In:
Biogeosciences, Copernicus GmbH, Vol. 18, No. 13 ( 2021-07-06), p. 4059-4072
Abstract:
Abstract. 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 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. 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. 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.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-18-4059-2021
DOI:
10.5194/bg-18-4059-2021-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2021
detail.hit.zdb_id:
2158181-2
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