The motion of trees in the wind is related to wind damage risk and surface-atmosphere energy exchange. We collated all tree motion data and summarized the main patterns. We confirmed that the fundamental frequency of tree sway is related to tree height. We found that the motion of trees in conifer forests, the most studied system, is somewhat distinct from that of open-grown trees and broadleaf forests. We also found that no additional damping or amplification process emerge at high wind speeds.
The motion of trees in the wind is related to wind damage risk and surface-atmosphere energy...
Review status: this preprint is currently under review for the journal BG.
The motion of trees in the wind: a data synthesis
Toby D. Jackson1,Sarab Sethi2,Ebba Dellwik3,Nikolas Angelou3,Amanda Bunce4,Tim van Emmerik5,Marine Duperat6,Jean-Claude Ruel6,Axel Wellpott7,Skip Van Bloem8,Alexis Achim9,Brian Kane10,Dominick M. Ciruzzi11,Steven P. Loheide II11,Ken James12,Daniel Burcham13,John Moore14,Dirk Schindler15,Sven Kolbe15,Kilian Wiegmann16,Mark Rudnicki17,Victor J. Lieffers18,John Selker19,Andrew V. Gougherty20,Tim Newson21,Andrew Koeser22,23,Jason Miesbauer24,Roger Samelson25,Jim Wagner26,David Coomes1,and Barry Gardiner27Toby D. Jackson et al.Toby D. Jackson1,Sarab Sethi2,Ebba Dellwik3,Nikolas Angelou3,Amanda Bunce4,Tim van Emmerik5,Marine Duperat6,Jean-Claude Ruel6,Axel Wellpott7,Skip Van Bloem8,Alexis Achim9,Brian Kane10,Dominick M. Ciruzzi11,Steven P. Loheide II11,Ken James12,Daniel Burcham13,John Moore14,Dirk Schindler15,Sven Kolbe15,Kilian Wiegmann16,Mark Rudnicki17,Victor J. Lieffers18,John Selker19,Andrew V. Gougherty20,Tim Newson21,Andrew Koeser22,23,Jason Miesbauer24,Roger Samelson25,Jim Wagner26,David Coomes1,and Barry Gardiner27
Received: 16 Nov 2020 – Accepted for review: 23 Dec 2020 – Discussion started: 28 Dec 2020
Abstract. 1. Interactions between wind and trees control energy exchanges between the atmosphere and forest canopies. This energy exchange can lead to the widespread damage of trees and wind is a key disturbance agent in many of the world’s forests. However, most research on this topic has focused on conifer plantations, where risk management is economically important, rather than broadleaf forests, which dominate the forest carbon cycle. This study brings together all available tree motion time-series data to systematically evaluate the factors influencing tree responses to wind loading, including data from both broadleaf and coniferous trees in forests and open environments.
2. We found that the two most descriptive features of tree motion were: (a) the fundamental frequency, which is a measure of the speed at which a tree sways and is strongly related to tree height, and (b) the slope of the power spectrum, which is related to the efficiency of energy transfer from wind to trees. Intriguingly, the slope of the power spectrum was found to remain constant from medium to high wind speeds for all trees in this study. This suggests that, contrary to some predictions, damping or amplification mechanisms do not change dramatically at high wind speeds and therefore wind damage risk is related, relatively simply, to wind speed.
3. Conifers from forests were distinct from broadleaves in terms of their response to wind loading. Specifically, the fundamental frequency of forest conifers was related to their size according to the cantilever beam model (i.e. vertically distributed mass), whereas broadleaves were better approximated by the simple pendulum model (i.e. dominated by the crown). Forest conifers also had a steeper slope of the power spectrum. We interpret these finding as being strongly related to tree architecture, i.e. conifers generally have a simple shape due to their apical dominance, whereas broadleaves exhibit a much wider range of architectures with more dominant crowns.
The motion of trees in the wind is related to wind damage risk and surface-atmosphere energy exchange. We collated all tree motion data and summarized the main patterns. We confirmed that the fundamental frequency of tree sway is related to tree height. We found that the motion of trees in conifer forests, the most studied system, is somewhat distinct from that of open-grown trees and broadleaf forests. We also found that no additional damping or amplification process emerge at high wind speeds.
The motion of trees in the wind is related to wind damage risk and surface-atmosphere energy...