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Wang H, Hua J, Kang M, Wang X, Fan XR, Fourcaud T, de Reffye P. Stronger wind, smaller tree: Testing tree growth plasticity through a modeling approach. FRONTIERS IN PLANT SCIENCE 2022; 13:971690. [PMID: 36438108 PMCID: PMC9686872 DOI: 10.3389/fpls.2022.971690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 10/05/2022] [Indexed: 06/16/2023]
Abstract
Plants exhibit plasticity in response to various external conditions, characterized by changes in physiological and morphological features. Although being non-negligible, compared to the other environmental factors, the effect of wind on plant growth is less extensively studied, either experimentally or computationally. This study aims to propose a modeling approach that can simulate the impact of wind on plant growth, which brings a biomechanical feedback to growth and biomass distribution into a functional-structural plant model (FSPM). Tree reaction to the wind is simulated based on the hypothesis that plants tend to fit in the environment best. This is interpreted as an optimization problem of finding the best growth-regulation sink parameter giving the maximal plant fitness (usually seed weight, but expressed as plant biomass and size). To test this hypothesis in silico, a functional-structural plant model, which simulates both the primary and secondary growth of stems, is coupled with a biomechanical model which computes forces, moments of forces, and breakage location in stems caused by both wind and self-weight increment during plant growth. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) is adopted to maximize the multi-objective function (stem biomass and tree height) by determining the key parameter value controlling the biomass allocation to the secondary growth. The digital trees show considerable phenotypic plasticity under different wind speeds, whose behavior, as an emergent property, is in accordance with experimental results from works of literature: the height and leaf area of individual trees decreased with wind speed, and the diameter at the breast height (DBH) increased at low-speed wind but declined at higher-speed wind. Stronger wind results in a smaller tree. Such response of trees to the wind is realistically simulated, giving a deeper understanding of tree behavior. The result shows that the challenging task of modeling plant plasticity may be solved by optimizing the plant fitness function. Adding a biomechanical model enriches FSPMs and opens a wider application of plant models.
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Affiliation(s)
- Haoyu Wang
- The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- Beijing Engineering Research Center of Intelligent Systems and Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Jing Hua
- The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- Beijing Engineering Research Center of Intelligent Systems and Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Mengzhen Kang
- The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, China
| | - Xiujuan Wang
- The State Key Laboratory of Management and Control for Complex Systems, Institute of Automation, Chinese Academy of Sciences, Beijing, China
- Beijing Engineering Research Center of Intelligent Systems and Technology, Institute of Automation, Chinese Academy of Sciences, Beijing, China
| | - Xing-Rong Fan
- Engineering Research Centre for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Technology and Business University, Chongqing, China
| | - Thierry Fourcaud
- CIRAD, AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
| | - Philippe de Reffye
- CIRAD, AMAP, Univ Montpellier, CIRAD, CNRS, INRAE, IRD, Montpellier, France
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2
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Ojo O, Shoele K. Branching pattern of flexible trees for environmental load mitigation. BIOINSPIRATION & BIOMIMETICS 2022; 17:056003. [PMID: 35654029 DOI: 10.1088/1748-3190/ac759e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 06/01/2022] [Indexed: 06/15/2023]
Abstract
Wind-induced stress is the primary mechanical cause of tree failures. Among different factors, the branching mechanism plays a central role in the stress distribution and stability of trees in windstorms. A recent study showed that Leonardo da Vinci's original observation, stating that the total cross section of branches conserved across branching nodes is the optimal configuration for resisting wind-induced damage in rigid trees, is correct. However, the breaking risk and the optimal branching pattern of trees are also a function of their reconfiguration capabilities and the processes they employ to mitigate high wind-induced stress hotspots. In this study, using a numerical model of rigid and flexible branched trees, we explore the role of flexibility and branching patterns of trees in their reconfiguration and stress mitigation capabilities. We identify the robust optimal branching mechanism for an extensive range of tree flexibility. Our results show that the probability of a tree breaking at each branching level from the stem to terminal foliage strongly depends on the cross section changes in the branching nodes, the overall tree geometry, and the level of tree flexibility. Three response categories have been identified: the stress concentration in the main trunk, the uniform stress level through the tree's height, and substantial stress localization in the terminal branches. The reconfigurability of the tree determines the dominant response mode. The results suggest a very similar optimal branching law for both flexible and rigid trees wherein uniform stress distribution occurs throughout the tree's height. An exception is the very flexible branched plants in which the optimal branching pattern deviates from this prediction and is strongly affected by the reconfigurability of the tree.
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Affiliation(s)
- Oluwafemi Ojo
- Department of Mechanical Engineering, Joint College of Engineering, Florida A&M University-Florida State University, Tallahassee, FL, United States of America
| | - Kourosh Shoele
- Department of Mechanical Engineering, Joint College of Engineering, Florida A&M University-Florida State University, Tallahassee, FL, United States of America
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3
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Exploring the mechanical and morphological rationality of tree branch structure based on 3D point cloud analysis and the finite element method. Sci Rep 2022; 12:4054. [PMID: 35260741 PMCID: PMC8904476 DOI: 10.1038/s41598-022-08030-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
Trees are thought to have acquired a mechanically optimized shape through evolution, but a scientific methodology to investigate the mechanical rationality of tree morphology remains to be established. The aim of this study was to develop a new method for 3D reconstruction of actual tree shape and to establish a theoretical formulation for elucidating the structure and function of tree branches. We obtained 3D point cloud data of tree shape of Japanese zelkova (Zelkova serrata) and Japanese larch (Larix kaempferi) using the NavVis Lidar scanner, then applied a cylinder structure extraction from point cloud data with error estimation. We then formulated the mechanical stress of branches under gravity using the elastic theory, and performed finite element method simulations to evaluate the mechanical characteristics. Subsequently, we constructed a mechanics-based theoretical formulation of branch development that ensures constant bending stress produces various branching patterns depending on growth properties. The derived theory recapitulates the trade-off among branch growth anisotropy, stress-gravity length, and branch shape, which may open the quantitative way to evaluate mechanical and morphological rationality of tree branches.
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4
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Li HH, Cheng YC, Yang KJ, Chu CR, Hong TM. Role of the crown in tree resistance against high winds. Phys Rev E 2021; 104:025006. [PMID: 34525538 DOI: 10.1103/physreve.104.025006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 07/28/2021] [Indexed: 11/07/2022]
Abstract
Rather than using wooden sticks to simulate the breakage of trees in high winds as in most research, we employ fresh samples from camphor and Formosa gum with branches and leaves to certify the crucial role of the tree crown. By using a blowdown wind tunnel with a maximum wind speed of 50 m/s, we purposely reduce the number of leaves and show that the drag force will drop by as much as two thirds when half pruned. Based on real observations, we model the leaf by an open and full cone in the presence of light and strong winds, and calculate how their corresponding cross-sectional area A and drag force F vary with wind speed v. Different slopes before and after the formation of a full cone are predicted and confirmed when these two quantities are plotted in full-log scale. Compared to the empirical value, our simple model gave α=2/5 and 2/3 for A∝v^{-α} and β=4/5 and 2/3 for F∝v^{β} at low and high winds. Discrepancies can be accounted for by including further details, such as the reorientation of open cones and the movement of branches.
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Affiliation(s)
- Hsin-Huei Li
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Yu-Chuan Cheng
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
| | - Kai-Jie Yang
- Department of Civil Engineering, National Central University, Taoyuan, Taiwan 32001, Republic of China
| | - Chia-Ren Chu
- Department of Civil Engineering, National Central University, Taoyuan, Taiwan 32001, Republic of China
| | - Tzay-Ming Hong
- Department of Physics, National Tsing Hua University, Hsinchu, Taiwan 30043, Republic of China
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5
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Brummer AB, Lymperopoulos P, Shen J, Tekin E, Bentley LP, Buzzard V, Gray A, Oliveras I, Enquist BJ, Savage VM. Branching principles of animal and plant networks identified by combining extensive data, machine learning and modelling. J R Soc Interface 2021; 18:20200624. [PMID: 33402023 PMCID: PMC7879751 DOI: 10.1098/rsif.2020.0624] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Branching in vascular networks and in overall organismic form is one of the most common and ancient features of multicellular plants, fungi and animals. By combining machine-learning techniques with new theory that relates vascular form to metabolic function, we enable novel classification of diverse branching networks—mouse lung, human head and torso, angiosperm and gymnosperm plants. We find that ratios of limb radii—which dictate essential biologic functions related to resource transport and supply—are best at distinguishing branching networks. We also show how variation in vascular and branching geometry persists despite observing a convergent relationship across organisms for how metabolic rate depends on body mass.
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Affiliation(s)
- Alexander B Brummer
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | | | - Jocelyn Shen
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Elif Tekin
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA
| | - Lisa P Bentley
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Vanessa Buzzard
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, USA
| | - Andrew Gray
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA
| | - Imma Oliveras
- Environmental Change Institute, School of Geography and the Environment, University of Oxford, Oxford, UK
| | - Brian J Enquist
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA.,Santa Fe Institute, Santa Fe, NM, USA
| | - Van M Savage
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, CA, USA.,Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA.,Department of Computational Medicine, David Geffen School of Medicine, University of California, Los Angeles, CA, USA.,Santa Fe Institute, Santa Fe, NM, USA
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6
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Gosselin FP. Mechanics of a plant in fluid flow. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:3533-3548. [PMID: 31198946 DOI: 10.1093/jxb/erz288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 06/06/2019] [Indexed: 06/09/2023]
Abstract
Plants live in constantly moving fluid, whether air or water. In response to the loads associated with fluid motion, plants bend and twist, often with great amplitude. These large deformations are not found in traditional engineering application and thus necessitate new specialized scientific developments. Studying fluid-structure interaction (FSI) in botany, forestry, and agricultural science is crucial to the optimization of biomass production for food, energy, and construction materials. FSIs are also central in the study of the ecological adaptation of plants to their environment. This review paper surveys the mechanics of FSI on individual plants. I present a short refresher on fluid mechanics then dive into the statics and dynamics of plant-fluid interactions. For every phenomenon considered, I examine the appropriate dimensionless numbers to characterize the problem, discuss the implications of these phenomena on biological processes, and propose future research avenues. I cover the concept of reconfiguration while considering poroelasticity, torsion, chirality, buoyancy, and skin friction. I also assess the dynamical phenomena of wave action, flutter, and vortex-induced vibrations.
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Affiliation(s)
- Frédérick P Gosselin
- Laboratory for Multiscale Mechanics, Department of Mechanical Engineering, Polytechnique Montréal, Montréal, QC, Canada
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
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7
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Albrecht A, Badel E, Bonnesoeur V, Brunet Y, Constant T, Défossez P, de Langre E, Dupont S, Fournier M, Gardiner B, Mitchell SJ, Moore JR, Moulia B, Nicoll BC, Niklas KJ, Schelhaas MJ, Spatz HC, Telewski FW. Comment on "Critical wind speed at which trees break". Phys Rev E 2016; 94:067001. [PMID: 28085329 DOI: 10.1103/physreve.94.067001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Indexed: 11/07/2022]
Abstract
Virot et al. [E. Virot et al., Phys. Rev. E 93, 023001 (2016)10.1103/PhysRevE.93.023001] assert that the critical wind speed at which ⩾50% of all trees in a population break is ≈42 m/s, regardless of tree characteristics. We show that empirical data do not support this assertion, and that the assumptions underlying the theory used by Virot et al. are inconsistent with the biomechanics of trees.
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Affiliation(s)
- Axel Albrecht
- Forest Research Institute Baden-Wuerttemberg, Wonnhaldestrasse 4, 79100 Freiburg, Germany
| | - Eric Badel
- PIAF, INRA, Université Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Vivien Bonnesoeur
- PIAF, INRA, Université Clermont Auvergne, 63000 Clermont-Ferrand, France.,LERFoB, INRA, AgroParisTech, F-54000 Nancy, France
| | - Yves Brunet
- ISPA, INRA, Bordeaux Sciences Agro, F-33140 Villenave D'Ornon, France
| | | | - Pauline Défossez
- ISPA, INRA, Bordeaux Sciences Agro, F-33140 Villenave D'Ornon, France
| | | | - Sylvain Dupont
- ISPA, INRA, Bordeaux Sciences Agro, F-33140 Villenave D'Ornon, France
| | | | - Barry Gardiner
- ISPA, INRA, Bordeaux Sciences Agro, F-33140 Villenave D'Ornon, France.,Forest Research, Northern Research Station, Roslin, EH25 9SY, Scotland, United Kingdom
| | - Stephen J Mitchell
- The University of British Columbia, 3041-2424 Main Mall, Vancouver, British Columbia, Canada V6T 1Z4
| | - John R Moore
- Scion, Private Bag 3020, Rotorua 3046, New Zealand
| | - Bruno Moulia
- PIAF, INRA, Université Clermont Auvergne, 63000 Clermont-Ferrand, France
| | - Bruce C Nicoll
- Forest Research, Northern Research Station, Roslin, EH25 9SY, Scotland, United Kingdom
| | - Karl J Niklas
- Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA
| | | | | | - Frank W Telewski
- W. J. Beal Botanical Garden, Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824, USA
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8
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Brulé V, Rafsanjani A, Pasini D, Western TL. Hierarchies of plant stiffness. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 250:79-96. [PMID: 27457986 DOI: 10.1016/j.plantsci.2016.06.002] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 05/26/2016] [Accepted: 06/01/2016] [Indexed: 05/24/2023]
Abstract
Plants must meet mechanical as well as physiological and reproductive requirements for survival. Management of internal and external stresses is achieved through their unique hierarchical architecture. Stiffness is determined by a combination of morphological (geometrical) and compositional variables that vary across multiple length scales ranging from the whole plant to organ, tissue, cell and cell wall levels. These parameters include, among others, organ diameter, tissue organization, cell size, density and turgor pressure, and the thickness and composition of cell walls. These structural parameters and their consequences on plant stiffness are reviewed in the context of work on stems of the genetic reference plant Arabidopsis thaliana (Arabidopsis), and the suitability of Arabidopsis as a model system for consistent investigation of factors controlling plant stiffness is put forward. Moving beyond Arabidopsis, the presence of morphological parameters causing stiffness gradients across length-scales leads to beneficial emergent properties such as increased load-bearing capacity and reversible actuation. Tailoring of plant stiffness for old and new purposes in agriculture and forestry can be achieved through bioengineering based on the knowledge of the morphological and compositional parameters of plant stiffness in combination with gene identification through the use of genetics.
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Affiliation(s)
- Veronique Brulé
- Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada.
| | - Ahmad Rafsanjani
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada.
| | - Damiano Pasini
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, QC, H3A OC3, Canada.
| | - Tamara L Western
- Department of Biology, McGill University, 1205 Docteur Penfield Ave., Montreal, QC, H3A 1B1, Canada.
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9
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Gardiner B, Berry P, Moulia B. Review: Wind impacts on plant growth, mechanics and damage. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 245:94-118. [PMID: 26940495 DOI: 10.1016/j.plantsci.2016.01.006] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 01/22/2016] [Accepted: 01/23/2016] [Indexed: 05/08/2023]
Abstract
Land plants have adapted to survive under a range of wind climates and this involve changes in chemical composition, physical structure and morphology at all scales from the cell to the whole plant. Under strong winds plants can re-orientate themselves, reconfigure their canopies, or shed needles, leaves and branches in order to reduce the drag. If the wind is too strong the plants oscillate until the roots or stem fail. The mechanisms of root and stem failure are very similar in different plants although the exact details of the failure may be different. Cereals and other herbaceous crops can often recover after wind damage and even woody plants can partially recovery if there is sufficient access to water and nutrients. Wind damage can have major economic impacts on crops, forests and urban trees. This can be reduced by management that is sensitive to the local site and climatic conditions and accounts for the ability of plants to acclimate to their local wind climate. Wind is also a major disturbance in many plant ecosystems and can play a crucial role in plant regeneration and the change of successional stage.
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Affiliation(s)
- Barry Gardiner
- INRA, UMR 1391 ISPA, F-33140 Villenave D'Ornon, France; Bordeaux Sciences Agro, UMR 1391 ISPA, F-33170, Gradignan, France; Forest Research, Northern Research Station, Roslin, EH25 9SY, Scotland, UK.
| | - Peter Berry
- ADAS High Mowthorpe, Duggleby, Malton, North Yorkshire YO17 8BP, UK
| | - Bruno Moulia
- INRA, UMR 547 PIAF, F-63100 Clermont-Ferrand, France; Clermont Université, Université Blaise Pascal, UMR 547 PIAF, F-63100 Clermont-Ferrand, France
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10
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Virot E, Ponomarenko A, Dehandschoewercker É, Quéré D, Clanet C. Critical wind speed at which trees break. Phys Rev E 2016; 93:023001. [PMID: 26986399 DOI: 10.1103/physreve.93.023001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Indexed: 11/07/2022]
Abstract
Data from storms suggest that the critical wind speed at which trees break is constant (≃42m/s), regardless of tree characteristics. We question the physical origin of this observation both experimentally and theoretically. By combining Hooke's law, Griffith's criterion, and tree allometry, we show that the critical wind speed indeed hardly depends on the height, diameter, and elastic properties of trees.
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Affiliation(s)
- E Virot
- LadHyX, CNRS UMR 7646, École Polytechnique, 91128 Palaiseau, France
| | - A Ponomarenko
- LadHyX, CNRS UMR 7646, École Polytechnique, 91128 Palaiseau, France.,PMMH, CNRS UMR 7636, ESPCI, 10 rue Vauquelin, 75005 Paris, France
| | - É Dehandschoewercker
- LadHyX, CNRS UMR 7646, École Polytechnique, 91128 Palaiseau, France.,PMMH, CNRS UMR 7636, ESPCI, 10 rue Vauquelin, 75005 Paris, France
| | - D Quéré
- LadHyX, CNRS UMR 7646, École Polytechnique, 91128 Palaiseau, France.,PMMH, CNRS UMR 7636, ESPCI, 10 rue Vauquelin, 75005 Paris, France
| | - C Clanet
- LadHyX, CNRS UMR 7646, École Polytechnique, 91128 Palaiseau, France.,PMMH, CNRS UMR 7636, ESPCI, 10 rue Vauquelin, 75005 Paris, France
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11
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Wind and gravity mechanical effects on leaf inclination angles. J Theor Biol 2014; 341:9-16. [DOI: 10.1016/j.jtbi.2013.09.025] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/25/2013] [Accepted: 09/18/2013] [Indexed: 11/20/2022]
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12
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Moulia B. Plant biomechanics and mechanobiology are convergent paths to flourishing interdisciplinary research. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4617-33. [PMID: 24193603 DOI: 10.1093/jxb/ert320] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- Bruno Moulia
- INRA (Institut National de la Recherche Agronomique), UMR0547 PIAF (Unité Mixte de Recherche PIAF Physique et Physiologie Intégratives de l'Arbre Fruitier et Forestier), F-63100 Clermont-Ferrand, France
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13
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Fournier M, Dlouhá J, Jaouen G, Almeras T. Integrative biomechanics for tree ecology: beyond wood density and strength. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4793-815. [PMID: 24014867 DOI: 10.1093/jxb/ert279] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Functional ecology has long considered the support function as important, but its biomechanical complexity is only just being elucidated. We show here that it can be described on the basis of four biomechanical traits, two safety traits against winds and self-buckling, and two motricity traits involved in sustaining an upright position, tropic motion velocity (MV) and posture control (PC). All these traits are integrated at the tree scale, combining tree size and shape together with wood properties. The assumption of trait constancy has been used to derive allometric scaling laws, but it was more recently found that observing their variations among environments and functional groups, or during ontogeny, provides more insights into adaptive syndromes of tree shape and wood properties. However, oversimplified expressions have often been used, possibly concealing key adaptive drivers. An extreme case of oversimplification is the use of wood basic density as a proxy for safety. Actually, as wood density is involved in stiffness, loads, and construction costs, the impact of its variations on safety is non-trivial. Moreover, other wood features, especially the microfibril angle (MFA), are also involved. Furthermore, wood is not only stiff and strong, but it also acts as a motor for MV and PC. The relevant wood trait for this is maturation strain asymmetry. Maturation strains vary with cell-wall characteristics such as MFA, rather than with wood density. Finally, the need for further studies about the ecological relevance of branching patterns, motricity traits, and growth responses to mechanical loads is discussed.
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Affiliation(s)
- M Fournier
- AgroParisTech, UMR 1092 LERFOB, 54000 Nancy, France
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14
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de Langre E. Methodological advances in predicting flow-induced dynamics of plants using mechanical-engineering theory. ACTA ACUST UNITED AC 2012; 215:914-21. [PMID: 22357585 DOI: 10.1242/jeb.058933] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The modeling of fluid-structure interactions, such as flow-induced vibrations, is a well-developed field of mechanical engineering. Many methods exist, and it seems natural to apply them to model the behavior of plants, and potentially other cantilever-like biological structures, under flow. Overcoming this disciplinary divide, and the application of such models to biological systems, will significantly advance our understanding of ecological patterns and processes and improve our predictive capabilities. Nonetheless, several methodological issues must first be addressed, which I describe here using two practical examples that have strong similarities: one from agricultural sciences and the other from nuclear engineering. Very similar issues arise in both: individual and collective behavior, small and large space and time scales, porous modeling, standard and extreme events, trade-off between the surface of exchange and individual or collective risk of damage, variability, hostile environments and, in some aspects, evolution. The conclusion is that, although similar issues do exist, which need to be exploited in some detail, there is a significant gap that requires new developments. It is obvious that living plants grow in and adapt to their environment, which certainly makes plant biomechanics fundamentally distinct from classical mechanical engineering. Moreover, the selection processes in biology and in human engineering are truly different, making the issue of safety different as well. A thorough understanding of these similarities and differences is needed to work efficiently in the application of a mechanistic approach to ecology.
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Affiliation(s)
- Emmanuel de Langre
- Department of Mechanics, LadHyX, Ecole Polytechnique, Palaiseau, France.
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15
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Eloy C. Leonardo's rule, self-similarity, and wind-induced stresses in trees. PHYSICAL REVIEW LETTERS 2011; 107:258101. [PMID: 22243116 DOI: 10.1103/physrevlett.107.258101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Indexed: 05/02/2023]
Abstract
Examining botanical trees, Leonardo da Vinci noted that the total cross section of branches is conserved across branching nodes. In this Letter, it is proposed that this rule is a consequence of the tree skeleton having a self-similar structure and the branch diameters being adjusted to resist wind-induced loads.
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Affiliation(s)
- Christophe Eloy
- Department of Mechanical and Aerospace Engineering, University of California San Diego, 9500 Gilman Drive, La Jolla California 92093-0411, USA
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