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Author Nicolini, E.; Caraglio, Y.; Pelissier, R.; Leroy, C.; Roggy, J.C. openurl 
  Title Epicormic branches: a growth indicator for the tropical forest tree, Dicorynia guianensis Amshoff (Caesalpiniaceae) Type Journal Article
  Year 2003 Publication Annals of Botany Abbreviated Journal Ann. Bot.  
  Volume 92 Issue 1 Pages 97-105  
  Keywords (down) Dicorynia guianensis; architecture; epicormic branch; primary growth; secondary growth; tropical forest; French Guiana; height : diameter ratio  
  Abstract Architectural analyses of temperate tree species using a chronological approach suggest that the expression of epicormic branches is closely related to low growth rates in the axes that make up the branching system. Therefore, sole consideration of epicormic criteria may be sufficient to identify trees with low secondary growth levels or with both low primary and secondary growth levels. In a tropical tree such as Dicorynia guianensis (basralocus), where chronological studies are difficult, this relationship could be very useful as an easily accessible indicator of growth potentials. A simple method of architectural tree description was used to characterize the global structure of more than 1650 basralocus trees and to evaluate their growth level. Measurements of simple growth characters [height, basal diameter, internode length of submittal part (top of the main axis of the tree)] and the observation of four structural binary descriptors on the main stem (presence of sequential branches and young epicormic branches, state of the submittal part, global orientation), indicated that epicormic branch formation is clearly related to a decrease in length of the successive growth units of the main stem. Analysis of height vs. diameter ratios among different tree subgroups, with and without epicormic branching, suggested that trees with epicormic branches generally have a low level of secondary growth compared with primary growth. (C) 2003 Annals of Botany Company.  
  Address Cirad, UMR AMAP, F-34398 Montpellier 05, France  
  Corporate Author Thesis  
  Publisher OXFORD UNIV PRESS Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0305-7364 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000183980200010 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 245  
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Author Amusant, N.; Beauchene, J.; Fournier, M.; Janin, G.; Thevenon, M.F. openurl 
  Title Decay resistance in Dicorynia guianensis Amsh.: analysis of inter-tree and intra-tree variability and relations with wood colour Type Journal Article
  Year 2004 Publication Annals of Forest Science Abbreviated Journal Ann. For. Sci.  
  Volume 61 Issue 4 Pages 373-380  
  Keywords (down) Dicorynia guianensis; Amazonian wood; wood colour/decay resistance; heartwood; variability  
  Abstract Dicorynia guianensis Amsh. is very widespread in the forests of French Guiana and moreover is the leading species harvested in this area, but its main defect remains the great variability of wood durability, especially with respect to fungal decay. The aim of this work was to study this inter- and intra-tree variability in order to identify the parameters responsible for this variation (growth area, height and radial position) within the tree. The resistance decrease from the outer heartwood to the pith. Measurement of colour variation using the CIELAB (L*, a*, b*, C*, h*) system was performed at the intra-tree level to highlight the longitudinal and radial gradients of variation. Dicorynia guianensis becomes less red and dark from the outer to the inner heartwood and from the base to the top. Lastly, variations of colour and durability were correlated: the wood is less resistant the redder and darker it is.  
  Address CIRAD Foret, Forest Prod Programme, F-34398 Montpellier 5, France, Email: nadine.amusant@cirad.fr  
  Corporate Author Thesis  
  Publisher E D P SCIENCES Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1286-4560 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000223955500009 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 262  
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Author Roux, O.; Le Lann, C.; van Alphen, J.J.M.; van Baaren, J. openurl 
  Title How does heat shock affect the life history traits of adults and progeny of the aphid parasitoid Aphidius avenae (Hymenoptera: Aphidiidae)? Type Journal Article
  Year 2010 Publication Bulletin of Entomological Research Abbreviated Journal Bull. Entomol. Res.  
  Volume 100 Issue 5 Pages 543-549  
  Keywords (down) developmental rate; fecundity; heat stress; longevity; sex-specific effect; parasitic wasp  
  Abstract Because insects are ectotherms, their physiology, behaviour and fitness are influenced by the ambient temperature. Any changes in environmental temperatures may impact the fitness and life history traits of insects and, thus, affect population dynamics. Here, we experimentally tested the impact of heat shock on the fitness and life history traits of adults of the aphid parasitoid Aphidius avenae and on the later repercussions for their progeny. Our results show that short exposure (1h) to an elevated temperature (36 degrees C), which is frequently experienced by parasitoids during the summer, resulted in high mortality rates in a parasitoid population and strongly affected the fitness of survivors by drastically reducing reproductive output and triggering a sex-dependent effect on lifespan. Heat stress resulted in greater longevity in surviving females and in shorter longevity in surviving males in comparison with untreated individuals. Viability and the developmental rates of progeny were also affected in a sex-dependent manner. These results underline the ecological importance of the thermal stress response of parasitoid species, not only for survival, but also for maintaining reproductive activities.  
  Address [Roux, O.] Univ Toulouse 3, Lab Ecol Fonct, UMR 5245 CNRS UPS INPT, F-31062 Toulouse 04, France, Email: oroux@cict.fr  
  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 0007-4853 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000282077700005 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 42  
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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 Tree Physiology Abbreviated Journal Tree Physiol.  
  Volume 25 Issue 12 Pages 1545-1552  
  Keywords (down) 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 Abedini, R.; Clair, B.; Pourtahmasi, K.; Laurans, F.; Arnould, O. url  openurl
  Title Cell wall thickening in developing tension wood of artificially bent poplar trees Type Journal Article
  Year 2015 Publication IAWA Journal Abbreviated Journal IAWA Journal  
  Volume 36 Issue 1 Pages 44-57  
  Keywords (down) developing xylem; Gelatinous layer; maturation stress; secondary wall layer; tree biomechanics  
  Abstract Trees can control their shape and resist gravity thanks to their ability to produce wood under tensile stress. This stress is known to be produced during the maturation of wood fibres but the mechanism of its generation remains unclear. This study focuses on the formation of the secondary wall in tension wood produced in artificially tilted poplar saplings. Thickness of secondary wall layer (SL) and gelatinous layer (GL) were measured from cambium to mature wood in several trees sampled at different times after tilting. Measurements on wood fibres produced before tilting show the progressive increase of secondary wall thickness during the growing season. After the tilting date, SL thickness decreased markedly from normal wood to tension wood while the total thickness increased compared to normal wood, with the development of a thick GL. However, even after GL formation, SL thickness continues to increase during the growing season. GL thickening was observed to be faster than SL thickening. The development of the unlignified GL is proposed to be a low cost, efficient strategy for a fast generation of tensile stress in broadleaved trees. © 2015 International Association of Wood Anatomists.  
  Address INRA, UR588 Amélioration, Génétique et Physiologie ForestièresOrléans, France  
  Corporate Author Thesis  
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  Notes Export Date: 17 April 2015 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 596  
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Author Stahl, C.; Herault, B.; Rossi, V.; Burban, B.; Bréchet, C.; Bonal, D. url  openurl
  Title Depth of soil water uptake by tropical rainforest trees during dry periods: Does tree dimension matter? Type Journal Article
  Year 2013 Publication Oecologia Abbreviated Journal Oecologia  
  Volume 173 Issue 4 Pages 1191-1201  
  Keywords (down) Deuterium; Oxygen; Root; Soil water; Tropical rainforest  
  Abstract Though the root biomass of tropical rainforest trees is concentrated in the upper soil layers, soil water uptake by deep roots has been shown to contribute to tree transpiration. A precise evaluation of the relationship between tree dimensions and depth of water uptake would be useful in tree-based modelling approaches designed to anticipate the response of tropical rainforest ecosystems to future changes in environmental conditions. We used an innovative dual-isotope labelling approach (deuterium in surface soil and oxygen at 120-cm depth) coupled with a modelling approach to investigate the role of tree dimensions in soil water uptake in a tropical rainforest exposed to seasonal drought. We studied 65 trees of varying diameter and height and with a wide range of predawn leaf water potential (Ψpd) values. We confirmed that about half of the studied trees relied on soil water below 100-cm depth during dry periods. Ψpd was negatively correlated with depth of water extraction and can be taken as a rough proxy of this depth. Some trees showed considerable plasticity in their depth of water uptake, exhibiting an efficient adaptive strategy for water and nutrient resource acquisition. We did not find a strong relationship between tree dimensions and depth of water uptake. While tall trees preferentially extract water from layers below 100-cm depth, shorter trees show broad variations in mean depth of water uptake. This precludes the use of tree dimensions to parameterize functional models. © 2013 Springer-Verlag Berlin Heidelberg.  
  Address INRA, UMR EEF 1137, 54280 Champenoux, France  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
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  ISSN 00298549 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Export Date: 6 December 2013; Source: Scopus; Coden: Oecob; doi: 10.1007/s00442-013-2724-6; Language of Original Document: English; Correspondence Address: Bonal, D.; INRA, UMR EEF 1137, 54280 Champenoux, France; email: bonal@nancy.inra.fr; References: Améglio, T., Archer, P., Cohen, M., Valancogne, C., Daudet, F.A., Dayau, S., Cruiziat, P., Significance and limits in the use of predawn leaf water potential for tree irrigation (1999) Plant Soil, 207, pp. 155-167; Baraloto, C., Morneau, F., Bonal, D., Blanc, L., Ferry, B., Seasonal water stress tolerance and habitat associations within four Neotropical tree genera (2007) Ecology, 88, pp. 478-489; Bonal, D., Barigah, T.S., Granier, A., Guehl, J.-M., Late-stage canopy tree species with extremely low delta C-13 and high stomatal sensitivity to seasonal soil drought in the tropical rainforest of French Guiana (2000) Plant Cell Environ, 23, pp. 445-459; Bonal, D., Atger, C., Barigah, T.S., Ferhi, A., Guehl, J.-M., Ferry, B., Water acquisition patterns of two wet tropical canopy tree species of French Guiana as inferred from H218O extraction profiles (2000) Ann For Sci, 57, pp. 717-724; Bonal, D., Bosc, A., Ponton, S., Goret, J.-Y., Burban, B., Gross, P., Bonnefond, J.-M., Granier, A., Impact of severe dry season on net ecosystem exchange in the Neotropical rainforest of French Guiana (2008) Glob Chang Biol, 14, pp. 1917-1933; Cao, K.F., Water relations and gas exchange of tropical saplings during a prolonged drought in a Bornean heath forest, with reference to root architecture (2000) J Trop Ecol, 16, pp. 101-116; Carvalheiro, K.O., Nepstad, D.C., Deep soil heterogeneity and fine root distribution in forests and pastures of eastern Amazonia (1996) Plant Soil, 182, pp. 279-285; Chmura, D.J., Anderson, P.D., Howe, G.T., Harrington, C.A., Halofsky, J.E., Peterson, D.L., Shaw, D.C., Brad St Claire, J., Forest responses to climate change in the northwestern United States: ecophysiological foundations for adaptive management (2011) For Ecol Manage, 261, pp. 1121-1142; da Rocha, H.R., Goulden, M.L., Miller, S.D., Menton, M.C., Pinto, L.D.V.O., de Freitas, H.C., e Silva Figueira, A.M., Seasonality of water and heat fluxes over a tropical forest in eastern Amazonia (2004) Ecol Appl, 14, pp. 22-32; Davidson, E., Lefebvre, P.A., Brando, P.M., Ray, D.M., Trumbore, S.E., Solorzano, L.A., Ferreira, J.N., Nepstad, D.C., Carbon inputs and water uptake in deep soils of an eastern Amazon forest (2011) For Sci, 57, pp. 51-58; Engelbrecht, B.M.J., Kursar, T.A., Comparative drought-resistance of seedlings of 28 species of co-occurring tropical woody plants (2003) Oecologia, 136, pp. 383-393; Engelbrecht, B.M.J., Wright, S.J., De Steven, D., Survival and ecophysiology of tree seedlings during El Nino drought in a tropical moist forest in Panama (2002) J Trop Ecol, 18, pp. 569-579; Fisher, R.A., Williams, M., Do Vale, R.L., Da Costa, A.L., Meir, P., Evidence from Amazonian forests is consistent with isohydric control of leaf water potential (2006) Plant Cell Environ, 29, pp. 151-165; Goulden, M.L., Miller, S.D., da Rocha, H.R., Menton, M.C., De Freitas, H.C., Silva Figueira, A.M.E., De Sousa, C.A.D., Diel and seasonal patterns of tropical forest CO2 exchange (2004) Ecol Appl, 14, pp. 42-54; Gourlet-Fleury, S., Ferry, B., Molino, J.F., Petronelli, P., Schmitt, L., Experimental plots: key features (2004) Ecology and management of a Neotropical Rainforest, pp. 3-60. , In: Gourlet-Fleury S, Guehl JM, Laroussinie O (eds) Lessons drawn from Paracou, a long-term experimental research site in French Guiana. Elsevier, Paris; Huc, R., Ferhi, A., Guehl, J.M., Pioneer and late stage tropical rainforest tree species (French Guyana) growing under common conditions differ in leaf gas exchange regulation, carbon isotope discrimination and leaf water potential (1994) Oecologia, 99, pp. 297-305; Hutyra, L.R., Munger, J.W., Saleska, S., Gottlieb, E., Daube, B.C., Dunn, A.L., Amaral, D.F., Wofsy, S.C., Seasonal controls on the exchange of carbon and water in an Amazonian rain forest (2007) J Geophys Res, 112, pp. G03008. , doi:10.1029/2006JG000365; Jackson, R.B., Canadell, J., Ehleringer, J.R., Mooney, H.A., Sala, O.E., Schulze, E.D., A global analysis of root distributions for terrestrial biomes (1996) Oecologia, 108, pp. 389-411; Jobbagy, E.G., Jackson, R.B., The distribution of soil nutrients with depth: global patterns and the imprint of plants (2001) Biogeochemistry, 53, pp. 51-77; Kozlowski, T.T., Pallardy, S.G., Acclimation and adaptive responses of woody plants to environmental stresses (2002) Bot Rev, 68, pp. 270-334; Malhi, Y., Wright, J., Spatial patterns and recent trends in the climate of tropical rainforest regions (2004) Phil Trans R Soc Lond B, 359, pp. 311-329; Markewitz, D., Devine, S., Davidson, E.A., Brando, P., Nepstad, D.C., Soil moisture depletion under simulated drought in the Amazon: impacts on deep root uptake (2010) New Phytol, 187, pp. 592-607; Meinzer, F.C., Andrade, J.L., Goldstein, G., Holbrook, N.M., Cavelier, J., Wright, S.J., Partitioning of soil water among trees in a seasonally dry tropical forest (1999) Oecologia, 121, pp. 293-301; Merbold, L., Ardo, J., Arneth, A., Scholes, R.J., Nouvellon, Y., de Grandcourt, A., Archibald, S., Kutsch, W.L., Precipitation as driver of carbon fluxes in 11 African ecosystems (2009) Biogeosciences, 6, pp. 1027-1041; Moreira, M., Sternberg, L., Nepstad, D., Vertical patterns of soil water uptake by plants in a primary forest and an abandoned pasture in the eastern Amazon: an isotopic approach (2000) Plant Soil, 222, pp. 95-107; Nepstad, D.C., De Carvalho, C.R., Davidson, E.A., Jipp, P.H., Lefebvre, P.A., Negreiros, G.H., Da Silva, E.D., Vieira, S., The role of deep roots in the hydrological and carbon cycles of Amazonian forests and pastures (1994) Nature, 372, pp. 666-669; Oliveira, R., Dawson, T., Burgess, S., Nepstad, D., Hydraulic redistribution in three Amazonian trees (2005) Oecologia, 145, pp. 354-363; Poorter, L., Markesteijn, L., Seedling traits determine drought tolerance of tropical tree species (2008) Biotropica, 40, pp. 321-331; (2010) R: A Language and Environment for Statistical Computing, , R Development Core Team, Vienna: R Foundation for Statistical Computing; Romero-Saltos, H., LdSL, S., Moreira, M.Z., Nepstad, D.C., Rainfall exclusion in an eastern Amazonian forest alters soil water movement and depth of water uptake (2005) Am J Bot, 92, pp. 443-455; Sobrado, M.A., Embolism vulnerability in drought-deciduous and evergreen species of a tropical dry forest (1997) Acta Oecol, 18, pp. 383-391; Stahl, C., Burban, B., Bompy, F., Jolin, Z.B., Sermage, J., Bonal, D., Seasonal variation in atmospheric relative humidity contributes to explaining seasonal variation in trunk circumference of tropical rain-forest trees in French Guiana (2010) J Trop Ecol, 26, pp. 393-405; Stahl, C., Burban, B., Goret, J.-Y., Bonal, D., Seasonal variations in stem CO2 efflux in the Neotropical rainforest of French Guiana (2011) Ann For Sci, 68, pp. 771-782; Stahl, C., Burban, B., Wagner, F., Goret, J.-Y., Bompy, F., Bonal, D., Influence of seasonal variations in soil water availability on gas exchange of tropical canopy trees (2013) Biotropia, 45, pp. 155-164; Sternberg, L., Green, L., Moreira, M.Z., Nepstad, D.C., Martinelli, L.A., Victoria, R., Root distribution in an Amazonian seasonal forest (1998) Plant Soil, 205, pp. 45-50; Sternberg, L., Moreira, M., Nepstad, D.C., Uptake of water by lateral roots of small trees in an Amazonian tropical forest (2002) Plant Soil, 238, pp. 151-158; Wagner, F., Hérault, B., Stahl, C., Bonal, D., Rossi, V., Modeling water availability for trees in tropical forests (2011) Agric For Meteorol, 151, pp. 1202-1213; Wagner, F., Rossi, V., Stahl, C., Bonal, D., Hérault, B., Water availability is the main climate driver of Neotropical tree growth (2012) PLoS ONE, 7, pp. e34074; Wang, G., Alo, C., Mei, R., Sun, S., Droughts, hydraulic redistribution, and their impact on vegetation composition in the Amazon forest (2011) Plant Ecol, 212, pp. 663-673; Williams, M., Malhi, Y., Nobre, A.D., Rastetter, E.B., Grace, J., Pereira, M.G.P., Seasonal variation in net carbon exchange and evapotranspiration in a Brazilian rainforest: a modelling analysis (1998) Plant Cell Environ, 21, pp. 953-968; Yavitt, J.B., Wright, S.J., Drought and irrigation effects on fine root dynamics in a tropical moist forest, Panama (2001) Biotropica, 33, pp. 421-434; Zapater, M., Hossann, C., Bréda, N., Bréchet, C., Bonal, D., Granier, A., Evidence of hydraulic lift in a young beech and oak mixed forest using 18O soil water labelling (2011) Trees Struct Funct, 25, pp. 885-894; Zhang, Y., Tan, Z., Song, Q., Yu, G., Sun, X., Respiration controls the unexpected seasonal pattern of carbon flux in an Asian tropical rain forest (2010) Atmos Environ, 44, pp. 3886-3893 Approved no  
  Call Number EcoFoG @ webmaster @ Serial 514  
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Author Tysklind, N.; Etienne, M.-P.; Scotti-Saintagne, C.; Tinaut, A.; Casalis, M.; Troispoux, V.; Cazal, S.-O.; Brousseau, L.; Ferry, B.; Scotti, I. doi  openurl
  Title Microgeographic local adaptation and ecotype distributions: The role of selective processes on early life-history traits in sympatric, ecologically divergent Symphonia populations Type Journal Article
  Year 2020 Publication Ecology and Evolution Abbreviated Journal Ecology and Evolution  
  Volume 10 Issue 19 Pages 10735-10753  
  Keywords (down) determinants of plant community diversity and structure; evolutionary ecology; landscape ecology; local adaptation; Neotropical forest; plant development and life-history traits; reciprocal transplantation experiments; Symphonia  
  Abstract Trees are characterized by the large number of seeds they produce. Although most of those seeds will never germinate, plenty will. Of those which germinate, many die young, and eventually, only a minute fraction will grow to adult stage and reproduce. Is this just a random process? Do variations in germination and survival at very young stages rely on variations in adaptations to microgeographic heterogeneity? and do these processes matter at all in determining tree species distribution and abundance?. We have studied these questions with the Neotropical Symphonia tree species. In the Guiana shield, Symphonia are represented by at least two sympatric taxa or ecotypes, Symphonia globulifera found almost exclusively in bottomlands, and a yet undescribed more generalist taxon/ecotype, Symphonia sp1. A reciprocal transplantation experiment (510 seeds, 16 conditions) was set up and followed over the course of 6 years to evaluate the survival and performance of individuals from different ecotypes and provenances. Germination, survival, growth, and herbivory showed signs of local adaptation, with some combinations of ecotypes and provenances growing faster and surviving better in their own habitat or provenance region. S. globulifera was strongly penalized when planted outside its home habitat but showed the fastest growth rates when planted in its home habitat, suggesting it is a specialist of a high-risk high-gain strategy. Conversely, S. sp1 behaved as a generalist, performing well in a variety of environments. The differential performance of seeds and seedlings in the different habitats matches the known distribution of both ecotypes, indicating that environmental filtering at the very early stages can be a key determinant of tree species distributions, even at the microgeographic level and among very closely related taxa. Furthermore, such differential performance also contributes to explain, in part, the maintenance of the different Symphonia ecotypes living in intimate sympatry despite occasional gene flow. © 2020 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd  
  Address UMR AMAP, IRD, Cirad, CNRS, INRAE, Université Montpellier, Montpellier, France  
  Corporate Author Thesis  
  Publisher John Wiley and Sons Ltd Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 20457758 (Issn) ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number EcoFoG @ webmaster @ Serial 951  
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Author Pierrejean, I.; Mehinto, T.; Beauchene, J. url  openurl
  Title Comparative Analysis of Three Different Methods Used to Determine the Elastic Modulus for a Choice of Tropical Guianese Wood Species Type Journal Article
  Year 2017 Publication Pro Ligno Abbreviated Journal  
  Volume 13 Issue 1 Pages 3-17  
  Keywords (down) density; modulus of elasticity; static and dynamic tests; tropical woods  
  Abstract This study compares variability in the longitudinal Modulus of Elasticity (MOE) values, measured by three different methods, for eight tropical wood species covering a wide range of densities, a property that has been little described in the literature for some of the species studied. The modulus of elasticity in wood species is one of the main mechanical properties measured to characterize wood materials. However, this property is seldom described for the tropical wood species studied here, and the method used is often variable. The aim is to answer the following questions. In the methods used, what are the main variability factors which influence modulus measurement? Is the modulus different with regard to the solicitation direction (radial or tangential)? Which relationship exists between modulus and density for these species?
The samples were subjected to the four-point bending test, then to the free vibration test and to the forced-vibration test (which allows tests on small samples).The samples were subjected to stress in radial and tangential directions. The modulus values obtained by the different methods were well correlated for most of the species. The relationship between modulus and density was very good at inter-specific level because sampling covered a wide range of densities. But this relationship was not so good for each of the species sampled.
This kind of test was not appropriate for detecting differences in behavior between the two directions of solicitation for these species. The main features of the three methods were summarized, highlighting the advantages of each for the species studied.
 
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  Call Number EcoFoG @ webmaster @ Serial 753  
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Author Fromin, N.; Saby, N.P.A.; Lensi, R.; Brunet, D.; Porte, B.; Domenach, A.-M.; Roggy, J.-C. url  doi
openurl 
  Title Spatial variability of soil microbial functioning in a tropical rainforest of French Guiana using nested sampling Type Journal Article
  Year 2013 Publication Geoderma Abbreviated Journal  
  Volume 197-198 Issue Pages 98-107  
  Keywords (down) Denitrification; Respiration; Scale dependent process; Soil microbial processes; Soil organic matter; Tree influence potential  
  Abstract Understanding the pattern in spatial distribution of soil microbial processes is critical to understand the environmental factors that regulate them as well as to scale up these processes to ecosystem. Soil samples from a 1. ha tropical rainforest plot (Paracou, French Guiana) were analyzed according a nested sampling approach using different separation distances ranging from 0.4 to 40. m. The variability of substrate induced respiration (SIR) and of denitrification enzyme activity (DEA) was characterized in relation to various soil properties (total C and N contents, NIRS related index of soil organic matter quality, SOMQ, and index of tree influence potential, IP). The variability of SIR and DEA was higher than that of environmental properties. The patterns of accumulated variance as a function of distance varied among the soil properties. The variability of SIR and DEA mainly occurred at small (1. m) scale (and at the 10-40. m-scales for SIR), probably reflecting the quality of litter input that results of the influence of local assemblage of different tree species, though changes in the soil N and C contents. Indeed, total soil C and N contents explained the microbial properties at every scale. Coefficients of codispersion showed that neither SOMQ nor IP did correlate with SIR and DEA, and confirmed that total C and N contents explained microbial properties in a scale dependent and complex manner. Such spatial dependency underlines the importance of soil heterogeneity in this tropical forest with implications for sampling strategies when studying the microbial processes and their response to disturbances. © 2012 Elsevier B.V.  
  Address UMR EcoFoG, BP 709, 97387 Kourou, GUF, France  
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  Notes Export Date: 13 February 2013; Source: Scopus Approved no  
  Call Number EcoFoG @ webmaster @ Serial 466  
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Author Degen, B.; Blanc, L.; Caron, H.; Maggia, L.; Kremer, A.; Gourlet-Fleury, S. openurl 
  Title Impact of selective logging on genetic composition and demographic structure of four tropical tree species Type Journal Article
  Year 2006 Publication Biological Conservation Abbreviated Journal Biol. Conserv.  
  Volume 131 Issue 3 Pages 386-401  
  Keywords (down) demography; genetic diversity; logging; phenology; pollen and seed dispersal; simulation; trees; tropics  
  Abstract Over-exploitation and fragmentation are serious problems for tropical forests. Most sustainable forest management practices avoid clear-cuts and apply selective logging systems focused on a few commercial species. We applied a simulation model to estimate the impact of such selective logging scenarios on the genetic diversity and demography of four tropical tree species from French Guiana. The simulations used data on genetic and demographic composition, growth, phenology and pollen and seed dispersal obtained for Dicorynia guianensis, Sextonia rubra, Symphonia globulifera and Vouacapoua americana at the experimental site in Paracou. Whereas Symphonia globulifera serves as a model for a species with low logging pressure, the other three species represent the most exploited tree species in French Guiana. In simulations with moderate logging, typical for French Guiana, with large cutting diameter (> 60 cm diameter) and long cutting cycles (65 years), the two species V. americana and Sextonia rubra were not able to recover their initial stock at the end of the rotation period, with a large decrease in the number of individuals and in basal area. Under a more intensive logging system (cutting diameter > 45 cm diameter, cutting cycles of 30 years) that is common practice in the Brazilian Amazon, only Symphonia globulifera showed no negative impact. Generally, the differences between the genetic parameters in the control scenarios without logging and the logging scenarios were surprisingly small. The main reasons for this were the overlapping of generations and the effective dispersal ability of gene vectors in all species, which guarantee relative homogeneity of the genetic structure in different age classes. Nevertheless, decreasing the population size by logging reduced the number of genotypes and caused higher genetic distances between the original population and the population at the end of the logging cycles. Sensitivity analysis showed that genetic changes in the logging scenarios were principally determined by the growth, densities and cutting diameter of each species, and only to a very small extent by the reproductive system including factors such as pollen and seed dispersal and flowering phenology. (c) 2006 Elsevier Ltd. All rights reserved.  
  Address BFH, Inst Forstgenet & Forstpflanzenzuchtung, D-22927 Grosshansdorf, Germany, Email: b.degen@holz.uni-hamburg.de  
  Corporate Author Thesis  
  Publisher ELSEVIER SCI LTD Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0006-3207 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000239139400004 Approved no  
  Call Number EcoFoG @ eric.marcon @ Serial 180  
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