T. Fourcaud - Academia.edu (original) (raw)
Papers by T. Fourcaud
Arboriculture & Urban Forestry
To evaluate the efficiency of ground-penetrating radar (GPR) to map root systems of urban trees i... more To evaluate the efficiency of ground-penetrating radar (GPR) to map root systems of urban trees in situ, this technique was tested on three trees in an urban environment. After carrying out the extremely rapid GPR tests around the bases of the sample trees, root systems were excavated with an air spade, which produces a supersonic jet of air used to remove soil from roots. Photographs were taken of root system transects for comparison with GPR images. Root system architecture was then quantified for one pine tree, and a two-dimensional image of the root system was reconstructed using AMAPmod software. A comparison of actual roots with images hand drawn from the GPR data showed that the technique is reliable for mapping large roots in the horizontal plane only. Most errors in data from the GPR method were induced when the root systems were manually redrawn, and from roots running parallel to the electromagnetic signal in the vertical plane. These roots could not be identified by GPR....
The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, 2000
Page 206. A. Stokes (ed.), The Supporting Roots of Trees and Woody Plants: Form, Function and Phy... more Page 206. A. Stokes (ed.), The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, 195-207. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 195 A model simulating interactions between ...
2012 IEEE 4th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications, 2012
ABSTRACT This paper presents a spatio-temporal model coupling tree growth and tree biomechanics. ... more ABSTRACT This paper presents a spatio-temporal model coupling tree growth and tree biomechanics. This model takes the form of partial differential equations. Different numerical methods have been implemented and compared in order to integrate the model equations at the branch scale. The model takes into account the three main components involved in the tropism of lignified axes, namely the primary reorientation of the branch tip, the stiffness increase due to secondary growth and the secondary reorientation involved by a differential in cell maturation strains. Simulation results are shown to demonstrate the capacities of the model to simulate realistic stem/branch motions.
ABSTRACT PMA06: The Second International Symposium on Plant Growth Modeling, Simulation, Visualiz... more ABSTRACT PMA06: The Second International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications, 13-17 novembre 2006, Beijing, P. R. China.
ABSTRACT Mention d'édition : CRC PRESS BOOK
Plant and Soil, 2011
... Implementation of the model Operator splitting method ... The numerical schemes (upwind first... more ... Implementation of the model Operator splitting method ... The numerical schemes (upwind first order, TR-BDF2 and exact schemes) and their numerical stability properties are de-tailed below and in the appendix (see Appendix). ...
New Phytologist, 2005
This study aims to link three-dimensional coarse root architecture to tree stability in mature ti... more This study aims to link three-dimensional coarse root architecture to tree stability in mature timber trees with an average of 1-m rooting depth. Undamaged and uprooted trees were sampled in a stand damaged by a storm. Root architecture was measured by three-dimensional (3-D) digitizing. The distribution of root volume by root type and in wind-oriented sectors was analysed. Mature Pinus pinaster root systems were organized in a rigid 'cage' composed of a taproot, the zone of rapid taper of horizontal surface roots and numerous sinkers and deep roots, imprisoning a large mass of soil and guyed by long horizontal surface roots. Key compartments for stability exhibited strong selective leeward or windward reinforcement. Uprooted trees showed a lower cage volume, a larger proportion of oblique and intermediate depth horizontal roots and less wind-oriented root reinforcement. Pinus pinaster stability on moderately deep soils is optimized through a typical rooting pattern and a considerable structural adaptation to the prevailing wind and soil profile.
Journal of Theoretical Biology, 2005
European Journal of Soil Science, 2005
ABSTRACT
Ecological Modelling, 2014
ABSTRACT Vegetation can play an important role in stabilizing soil against shallow landslides. Us... more ABSTRACT Vegetation can play an important role in stabilizing soil against shallow landslides. Using a three-dimensional (3D) finite element method, we developed a model to study the impact of different management scenarios on slope stability in mountain forests. Ground truth data were obtained from a mixed forest ecosystem situated at an altitude of 1400 m a.s.l. in the French Alps. Five scenarios representing the forest at different spatial and temporal stages of management were selected: [A] bare soil, [B] tree island (i.e. tree groups growing in clusters) on bare soil, [C] new gap (i.e. canopy free zones with little understorey) in homogeneous forest, [D] old gap (i.e. canopy free zones with abundant understorey) in homogeneous forest and [E] homogeneous forest. For scenarios [B], [C] and [D], the locations of the vegetated patch along the slope (top, centre and toe) were also tested, to determine if vegetation patterns influenced slope stability. As plant roots play a crucial role in reinforcing soil, we altered the 3D spatial distribution of root density in the model using real data. By calculating the factor of safety (FoS), i.e. a measure of the likelihood that the slope will fail, we show that slope morphology, including angle and soil depth, play an essential role in slope stability. Vegetation also exhibited a positive effect on slope stability, but the efficiency of this effect was significantly influenced by slope morphology and root distribution with regard to soil depth. In particular, if a layer of soil beneath the most superficial rooting zone contained few roots, slope integrity was compromised. Compared to bare soil, the FoS increase due to vegetation was only ≤0.2 (i.e. ≤15%), when deeper soil layers contained few or no roots. However, if the soil profile contained roots throughout, the FoS increase was >25% higher. We highlight the importance of taking into account spatial complexity and refining the output, i.e. FoS, during the modelling of slope stability, which can only be achieved through the use of 3D models.
Ecological Engineering, 2013
Ecological Engineering, 2010
The influence of plant diversity on slope stability was investigated at early phases of successio... more The influence of plant diversity on slope stability was investigated at early phases of succession in a mixed forest in Sichuan, China. The first phase comprised big node bamboo (Phyllostachys nidularia Munro) only. In the second phase, bamboo co-existed with deciduous tree species and in the third phase, deciduous species existed alone. Root density at different depths and root tensile
La plupart des modeles de croissance des arbres sont bases sur le processus d'allocation de c... more La plupart des modeles de croissance des arbres sont bases sur le processus d'allocation de carbone. Le fonctionnement physiologique de la plante est pris en compte dans la modelisation. La production vegetative est correlee au potentiel d'assimilation pendant la photosynthese. Le plus important modele decoule de la theorie des tuyaux de Shinozaki basee sur la lumiere interceptee. Un modele recent integre la geometrie des organes vegetatifs avec leur capacite d'assimilation. Le programme GROGRA, base sur le concept informatique des L-Systemes, etablit des interactions entre l'architecture de la plante, la competition et l'allocation du carbone. Ce document decrit brievement une nouvelle approche de la modelisation de la croissance des arbres developpee par le programme AMAPpara. Elle vise a integrer les connaissances sur l'architecture des plantes et les processus physiologiques du transport de l'eau et de l'allocation du carbone dans la plante. Le modele de fonctionnement est fonde sur une hypothetique relation entre la production de metabolites et la transpiration. La sensibilite de la croissance de la plante a la modification de la disposition et de la ramification des branches peut etre evaluee a partir des resultats de la simulation
Arboriculture & Urban Forestry
To evaluate the efficiency of ground-penetrating radar (GPR) to map root systems of urban trees i... more To evaluate the efficiency of ground-penetrating radar (GPR) to map root systems of urban trees in situ, this technique was tested on three trees in an urban environment. After carrying out the extremely rapid GPR tests around the bases of the sample trees, root systems were excavated with an air spade, which produces a supersonic jet of air used to remove soil from roots. Photographs were taken of root system transects for comparison with GPR images. Root system architecture was then quantified for one pine tree, and a two-dimensional image of the root system was reconstructed using AMAPmod software. A comparison of actual roots with images hand drawn from the GPR data showed that the technique is reliable for mapping large roots in the horizontal plane only. Most errors in data from the GPR method were induced when the root systems were manually redrawn, and from roots running parallel to the electromagnetic signal in the vertical plane. These roots could not be identified by GPR....
The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, 2000
Page 206. A. Stokes (ed.), The Supporting Roots of Trees and Woody Plants: Form, Function and Phy... more Page 206. A. Stokes (ed.), The Supporting Roots of Trees and Woody Plants: Form, Function and Physiology, 195-207. © 2000 Kluwer Academic Publishers. Printed in the Netherlands. 195 A model simulating interactions between ...
2012 IEEE 4th International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications, 2012
ABSTRACT This paper presents a spatio-temporal model coupling tree growth and tree biomechanics. ... more ABSTRACT This paper presents a spatio-temporal model coupling tree growth and tree biomechanics. This model takes the form of partial differential equations. Different numerical methods have been implemented and compared in order to integrate the model equations at the branch scale. The model takes into account the three main components involved in the tropism of lignified axes, namely the primary reorientation of the branch tip, the stiffness increase due to secondary growth and the secondary reorientation involved by a differential in cell maturation strains. Simulation results are shown to demonstrate the capacities of the model to simulate realistic stem/branch motions.
ABSTRACT PMA06: The Second International Symposium on Plant Growth Modeling, Simulation, Visualiz... more ABSTRACT PMA06: The Second International Symposium on Plant Growth Modeling, Simulation, Visualization and Applications, 13-17 novembre 2006, Beijing, P. R. China.
ABSTRACT Mention d'édition : CRC PRESS BOOK
Plant and Soil, 2011
... Implementation of the model Operator splitting method ... The numerical schemes (upwind first... more ... Implementation of the model Operator splitting method ... The numerical schemes (upwind first order, TR-BDF2 and exact schemes) and their numerical stability properties are de-tailed below and in the appendix (see Appendix). ...
New Phytologist, 2005
This study aims to link three-dimensional coarse root architecture to tree stability in mature ti... more This study aims to link three-dimensional coarse root architecture to tree stability in mature timber trees with an average of 1-m rooting depth. Undamaged and uprooted trees were sampled in a stand damaged by a storm. Root architecture was measured by three-dimensional (3-D) digitizing. The distribution of root volume by root type and in wind-oriented sectors was analysed. Mature Pinus pinaster root systems were organized in a rigid 'cage' composed of a taproot, the zone of rapid taper of horizontal surface roots and numerous sinkers and deep roots, imprisoning a large mass of soil and guyed by long horizontal surface roots. Key compartments for stability exhibited strong selective leeward or windward reinforcement. Uprooted trees showed a lower cage volume, a larger proportion of oblique and intermediate depth horizontal roots and less wind-oriented root reinforcement. Pinus pinaster stability on moderately deep soils is optimized through a typical rooting pattern and a considerable structural adaptation to the prevailing wind and soil profile.
Journal of Theoretical Biology, 2005
European Journal of Soil Science, 2005
ABSTRACT
Ecological Modelling, 2014
ABSTRACT Vegetation can play an important role in stabilizing soil against shallow landslides. Us... more ABSTRACT Vegetation can play an important role in stabilizing soil against shallow landslides. Using a three-dimensional (3D) finite element method, we developed a model to study the impact of different management scenarios on slope stability in mountain forests. Ground truth data were obtained from a mixed forest ecosystem situated at an altitude of 1400 m a.s.l. in the French Alps. Five scenarios representing the forest at different spatial and temporal stages of management were selected: [A] bare soil, [B] tree island (i.e. tree groups growing in clusters) on bare soil, [C] new gap (i.e. canopy free zones with little understorey) in homogeneous forest, [D] old gap (i.e. canopy free zones with abundant understorey) in homogeneous forest and [E] homogeneous forest. For scenarios [B], [C] and [D], the locations of the vegetated patch along the slope (top, centre and toe) were also tested, to determine if vegetation patterns influenced slope stability. As plant roots play a crucial role in reinforcing soil, we altered the 3D spatial distribution of root density in the model using real data. By calculating the factor of safety (FoS), i.e. a measure of the likelihood that the slope will fail, we show that slope morphology, including angle and soil depth, play an essential role in slope stability. Vegetation also exhibited a positive effect on slope stability, but the efficiency of this effect was significantly influenced by slope morphology and root distribution with regard to soil depth. In particular, if a layer of soil beneath the most superficial rooting zone contained few roots, slope integrity was compromised. Compared to bare soil, the FoS increase due to vegetation was only ≤0.2 (i.e. ≤15%), when deeper soil layers contained few or no roots. However, if the soil profile contained roots throughout, the FoS increase was >25% higher. We highlight the importance of taking into account spatial complexity and refining the output, i.e. FoS, during the modelling of slope stability, which can only be achieved through the use of 3D models.
Ecological Engineering, 2013
Ecological Engineering, 2010
The influence of plant diversity on slope stability was investigated at early phases of successio... more The influence of plant diversity on slope stability was investigated at early phases of succession in a mixed forest in Sichuan, China. The first phase comprised big node bamboo (Phyllostachys nidularia Munro) only. In the second phase, bamboo co-existed with deciduous tree species and in the third phase, deciduous species existed alone. Root density at different depths and root tensile
La plupart des modeles de croissance des arbres sont bases sur le processus d'allocation de c... more La plupart des modeles de croissance des arbres sont bases sur le processus d'allocation de carbone. Le fonctionnement physiologique de la plante est pris en compte dans la modelisation. La production vegetative est correlee au potentiel d'assimilation pendant la photosynthese. Le plus important modele decoule de la theorie des tuyaux de Shinozaki basee sur la lumiere interceptee. Un modele recent integre la geometrie des organes vegetatifs avec leur capacite d'assimilation. Le programme GROGRA, base sur le concept informatique des L-Systemes, etablit des interactions entre l'architecture de la plante, la competition et l'allocation du carbone. Ce document decrit brievement une nouvelle approche de la modelisation de la croissance des arbres developpee par le programme AMAPpara. Elle vise a integrer les connaissances sur l'architecture des plantes et les processus physiologiques du transport de l'eau et de l'allocation du carbone dans la plante. Le modele de fonctionnement est fonde sur une hypothetique relation entre la production de metabolites et la transpiration. La sensibilite de la croissance de la plante a la modification de la disposition et de la ramification des branches peut etre evaluee a partir des resultats de la simulation