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Author Lehnebach, R.; Morel, H.; Bossu, J.; Le Moguédec, G.; Amusant, N.; Beauchene, J.; Nicolini, E. url  doi
openurl 
  Title Heartwood/sapwood profile and the tradeoff between trunk and crown increment in a natural forest: the case study of a tropical tree (Dicorynia guianensis Amsh., Fabaceae) Type Journal Article
  Year 2017 Publication (down) Trees – Structure and Function Abbreviated Journal Trees – Structure and Function  
  Volume 31 Issue 1 Pages 199-214  
  Keywords Dicorynia guianensis; Growth allocation; Heartwood; Ontogeny; Sapwood; Tropical tree  
  Abstract Key message: Sapwood area and the radial growth rate of the trunk follow the same pattern at breast height, with an initial increase and subsequent constant value, resulting from the increasing growth allocation toward the crown rather than tree decline. Heartwood area and heartwood volume in the trunk increase more rapidly after this shift occurs. Abstract: Sapwood (SW) and heartwood (HW) are two functionally distinct classifications of wood in perennial stems for which quantities can vary greatly in tropical trees. Numerous positive correlations have been found between the radial growth rate (RGR) and SW quantity; however, variations in the SW/HW quantities have not been studied in light of the ontogenetic variation of RGR. Wood core sampling, intensive measurements of tree structure (number of branches, stem volumes), and radial growth monitoring were performed on an abundant and highly exploited tree species in French Guiana (Dicorynia guianensis) to investigate the relationship between RGR, SW/HW quantity, tree structure, and their variations on the course of a tree’s ontogeny. SW area and RGR followed the same pattern of variation throughout tree development, both increasing first and reaching a steady state after 50 cm DBH (diameter at breast height). After this value, we observed a strong increase in both the HW area and HW volume increment, concomitant with a more rapid increase in crown volume. The stabilization of RGR for trees with DBH > 50 cm was related not to a tree’s decline but rather to an increasing wood allocation to the crown, confirming that RGR at breast height is a poor indicator of whole-tree growth for bigger individuals. We also confirmed that HW formation is an ontogenetic process managing SW quantity that is continuously and increasingly produced within the crown as the tree grows. This study highlights the effect of growth-mediated ontogenetic changes on the localization of water and carbohydrate storage within a tree, resulting from SW and HW dynamics throughout tree ontogeny. © 2016, Springer-Verlag Berlin Heidelberg.  
  Address CIRAD, UMR EcoFoG, BP701, Kourou Cedex, French Guiana  
  Corporate Author Thesis  
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  Notes Export Date: 19 February 2017 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 733  
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Author Alméras, T.; Ghislain, B.; Clair, B.; Secerovic, A.; Pilate, G.; Fournier, M. url  doi
openurl 
  Title Quantifying the motor power of trees Type Journal Article
  Year 2018 Publication (down) Trees Abbreviated Journal  
  Volume 32 Issue 3 Pages 689-702  
  Keywords  
  Abstract Wood maturation strains can be estimated from the change in curvature that occurs when a stem grown staked in tilted position is released from the stake.
Trees have a motor system to enable upright growth in the field of gravity. This motor function is taken on by reaction wood, a special kind of wood that typically develops in leaning axes and generates mechanical force during its formation, curving up the stem and counteracting the effect of gravity or other mechanical disturbances. Quantifying the mechanical stress induced in wood during maturation is essential to many areas of research ranging from tree architecture to functional genomics. Here, we present a new method for quantifying wood maturation stress. It consists of tilting a tree, tying it to a stake, letting it grow in tilted position, and recording the change in stem curvature that occurs when the stem is released from the stake. A mechanical model is developed to make explicit the link between the change in curvature, maturation strain and morphological traits of the stem section. A parametric study is conducted to analyse how different parameters influence the change in curvature. This method is applied to the estimation of maturation strain in two different datasets. Results show that the method is able to detect genotypic variations in motor power expression. As predicted by the model, we observe that the change in stem curvature is correlated to stem diameter and diameter growth. In contrast, wood maturation strain is independent from these dimensional effects, and is suitable as an intrinsic parameter characterising the magnitude of the plant’s gravitropic reaction.
 
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1432-2285 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Alméras2018 Serial 835  
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Author Bossu, J.; Lehnebach, R.; Corn, S.; Regazzi, A.; Beauchene, J.; Clair, B. url  doi
openurl 
  Title Interlocked grain and density patterns in Bagassa guianensis: changes with ontogeny and mechanical consequences for trees Type Journal Article
  Year 2018 Publication (down) Trees Abbreviated Journal  
  Volume 32 Issue 6 Pages 1643-1655  
  Keywords  
  Abstract Interlocked grain and basic density increase from pith to bark in Bagassa guianensis and greatly improve trunk torsional stiffness and wood tenacity in the radial plane.  
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  ISSN 1432-2285 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Bossu2018 Serial 852  
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Author Gonzalès-Melo, Andrès ; Posada, Juan Manuel ; Beauchêne, Jacques ; Lehnebach, Romain ; Leviennois, Sébastien ; Rivera, Katherine ; Clair, Bruno doi  openurl
  Title Radial variations in wood functional traits in a rain forest from eastern Amazonia Type Journal Article
  Year 2021 Publication (down) Trees Abbreviated Journal  
  Volume 36 Issue Pages 569–581  
  Keywords  
  Abstract Trees can modify their wood structure in response to changes in mechanical, hydraulic and storage demands during their life-cycles. Thus, examining radial variations in wood traits is important to expand our knowledge of tree functioning and species ecological strategies. Yet, several aspects of radial changes in wood functional traits are still poorly understood, especially in angiosperm trees from tropical humid forests. Here, we examined radial shifts in wood traits in trunks of tropical forest species and explored their potential ecological implications. We first examined radial variations in wood specific gravity (WSG). Then, we asked what anatomical traits drove radial variations in WSG, and whether WSG, vessel fraction and specific hydraulic conductivity vary independently from each other along the radius gradients. We measured WSG and eight wood anatomical traits, at different radial positions along the trunks, in 19 tree species with contrasting shade-tolerance from a lowland tropical forest in eastern Amazonia. Most species had significant radials shifts in WSG. Positive radial gradients in WSG (i.e., increments from pith to bark) were common among shade-intolerant species and were explained by different combinations of fiber and parenchyma traits, while negative radial shifts in WSG (e.g., decreases towards the bark) were present in shade-tolerants, but were generally weakly related to anatomical traits. We also found that, in general, WSG was unrelated to vessel fraction and specific hydraulic conductivity in any radial position. This study illustrates the contrasting radial variations in wood functional traits that occur in tree species from a humid lowland tropical forest. In particular, our results provide valuable insights into the anatomical traits driving WSG variations during tree development. These insights are important to expand our knowledge on tree ecological strategies by providing evidence on how wood allocation varies as trees grow, which in turn can be useful in studying trait-demography associations, and in estimating tree above-ground biomass.  
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  Publisher Springer Link Place of Publication Editor  
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  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 1037  
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Author Almeras, T. openurl 
  Title Mechanical analysis of the strains generated by water tension in plant stems. Part II: strains in wood and bark and apparent compliance Type Journal Article
  Year 2008 Publication (down) Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 28 Issue 10 Pages 1513-1523  
  Keywords biomechanics; calibration; diurnal strains; mechanical model; multilayer cylinder; water potential  
  Abstract Tree steins shrink in diameter during the day and swell during the night in response to changes in water tension in the xylem. Stein shrinkage can easily be measured in a nondestructive way, to derive continuous information about tree water status. The relationship between the strain and the change in water tension can be evaluated by empirical calibrations, or can be related to the structure of the plant. A mechanical analysis was performed to make this relationship explicit. The stem is modeled as a cylinder made of multiple layers of tissues, including heartwood, sapwood, and inner and outer bark. The effect of changes in water tension on the apparent strain at the surface of a tissue is quantified as a function of parameters defining stem anatomy and the mechanical properties of the tissues. Various possible applications in the context of tree physiology are suggested.  
  Address INRA UMR Ecofog, Kourou 97379, French Guiana, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000260027200009 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 129  
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Author Almeras, T.; Gril, J. openurl 
  Title Mechanical analysis of the strains generated by water tension in plant stems. Part 1: stress transmission from the water to the cell walls Type Journal Article
  Year 2007 Publication (down) Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 27 Issue 11 Pages 1505-1516  
  Keywords biomechanics; cell mechanics; diurnal strains; mechanical model; multilayer cylinder; stress transtnissionjactor  
  Abstract Plant tissues shrink and swell in response to changes in water pressure. These strains can be easily measured, e.g., at the surface of tree stems, to obtain indirect information about plant water status and other physiological parameters. We developed a mechanical model to clarify how water pressure is transmitted to cell walls and causes shrinkage of plant tissues, particularly in the case of thick-walled cells such as wood fibers. Our analysis shows that the stress inside the fiber cell walls is lower than the water tension. The difference is accounted for by a stress transmission factor that depends on two main effects. The first effect is the dilution of the stress through the cell wall, because water acts at the lumen border and is transmitted to the cuter border of the cell, which has a larger circumference. The second effect is the partial conversion of radial stress into tangential stress. Both effects are quantified as functions of parameters of the cell wall structure and its mechanical properties.  
  Address INRA, UMR Ecofog, F-97379 Kourou, French Guiana, France, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000250847000001 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 152  
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Author Coste, S.; Roggy, J.C.; Imbert, P.; Born, C.; Bonal, D.; Dreyer, E. openurl 
  Title Leaf photosynthetic traits of 14 tropical rain forest species in relation to leaf nitrogen concentration and shade tolerance Type Journal Article
  Year 2005 Publication (down) Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 25 Issue 9 Pages 1127-1137  
  Keywords functional diversity; leaf carbon; leaf nitrogen; nitrogen-use efficiency; photosynthetic capacity; tropical rain forest  
  Abstract Variability of leaf traits related to photosynthesis was assessed in seedlings from 14 tree species growing in the tropical rain forest of French Guiana. Leaf photosynthetic capacity (maximum rate of carboxylation and maximum rate of electron transport) was estimated by fitting a biochemical model of photosynthesis to response curves of net CO2 assimilation rate versus intercellular CO2 mole fraction. Leaf morphology described by leaf mass per unit leaf area (LMA), density and thickness, as well as area- and mass-based nitrogen (N) and carbon (C) concentrations, were recorded on the same leaves. Large interspecific variability was detected in photosynthetic capacity as well as in leaf structure and leaf N and C concentrations. No correlation was found between leaf thickness and density. The correlations between area- and mass-based leaf N concentration and photosynthetic capacity were poor. Conversely, the species differed greatly in relative N allocation to carboxylation and bioenergetics. Principal component analysis (PCA) revealed that, of the recorded traits, only the computed fraction of total leaf N invested in photosynthesis was tightly correlated to photosynthetic capacity. We also used PCA to test to what extent species with similar shade tolerances displayed converging leaf traits related to photosynthesis. No clear-cut ranking could be detected among the shade-tolerant groups, as confirmed by a one-way ANOVA. We conclude that the large interspecific diversity in photosynthetic capacity was mostly explained by differences in the relative allocation of N to photosynthesis and not by leaf N concentration, and that leaf traits related to photosynthetic capacity did not discriminate shade-tolerance ranking of these tropical tree species.  
  Address CNRS Ecol Forets Guyane, INRA, ENGREF,CIRAD, Unite Mixte Rech, Kourou 97387, French Guiana, Email: roggy.j@cirad.fr  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000231555200005 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 230  
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Author Bosc, A.; De Grandcourt, A.; Loustau, D. openurl 
  Title Variability of stem and branch maintenance respiration in a Pinus pinaster tree Type Journal Article
  Year 2003 Publication (down) Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 23 Issue 4 Pages 227-236  
  Keywords model; nitrogen; phloem; sapwood; temperature  
  Abstract The relationship between maintenance respiration (R.) of woody organs and their structural characteristics was explored in adult Pinus pinaster Ait. trees. We measured R-m on 75 stem and branch segments of different ages (from 3 to 24 years) and diameters (from 1 to 35 cm). The temperature response of R-m was derived from field measurements based on a classical exponential function with Q(10) = 2.13. Relationships between R-m and the dimensions of the woody organs were analyzed under controlled conditions in the laboratory. The surface area of a woody organ was a better predictor of R-m than volume, but surface area failed to account for the observed within-tree variability of R-m among stems, branches and twigs. Two simple models were proposed to predict the variability of R-m at 15 degreesC in an adult tree. Model 1, a linear function model based on the dry mass and nitrogen concentration of sapwood and phloem tissues, explained most of the variability of R-m in branches and stems (R-2 = 0.97). We concluded that the respective contributions of the phloem and sapwood depend on the location and diameter of the woody organ. Model 2, a power-law function model based on the length, diameter and age of the sample, explained the same variance of R-m as Model 1 and is appropriate for scaling R-m to the stand level. Models 1 and 2 appear to explain a larger variability of R-m than models based on stem area or sapwood mass.  
  Address INRA, F-33612 Cestas, France, Email: alexandre.bosc@pierroton.inra.fr  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000181841200002 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 246  
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Author Cochard, H.; Coste, S.; Chanson, B.; Guehl, J.M.; Nicolini, E. openurl 
  Title Hydraulic architecture correlates with bud organogenesis and primary shoot growth in beech (Fagus sylvatica) Type Journal Article
  Year 2005 Publication (down) Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 25 Issue 12 Pages 1545-1552  
  Keywords development; hydraulic conductance; leaf primordia; meristem; xylem  
  Abstract In beech (Fagus sylvatica L.), the number of leaf primordia preformed in the buds determines the length and the type (long versus short) of annual growth units, and thus, branch growth and architecture. We analyzed the correlation between the number of leaf primordia and the hydraulic conductance of the vascular system connected to the buds. Terminal buds of short growth units and axillary buds of long growth units on lower branches of mature trees were examined. Buds with less than four and more than five leaf primordia formed short and long growth units, respectively. Irrespective of the type of growth unit the bud was formed on, the occurrence of a large number of leaf primordia was associated with high xylem hydraulic conductance. Xylem conductance was correlated to the area of the outermost annual ring. These results suggest that organogenesis and primary growth in buds correlates with secondary growth of the growth units and thus with their hydraulic architecture. Possible causal relationships between the variables are discussed.  
  Address INRA UBP, UMR PIAF, F-63039 Clermont Ferrand, France, Email: cochard@clermont.inra.fr  
  Corporate Author Thesis  
  Publisher HERON PUBLISHING Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0829-318X ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000234019900008 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 281  
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Author Roussel, J.-R.; Clair, B. url  openurl
  Title Evidence of the late lignification of the G-layer in Simarouba tension wood, to assist understanding how non-G-layer species produce tensile stress Type Journal Article
  Year 2015 Publication (down) Tree Physiology Abbreviated Journal Tree Physiology  
  Volume 35 Issue 12 Pages 1366-1377  
  Keywords maturation stress generation; ontogeny; Simarouba amara Aubl.; tension wood cell wall; tree biomechanics  
  Abstract To recover verticality after disturbance, angiosperm trees produce 'tension wood' allowing them to bend actively. The driving force of the tension has been shown to take place in the G-layer, a specific unlignified layer of the cell wall observed in most temperate species. However, in tropical rain forests, the G-layer is often absent and the mechanism generating the forces to reorient trees remains unclear. A study was carried out on tilted seedlings, saplings and adult Simarouba amara Aubl. trees – a species known to not produce a G-layer. Microscopic observations were done on sections of normal and tension wood after staining or observed under UV light to assess the presence/absence of lignin. We showed that S. amara produces a cell-wall layer with all of the characteristics typical of G-layers, but that this G-layer can be observed only as a temporary stage of the cell-wall development because it is masked by a late lignification. Being thin and lignified, tension wood fibres cannot be distinguished from normal wood fibres in the mature wood of adult trees. These observations indicate that the mechanism generating the high tensile stress in tension wood is likely to be the same as that in species with a typical G-layer and also in species where the G-layer cannot be observed in mature cells. © 2015 The Author 2015. Published by Oxford University Press. All rights reserved.  
  Address CNRS, UMR Ecologie des Forêts de Guyane (EcoFoG), Campus Agronomique, BP 701, Kourou, France  
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  Notes Export Date: 25 March 2016 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 672  
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