Which root architectural elements contribute the best to anchorage of Pinus species? Insights from in silico experiments
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Background and Aims
Root anchorage function is crucial for tree survival as most trees are exposed to recurrent wind throughout their lifespan. Trees exhibit a large variability of root system architecture (RSA) due genetic and environmental factors. This study aims to understand the links between RSA and tree stability.
A 3D biomechanical model was used to simulate tree overturning. To capture the variability of sinker RSA, fourteen virtual root patterns were created from an ensemble average of measured Pinus pinaster root systems. Root virtual patterns and tree-pulling simulations were verified against experimental data.
The model predicts realistic tree anchorage strength, root stress, and failure patterns. Only a few root components contribute significantly to anchorage strength. The taproot contributes the most to anchorage rigidity, representing 61 % of the anchorage strength. The windward roots failure drives ultimate anchorage failure, representing 25 % of the anchorage strength. Simulations show that root secondary thickening induces higher anchorage rigidity and increases anchorage strength by 58 %.
This innovative approach appears promising for describing tree stability and its acclimation to external constraints.
KeywordsRoot system architecture Numerical modelling Root anchorage Root stress Failure patterns
This work was financially supported by the Aquitaine Region with the FAST-A project, and by the French National Research Agency (ANR) with the TWIST (ANR-13-JS06-0006) and FOR-WIND (ANR-12-AGRO-0007) projects. This study has been also carried out in the framework of the Cluster of Excellence COTE (ANR-10-LABX-45).
We thank Dr. Alexis Achim and Dr. Barry Gardiner for fruitful discussions on plastic adaptation of roots and Dr. Mark Irvine for his technical supports for the ABAQUS computations. AMAP (Botany and Computational Plant Architecture) is a joint research unit which associates CIRAD (UMR51), CNRS (UMR5120), INRA (UMR931), IRD (2 M123), and Montpellier 2 University (UM27); http://amap.cirad.fr/. Finally, we thank two anonymous reviewers for their helpful comments.
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