a complex task due to the anisotropy in the material properties of the plant (James, 2017). The tree trunk wood of natural trees is known to have a radial anisotropy, resulting in a more complex mechanical response compared to isotropic materials (Albrecht et al, 2016).…”