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Author Grangier, J.; Dejean, A.; Male, P.J.G.; Solano, P.J.; Orivel, J. openurl 
  Title Mechanisms driving the specificity of a myrmecophyte-ant association Type Journal Article
  Year 2009 Publication Biological Journal of the Linnean Society Abbreviated Journal Biol. J. Linnean Soc.  
  Volume 97 Issue 1 Pages 90-97  
  Keywords Allomerus decemarticulatus; exclusion filters; Hirtella physophora; horizontal transmission; host recognition; mutualism  
  Abstract In the understory of pristine Guianese forests, the myrmecophyte Hirtella physophora almost exclusively shelters colonies of the plant-ant Allomerus decemarticulatus in its leaf pouches. We experimentally tested three non-mutually exclusive hypotheses concerning phenomena that can determine the species specificity of this association throughout the foundation stage of the colonies: (1) interspecific competition results in the overwhelming presence of A. decemarticulatus queens or incipient colonies; (2) exclusion filters prevent other ant species from entering the leaf pouches; and (3) host-recognition influences the choice of founding queens, especially A. decemarticulatus. Neither interspecific competition, nor the purported exclusion filters that we examined play a major role in maintaining the specificity of this association. Unexpectedly, the plant trichomes lining the domatia appear to serve as construction material during claustral foundation rather than as a filter. Finally, A. decemarticulatus queens are able to identify their host plant from a distance through chemical and/or visual cues, which is rarely demonstrated in studies on obligatory ant-plant associations. We discuss the possibility that this specific host-recognition ability could participate in shaping a compartmentalized plant-ant community where direct competition between ant symbionts is limited. (C) 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 97, 90-97.  
  Address [Grangier, Julien; Male, Pierre-Jean G.; Orivel, Jerome] Univ Toulouse 3, Lab Evolut & Divers Biol, CNRS, UMR 5174, F-31062 Toulouse 9, France, Email: grangier@cict.fr  
  Corporate Author Thesis  
  Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0024-4066 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000265406800008 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 114  
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Author Patino, S.; Lloyd, J.; Paiva, R.; Baker, T.R.; Quesada, C.A.; Mercado, L.M.; Schmerler, J.; Schwarz, M.; Santos, A.J.B.; Aguilar, A.; Czimczik, C.I.; Gallo, J.; Horna, V.; Hoyos, E.J.; Jimenez, E.M.; Palomino, W.; Peacock, J.; Pena-Cruz, A.; Sarmiento, C.; Sota, A.; Turriago, J.D.; Villanueva, B.; Vitzthum, P.; Alvarez, E.; Arroyo, L.; Baraloto, C.; Bonal, D.; Chave, J.; Costa, A.C.L.; Herrera, R.; Higuchi, N.; Killeen, T.; Leal, E.; Luizao, F.; Meir, P.; Monteagudo, A.; Neil, D.; Nunez-Vargas, P.; Penuela, M.C.; Pitman, N.; Priante, N.; Prieto, A.; Panfil, S.N.; Rudas, A.; Salomao, R.; Silva, N.; Silveira, M.; deAlmeida, S.S.; Torres-Lezama, A.; Vasquez-Martinez, R.; Vieira, I.; Malhi, Y.; Phillips, O.L. openurl 
  Title Branch xylem density variations across the Amazon Basin Type Journal Article
  Year 2009 Publication Biogeosciences Abbreviated Journal Biogeosciences  
  Volume 6 Issue 4 Pages 545-568  
  Keywords  
  Abstract Xylem density is a physical property of wood that varies between individuals, species and environments. It reflects the physiological strategies of trees that lead to growth, survival and reproduction. Measurements of branch xylem density, rho(x), were made for 1653 trees representing 598 species, sampled from 87 sites across the Amazon basin. Measured values ranged from 218 kg m(-3) for a Cordia sagotii (Boraginaceae) from Mountagne de Tortue, French Guiana to 1130 kg m(-3) for an Aiouea sp. (Lauraceae) from Caxiuana, Central Para, Brazil. Analysis of variance showed significant differences in average rho(x) across regions and sampled plots as well as significant differences between families, genera and species. A partitioning of the total variance in the dataset showed that species identity (family, genera and species) accounted for 33% with environment (geographic location and plot) accounting for an additional 26%; the remaining “residual” variance accounted for 41% of the total variance. Variations in plot means, were, however, not only accountable by differences in species composition because xylem density of the most widely distributed species in our dataset varied systematically from plot to plot. Thus, as well as having a genetic component, branch xylem density is a plastic trait that, for any given species, varies according to where the tree is growing in a predictable manner. Within the analysed taxa, exceptions to this general rule seem to be pioneer species belonging for example to the Urticaceae whose branch xylem density is more constrained than most species sampled in this study. These patterns of variation of branch xylem density across Amazonia suggest a large functional diversity amongst Amazonian trees which is not well understood.  
  Address [Patino, S.; Aguilar, A.; Jimenez, E. M.; Vitzthum, P.; Penuela, M. C.] Univ Nacl Colombia, Inst Amazonico Invest Imani, Grp Ecol Ecosistemas Terrestres Trop, Leticia, Amazonas, Colombia, Email: sanpatiga@gmail.com  
  Corporate Author Thesis  
  Publisher COPERNICUS PUBLICATIONS Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1726-4170 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000265743200004 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 115  
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Author Paine, C.E.T.; Harms, K.E. openurl 
  Title Quantifying the effects of seed arrival and environmental conditions on tropical seedling community structure Type Journal Article
  Year 2009 Publication Oecologia Abbreviated Journal Oecologia  
  Volume 160 Issue 1 Pages 139-150  
  Keywords Community assembly; Dispersal; Niche differentiation; Seed addition; Variance partitioning  
  Abstract Though it is recognized that both stochastic and deterministic processes structure all communities, empirical assessments of their relative importance are rare, particularly within any single community. In this paper, we quantify the dynamic effects of dispersal assembly and niche assembly on the seedling layer in a diverse neotropical rain forest. The two theories make divergent predictions regarding the roles of seed arrival and environmental heterogeneity in generating community structure. Put simply, dispersal assembly posits that the stochasticity inherent to seed arrival structures communities, whereas niche assembly suggests that heterogeneity in post-dispersal environmental conditions is more important. We experimentally sowed 15,132 seeds of eight tree species at varying levels of density and diversity. Every six months we censused the seedlings that germinated and assessed the abiotic and biotic conditions of each plot. We assessed the density, diversity, and species composition of three nested subsets of the seedling layer: seedlings germinated from sown seeds, all seedlings germinated between July 2003 and 2004, and all woody seedlings. We partitioned the variance in density and diversity of each subset of the seedling layer into components representing seed-addition treatments and environmental conditions at 6- to 12-month intervals. Seed additions initially explained more variance in the density and diversity than did environmental heterogeneity for seven of eight sown species, but explained little variance in the density or diversity of the entire seedling layer. Species composition was better explained by seed-addition treatments than by environmental heterogeneity for all three subsets and in all time periods. Nevertheless, the variance in community structure explained by seed-addition treatments declined over the two years following germination, presaging shifts in the relative importance of dispersal assembly and niche assembly. Our study quantifies how dispersal assembly and niche assembly may vary among the components of an ecological community and shift dynamically through time.  
  Address [Paine, C. E. Timothy; Harms, Kyle E.] Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA, Email: timothy.paine@ecofog.gf  
  Corporate Author Thesis  
  Publisher SPRINGER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0029-8549 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000265100500014 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 116  
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Author Malhi, Y.; Aragao, L.E.O.C.; Metcalfe, D.B.; Paiva, R.; Quesada, C.A.; Almeida, S.; Anderson, L.; Brando, P.; Chambers, J.Q.; da Costa, A.C.L.; Hutyra, L.R.; Oliveira, P.; Patino, S.; Pyle, E.H.; Robertson, A.L.; Teixeira, L.M. openurl 
  Title Comprehensive assessment of carbon productivity, allocation and storage in three Amazonian forests Type Journal Article
  Year 2009 Publication Global Change Biology Abbreviated Journal Glob. Change Biol.  
  Volume 15 Issue 5 Pages 1255-1274  
  Keywords allocation; Amazonia; carbon; growth; litterfall; productivity; respiration; roots; soil; tropical forest  
  Abstract The allocation and cycling of carbon (C) within forests is an important component of the biospheric C cycle, but is particularly understudied within tropical forests. We synthesise reported and unpublished results from three lowland rainforest sites in Amazonia (in the regions of Manaus, Tapajos and Caxiuana), all major sites of the Large-Scale Biosphere-Atmosphere Programme (LBA). We attempt a comprehensive synthesis of the C stocks, nutrient status and, particularly, the allocation and internal C dynamics of all three sites. The calculated net primary productivities (NPP) are 10.1 +/- 1.4 Mg C ha(-1) yr(-1) (Manaus), 14.4 +/- 1.3 Mg C ha(-1) yr(-1) (Tapajos) and 10.0 +/- 1.2 Mg C ha(-1) yr(-1) (Caxiuana). All errors bars report standard errors. Soil and leaf nutrient analyses indicate that Tapajos has significantly more plant-available phosphorus and calcium. Autotrophic respiration at all three sites (14.9-21.4 Mg C ha yr(-1)) is more challenging to measure, with the largest component and greatest source of uncertainty being leaf dark respiration. Comparison of measured soil respiration with that predicted from C cycling measurements provides an independent constraint. It shows general good agreement at all three sites, with perhaps some evidence for measured soil respiration being less than expected. Twenty to thirty percent of fixed C is allocated belowground. Comparison of gross primary productivity (GPP), derived from ecosystem flux measurements with that derived from component studies (NPP plus autotrophic respiration) provides an additional crosscheck. The two approaches are in good agreement, giving increased confidence in both approaches to estimating GPP. The ecosystem carbon-use efficiency (CUEs), the ratio of NPP to GPP, is similar at Manaus (0.34 +/- 0.10) and Caxiuana (0.32 +/- 0.07), but may be higher at Tapajos (0.49 +/- 0.16), although the difference is not significant. Old growth or infertile tropical forests may have low CUE compared with recently disturbed and/or fertile forests.  
  Address [Malhi, Yadvinder; Aragao, Luiz Eduardo O. C.; Metcalfe, Daniel B.; Anderson, Liana] Sch Geog & Environm, Environm Change Inst, Oxford OX1 3QY, England, Email: yadvinder.malhi@ouce.ox.ac.uk  
  Corporate Author Thesis  
  Publisher WILEY-BLACKWELL PUBLISHING, INC Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1354-1013 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000265033700015 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 117  
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Author Paine, C.E.T.; Harms, K.E.; Ramos, J. openurl 
  Title Supplemental irrigation increases seedling performance and diversity in a tropical forest Type Journal Article
  Year 2009 Publication Journal of Tropical Ecology Abbreviated Journal J. Trop. Ecol.  
  Volume 25 Issue Pages 171-180  
  Keywords diversity; Estacion Biologica Los Amigos; habitat filtering; palms; Peru; precipitation; seasonality; seedling recruitment  
  Abstract Diversity is positively correlated with water availability at global, continental and regional scales. With the objective of better understanding the mechanisms that drive these relationships. we investigated the degree to which variation in water availability affects the performance (recruitment, growth a rid survival) of juvenile trees. Precipitation was supplemented throughout two dry seasons in a seasonal moist forest in south-eastern Peru. Supplementing precipitation by 160 mm mo(-1), we increased soil moisture by 17%. To generate seedling communities or known species composition, we sowed 3840 seeds of 12 species. We monitored the fates of the 554 seedlings recruited from the sown seeds. as well as 1856 older non-sown seedlings (10 cm <= height < 50 cm), and 2353 saplings (> 1 m tall). Watering significantly enhanced young seedling growth and survival, increasing stern density and diversity. Watering diminished the recruitment of species associated with upland forests, but increased the survival of both upland- and lowland-associated species. Though supplemental watering increased the growth of older seedlings. their density and diversity were unaffected. Sapling performance was insensitive to watering. We infer that variation in dry-season water availability may affect seedling community structure by differentially affecting recruitment and increasing overall survival. These results suggest that differential seedling recruitment and survival may contribute to the observed relationships between water availability, habitat associations and patterns of tree species richness.  
  Address [Paine, C. E. Timothy; Harms, Kyle E.] Louisiana State Univ, Dept Biol Sci, Baton Rouge, LA 70803 USA, Email: timothy.paine@ecofog.gf  
  Corporate Author Thesis  
  Publisher CAMBRIDGE UNIV PRESS Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0266-4674 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000264212400006 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 118  
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Author Dejean, A.; Grangier, J.; Leroy, C.; Orivel, J. openurl 
  Title Host plant protection by arboreal ants: looking for a pattern in locally induced responses Type Journal Article
  Year 2008 Publication Evolutionary Ecology Research Abbreviated Journal Evol. Ecol. Res.  
  Volume 10 Issue 8 Pages 1217-1223  
  Keywords aggressiveness; ant-plant relationships; Azteca; biotic defence; induced responses  
  Abstract Background: Among arboreal ants, both territorially dominant species and plant-ants (e.g. species associated with myrmecophytes or plants housing them in hollow structures) protect their host trees against defoliators. Yet, locally induced responses, or the recruitment of nest-mates when a worker discovers it wound on its host-tree, were only noted in plant-ants. We wondered whether this might be due to the examination of the phenomenon being restricted to only six plant-ant species belonging to four genera. Based on the ant genus Azteca, a Neotropical group of arboreal species, we compared five species. The territorially dominant, carton-nester A. chartifex, three plant-ant species [A. alfari and A. ovaticeps associated with myrmecophitic Cecropia (Cecropiaceae), and A. bequaerti associated with Tococa guianensis (Melastomataceae)], and A. schimperi thought to be a temporary social parasite of true Cecropia ants. Methods: We artificially inflicted wounds to the foliage of the host tree of the different ant species. We then compared the number of workers on wounded versus control leaves. Results: We noted a locally induced response in the three plant-ant species as well as in the territorially dominant species, but very slightly so in A. schimperi.  
  Address [Grangier, Julien; Orivel, Jerome] Univ Toulouse 2, Lab Evolut & Diversite Biol, CNRS, UMR 5174, Toulouse, France, Email: alain.dejean@wanadoo.fr  
  Corporate Author Thesis  
  Publisher EVOLUTIONARY ECOLOGY LTD Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1522-0613 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000264041000008 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 119  
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Author Phillips, O.L.; Aragao, L.E.O.C.; Lewis, S.L.; Fisher, J.B.; Lloyd, J.; Lopez-Gonzalez, G.; Malhi, Y.; Monteagudo, A.; Peacock, J.; Quesada, C.A.; van der Heijden, G.; Almeida, S.; Amaral, I.; Arroyo, L.; Aymard, G.; Baker, T.R.; Banki, O.; Blanc, L.; Bonal, D.; Brando, P.; Chave, J.; de Oliveira, A.C.A.; Cardozo, N.D.; Czimczik, C.I.; Feldpausch, T.R.; Freitas, M.A.; Gloor, E.; Higuchi, N.; Jimenez, E.; Lloyd, G.; Meir, P.; Mendoza, C.; Morel, A.; Neill, D.A.; Nepstad, D.; Patino, S.; Penuela, M.C.; Prieto, A.; Ramirez, F.; Schwarz, M.; Silva, J.; Silveira, M.; Thomas, A.S.; ter Steege, H.; Stropp, J.; Vasquez, R.; Zelazowski, P.; Davila, E.A.; Andelman, S.; Andrade, A.; Chao, K.J.; Erwin, T.; Di Fiore, A.; Honorio, E.; Keeling, H.; Killeen, T.J.; Laurance, W.F.; Cruz, A.P.; Pitman, N.C.A.; Vargas, P.N.; Ramirez-Angulo, H.; Rudas, A.; Salamao, R.; Silva, N.; Terborgh, J.; Torres-Lezama, A. openurl 
  Title Drought Sensitivity of the Amazon Rainforest Type Journal Article
  Year 2009 Publication Science Abbreviated Journal Science  
  Volume 323 Issue 5919 Pages 1344-1347  
  Keywords  
  Abstract Amazon forests are a key but poorly understood component of the global carbon cycle. If, as anticipated, they dry this century, they might accelerate climate change through carbon losses and changed surface energy balances. We used records from multiple long-term monitoring plots across Amazonia to assess forest responses to the intense 2005 drought, a possible analog of future events. Affected forest lost biomass, reversing a large long-term carbon sink, with the greatest impacts observed where the dry season was unusually intense. Relative to pre-2005 conditions, forest subjected to a 100-millimeter increase in water deficit lost 5.3 megagrams of aboveground biomass of carbon per hectare. The drought had a total biomass carbon impact of 1.2 to 1.6 petagrams (1.2 x 10(15) to 1.6 x 10(15) grams). Amazon forests therefore appear vulnerable to increasing moisture stress, with the potential for large carbon losses to exert feedback on climate change.  
  Address [Phillips, Oliver L.; Lewis, Simon L.; Lloyd, Jon; Lopez-Gonzalez, Gabriela; Peacock, Julie; Quesada, Carlos A.; van der Heijden, Geertje; Baker, Tim R.; Feldpausch, Ted R.; Gloor, Emanuel; Patino, Sandra; Schwarz, Michael; Chao, Kuo-Jung; Keeling, Helen] Univ Leeds, Sch Geog, Leeds LS2 9JT, W Yorkshire, England, Email: o.phillips@leeds.ac.uk  
  Corporate Author Thesis  
  Publisher AMER ASSOC ADVANCEMENT SCIENCE Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000263876700042 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 120  
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Author Fortunel, C.; Garnier, E.; Joffre, R.; Kazakou, E.; Quested, H.; Grigulis, K.; Lavorel, S.; Ansquer, P.; Castro, H.; Cruz, P.; Dolezal, J.; Eriksson, O.; Freitas, H.; Golodets, C.; Jouany, C.; Kigel, J.; Kleyer, M.; Lehsten, V.; Leps, J.; Meier, T.; Pakeman, R.; Papadimitriou, M.; Papanastasis, V.P.; Quetier, F.; Robson, M.; Sternberg, M.; Theau, J.P.; Thebault, A.; Zarovali, M. openurl 
  Title Leaf traits capture the effects of land use changes and climate on litter decomposability of grasslands across Europe Type Journal Article
  Year 2009 Publication Ecology Abbreviated Journal Ecology  
  Volume 90 Issue 3 Pages 598-611  
  Keywords climate; community functional parameters; disturbance; leaf traits; litter decomposability; litter quality  
  Abstract Land use and climate changes induce shifts in plant functional diversity and community structure, thereby modifying ecosystem processes. This is particularly true for litter decomposition, an essential process in the biogeochemical cycles of carbon and nutrients. In this study, we asked whether changes in functional traits of living leaves in response to changes in land use and climate were related to rates of litter potential decomposition, hereafter denoted litter decomposability, across a range of 10 contrasting sites. To disentangle the different control factors on litter decomposition, we conducted a microcosm experiment to determine the decomposability under standard conditions of litters collected in herbaceous communities from Europe and Israel. We tested how environmental factors ( disturbance and climate) affected functional traits of living leaves and how these traits then modified litter quality and subsequent litter decomposability. Litter decomposability appeared proximately linked to initial litter quality, with particularly clear negative correlations with lignin-dependent indices ( litter lignin concentration, lignin : nitrogen ratio, and fiber component). Litter quality was directly related to community-weighted mean traits. Lignin-dependent indices of litter quality were positively correlated with community-weighted mean leaf dry matter content (LDMC), and negatively correlated with community-weighted mean leaf nitrogen concentration (LNC). Consequently, litter decomposability was correlated negatively with community-weighted mean LDMC, and positively with community-weighted mean LNC. Environmental factors ( disturbance and climate) influenced community-weighted mean traits. Plant communities experiencing less frequent or less intense disturbance exhibited higher community-weighted mean LDMC, and therefore higher litter lignin content and slower litter decomposability. LDMC therefore appears as a powerful marker of both changes in land use and of the pace of nutrient cycling across 10 contrasting sites.  
  Address [Fortunel, Claire; Garnier, Eric; Joffre, Richard; Kazakou, Elena] CNRS, UMR 5175, Ctr Ecol Fonct & Evolut, F-34293 Montpellier 5, France, Email: claire.fortunel@ecofog.gf  
  Corporate Author Thesis  
  Publisher ECOLOGICAL SOC AMER Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0012-9658 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000263776800003 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 121  
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Author Ruelle, J.; Yamamoto, H.; Thibaut, B. openurl 
  Title Growth Stresses and Cellulose Structural Parameters in Tension and Normal Wood from Three Tropical Rainforest Angiosperm Species Type Journal Article
  Year 2007 Publication BioResources Abbreviated Journal BioResources  
  Volume 2 Issue 2 Pages 235-251  
  Keywords Cellulose; Microfibril angle; Crystallite size; Tension wood; Tropical rainforest; Growth stresses  
  Abstract Few studies have been conducted about relation between cellulose parameters and biomechanical properties of wood in tropical angiosperms species. For this purpose, on 13 trees from 3 species of French Guyana tropical rainforest in a clear active process of restoring verticality, i) growth strains were measured in situ in order to determine the occurrence of tension wood within samples and ii) cellulose structural parameters were estimated on all the samples using X-ray diffraction method. Crystallite size was estimated from the full-width at half-maximum of the Miller index (002) arc diffraction and angle T was measured following Cave's method. Relationships between these parameters and growth stresses were good and the variations between normal and tension wood were significant, i. e. a lower angle T and a larger crystallite size in tension wood. In order to have a good estimation of the microfibril angle in the main layer of the secondary wall for each species, an experimental calibration was done between angle T and microfibril angle observed with scanning electron microscopy.  
  Address [Ruelle, Julien; Thibaut, Bernard] UMR EcoFoG, Kourou 97387, Guyana, Email: ruelle_j@kourou.cirad.fr  
  Corporate Author Thesis  
  Publisher NORTH CAROLINA STATE UNIV DEPT WOOD & PAPER SCI Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1930-2126 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000263689300009 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 122  
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Author Almeras, T.; Fournier, M. openurl 
  Title Biomechanical design and long-term stability of trees: Morphological and wood traits involved in the balance between weight increase and the gravitropic reaction Type Journal Article
  Year 2009 Publication Journal of Theoretical Biology Abbreviated Journal J. Theor. Biol.  
  Volume 256 Issue 3 Pages 370-381  
  Keywords Mechanical design; Gravitropism; Bending stresses; Allometry; Reaction wood  
  Abstract Studies on tree biomechanical design usually focus on stem stiffness, resistance to breakage or uprooting, and elastic stability. Here we consider another biomechanical constraint related to the interaction between growth and gravity. Because stems are slender structures and are never perfectly symmetric, the increase in tree mass always causes bending movements. Given the current mechanical design of trees, integration of these movements over time would ultimately lead to a weeping habit unless some gravitropic correction occurs. This correction is achieved by asymmetric internal forces induced during the maturation of new wood. The long-term stability of a growing stem therefore depends on how the gravitropic correction that is generated by diameter growth balances the disturbance due to increasing self weight. General mechanical formulations based on beam theory are proposed to model these phenomena. The rates of disturbance and correction associated with a growth increment are deduced and expressed as a function of elementary traits of stem morphology, cross-section anatomy and wood properties. Evaluation of these traits using previously published data shows that the balance between the correction and the disturbance strongly depends on the efficiency of the gravitropic correction, which depends on the asymmetry of wood maturation strain, eccentric growth, and gradients in wood stiffness. By combining disturbance and correction rates, the gravitropic performance indicates the dynamics of stem bending during growth. It depends on stem biomechanical traits and dimensions. By analyzing dimensional effects, we show that the necessity for gravitropic correction might constrain stem allometric growth in the long-term. This constraint is compared to the requirement for elastic stability, showing that gravitropic performance limits the increase in height of tilted stem and branches. The performance of this function may thus limit the slenderness and lean of stems, and therefore the ability of the tree to capture light in a heterogeneous environment. (c) 2008 Elsevier Ltd. All rights reserved.  
  Address [Almeras, T.; Fournier, M.] INRA, UMR Ecol Forets Guyane, F-97310 Kourou, France, Email: t_almeras@hotmail.com  
  Corporate Author Thesis  
  Publisher ACADEMIC PRESS LTD ELSEVIER SCIENCE LTD Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0022-5193 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000263077100008 Approved no  
  Call Number (up) EcoFoG @ eric.marcon @ Serial 123  
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