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Author Brémaud, I.; Ruelle, J.; Thibaut, A.; Thibaut, B. doi  openurl
  Title Changes in viscoelastic vibrational properties between compression and normal wood: Roles of microfibril angle and of lignin Type Journal Article
  Year 2013 Publication Holzforschung Abbreviated Journal  
  Volume 67 Issue 1 Pages (up) 75-85  
  Keywords Compression wood (CW); Damping coefficient; Ft-Ir; Internal friction; Lignin; Microfibril angle (MFA); Picea abies; Pinus pinaster; Pinus sylvestris; Specific dynamic modulus of elasticity; Viscoelastic vibrational properties  
  Abstract This study aims at better understanding the respective influences of specific gravity (γ ), microfibril angle (MFA), and cell wall matrix polymers on viscoelastic vibrational properties of wood in the axial direction. The wide variations of properties between normal wood (NW) and compression wood (CW) are in focus. Three young bent trees (Picea abies, Pinus sylvestris and Pinus pinaster ), which recovered verticality, were sampled. Several observed differences between NW and CW were highly significant in terms of anatomical, physical (γ, shrinkage, CIE Lab colorimetry), mechanical (compressive strength), and vibrational properties. The specific dynamic modulus of elasticity (E′/γ) decreases with increasing MFA, and Young's modulus (E′) can be satisfactorily explained by γ and MFA. Apparently, the type of the cell wall polymer matrix is not influential in this regard. The damping coefficient (tan δ) does not depend solely on the MFA of NW and CW. The tanδ-E′/γ relationship evidences that, at equivalent E′/γ, the tan δ of CW is approximately 34% lower than that of NW. This observation is ascribed to the more condensed nature of CW lignins, and this is discussed in the context of previous findings in other hygrothermal and time/frequency domains. It is proposed that the lignin structure and the amount and type of extractives, which are both different in various species, are partly responsible for taxonomy-related damping characteristics. Copyright © by Walter de Gruyter • Berlin • Boston.  
  Address Wood Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland  
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  Notes Export Date: 25 February 2013; Source: Scopus Approved no  
  Call Number EcoFoG @ webmaster @ Serial 471  
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Author Bodin, S.C.; Scheel-Ybert, R.; Beauchene, J.; Molino, J.-F.; Bremond, L. url  doi
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  Title CharKey: An electronic identification key for wood charcoals of French Guiana Type Journal Article
  Year 2019 Publication IAWA Journal Abbreviated Journal Iawa J.  
  Volume 40 Issue 1 Pages (up) 75-91  
  Keywords anthracology; Charcoal anatomy; computeraided identification; Note: Supplementary material can be accessed in the online edition of this journal via brill.com/iawa.; tropical flora; Xper 2  
  Abstract Tropical tree floras are highly diverse and many genera and species share similar anatomical patterns, making the identification of tropical wood charcoal very difficult. Appropriate tools to characterize charcoal anatomy are thus needed to facilitate and improve identification in such species-rich areas. This paper presents the first computer-aided identification key designed for charcoals from French Guiana, based on the wood anatomy of 507 species belonging to 274 genera and 71 families, which covers respectively 28%, 67% and 86% of the tree species, genera and families currently listed in this part of Amazonia. Species of the same genus are recorded together except those described under a synonym genus in Détienne et al. (1982) that were kept separately. As a result, the key contains 289 'items' and mostly aims to identify charcoals at the genus level. It records 26 anatomical features leading to 112 feature states, almost all of which are illustrated by SEM photographs of charcoal. The descriptions were mostly taken from Détienne et al.'s guidebook on tropical woods of French Guiana (1982) and follow the IAWA list of microscopic features for hardwood identification (Wheeler et al. 1989). Some adjustments were made to a few features and those that are unrelated to charcoal identification were excluded. The whole tool, named CharKey, contains the key itself and the associated database including photographs. It can be downloaded on Figshare at https://figshare.com/s/d7d40060b53d2ad60389 (doi: 10.6084/m9.figshare.6396005). CharKey is accessible using the free software Xper 2 , specifically conceived for taxonomic description and computer aided-identification.  
  Address Ecole Pratique des Hautes Etudes, PSL Research University, Paris, France  
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  Publisher Brill Academic Publishers Place of Publication Editor  
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  ISSN 09281541 (Issn) ISBN Medium  
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  Call Number EcoFoG @ webmaster @ Serial 864  
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Author Baraloto, C.; Ferreira, E.; Rockwell, C.; Walthier, F. pdf  url
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  Title Limitations and Applications of Parataxonomy for Community Forest Management in Southwestern Amazonia Type Journal Article
  Year 2007 Publication Ethnobotany Research & Applications Abbreviated Journal  
  Volume 5 Issue Pages (up) 77-84  
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  Abstract We examined the limitations of parataxonomic inventories for developing management plans for woody plant resources in tropical rain forests of southwestern Amazonia. Using compilations of herbarium labels, forest personnel interviews and published species descriptions, we assessed the accuracy of common names as parataxonomic units (PUs). We identified 384 common names for 310 harvested woody plant species in the Brazilian state of Acre, of which only 50% were unique to a single taxonomic species. About 10% of common names referred to more than one species, more than half of which included multiple genera. For the 106 species from the Acre sample common to the MAP region including Madre de Dios, Peru and Pando, Bolivia, we identified 198 common names. Splitting was much more frequent in this sample, with more than 80% of species having more than one common name. When the Acre sample was expanded to 131 species from the Brazilian Amazon region, including the states of Amazonas and Para, we identified 740 common names, with nearly 90% of species being represented by more than one common name. Errors and inaccuracy of parataxonomy may contribute to market instability if product orders can not be homogenized within regional markets, and to unsustainable harvests if species are mistakenly lumped into single parataxonomic units. We discuss several programs currently being implemented by our collaborative team in the region to address this issue, including field guides based on digital photography, field courses, and workshops featuring discussions between regional inventory personnel and botanists.  
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  Notes 2008; Limitations and Applications of Parataxonomy for Community Forest Management in Southwestern Amazonia Approved no  
  Call Number EcoFoG @ eric.marcon @ 14 Serial 214  
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Author Dezerald, O.; Talaga, S.; Leroy, C.; Carrias, J.-F.; Corbara, B.; Dejean, A.; Céréghino, R. url  doi
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  Title Environmental determinants of macroinvertebrate diversity in small water bodies: Insights from tank-bromeliads Type Journal Article
  Year 2014 Publication Hydrobiologia Abbreviated Journal Hydrobiologia  
  Volume 723 Issue 1 Pages (up) 77-86  
  Keywords Freshwater biodiversity; Linear mixed effect modelling; Microcosms; Phytotelmata; Ponds  
  Abstract The interlocking leaves of tank-forming bromeliads (Bromeliaceae) collect rainwater and detritus, thus creating a freshwater habitat for specialized organisms. Their abundance and the possibility of quantifying communities with accuracy give us unparalleled insight into how changes in local to regional environments influence community diversity in small water bodies. We sampled 365 bromeliads (365 invertebrate communities) along a southeastern to northwestern range in French Guiana. Geographic locality determined the species pool for bromeliad invertebrates, and local environments determined the abundance patterns through the selection of traits that are best adapted to the bromeliad habitats. Patterns in community structure mostly emerged from patterns of predator species occurrence and abundance across local-regional environments, while the set of detritivores remained constant. Water volume had a strong positive correlation with invertebrate diversity, making it a biologically relevant measure of the pools' carrying capacity. The significant effects of incoming detritus and incident light show that changes in local environments (e.g., the conversion of forest to cropping systems) strongly influence freshwater communities. Because changes in local environments do not affect detritivores and predators equally, one may expect functional shifts as sets of invertebrates with particular traits are replaced or complemented by other sets with different traits. © 2013 Springer Science+Business Media Dordrecht.  
  Address CNRS, EcoLab (UMR-CNRS 5245), 118 Route de Narbonne, 31062 Toulouse, France  
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  ISSN 00188158 (Issn) ISBN Medium  
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  Call Number EcoFoG @ webmaster @ Serial 517  
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Author Seibold, Sebastien ; Rammer, Werner ; Hothorn, Torsten ; Seidl, Rupert ; Ulyshen, Michael ; Lorz, Janina ; Cadotte, Marc ; Lindenmayer, David ; Adhikari, Yagya ; Aragón, Roxana ; Bae, Soyeon ; Baldrian, Petr ; Barimani Varandi, Hassan ; Barlow, Jos ; Bässler, Clauss ; Beauchêne, Jacques ; and all ................... doi  openurl
  Title The contribution of insects to global forest deadwood decomposition Type Journal Article
  Year 2021 Publication Nature Abbreviated Journal  
  Volume 597 Issue 7874 Pages (up) 77-81  
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  Abstract The amount of carbon stored in deadwood is equivalent to about 8 per cent of the global forest carbon stocks1. The decomposition of deadwood is largely governed by climate2-5 with decomposer groups-such as microorganisms and insects-contributing to variations in the decomposition rates2,6,7. At the global scale, the contribution of insects to the decomposition of deadwood and carbon release remains poorly understood7. Here we present a field experiment of wood decomposition across 55 forest sites and 6 continents. We find that the deadwood decomposition rates increase with temperature, and the strongest temperature effect is found at high precipitation levels. Precipitation affects the decomposition rates negatively at low temperatures and positively at high temperatures. As a net effect-including the direct consumption by insects and indirect effects through interactions with microorganisms-insects accelerate the decomposition in tropical forests (3.9% median mass loss per year). In temperate and boreal forests, we find weak positive and negative effects with a median mass loss of 0.9 per cent and -0.1 per cent per year, respectively. Furthermore, we apply the experimentally derived decomposition function to a global map of deadwood carbon synthesized from empirical and remote-sensing data, obtaining an estimate of 10.9 ± 3.2 petagram of carbon per year released from deadwood globally, with 93 per cent originating from tropical forests. Globally, the net effect of insects may account for 29 per cent of the carbon flux from deadwood, which suggests a functional importance of insects in the decomposition of deadwood and the carbon cycle.  
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  Call Number EcoFoG @ webmaster @ Serial 1046  
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Author Levionnois, Sébastien ; Ziegler, Camille ; Heuret, Patrick ; Jansen, Steven ; Stahl, Clément ; Calvet, Emma ; Goret, Jean-Yves ; Bonal, Damien ; Coste, Sabrina doi  openurl
  Title Is vulnerability segmentation at the leaf‑stem transition a drought resistance mechanism? A theoretical test with a trait‑based model for Neotropical canopy tree species Type Journal Article
  Year 2021 Publication Annals of Forest Science Abbreviated Journal  
  Volume 78 Issue 4 Pages (up) 78-87  
  Keywords Neotropics, bark, canopy, capacitance, drought, drought tolerance, embolism, leaves, models, transpiration, trees, tropical rain forests, xylem  
  Abstract Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stem. However, although it has been intensively investigated these past decades, the extent to which vulnerability segmentation promotes drought resistance is not well understood. Based on a trait-based model, this study theoretically supports that vulnerability segmentation enhances shoot desiccation time across 18 Neotropical tree species. CONTEXT: Leaf-stem vulnerability segmentation predicts lower xylem embolism resistance in leaves than stems thereby preserving expensive organs such as branches or the trunk. Although vulnerability segmentation has been intensively investigated these past decades to test its consistency across species, the extent to which vulnerability segmentation promotes drought resistance is not well understood. AIMS: We investigated the theoretical impact of the degree of vulnerability segmentation on shoot desiccation time estimated with a simple trait-based model. METHODS: We combined data from 18 tropical rainforest canopy tree species on embolism resistance of stem xylem (flow-centrifugation technique) and leaves (optical visualisation method). Measured water loss under minimum leaf and bark conductance, leaf and stem capacitance, and leaf-to-bark area ratio allowed us to calculate a theoretical shoot desiccation time (tcᵣᵢₜ). RESULTS: Large degrees of vulnerability segmentation strongly enhanced the theoretical shoot desiccation time, suggesting vulnerability segmentation to be an efficient drought resistance mechanism for half of the studied species. The difference between leaf and bark area, rather than the minimum leaf and bark conductance, determined the drastic reduction of total transpiration by segmentation during severe drought. CONCLUSION: Our study strongly suggests that vulnerability segmentation is an important drought resistance mechanism that should be better taken into account when investigating plant drought resistance and modelling vegetation. We discuss future directions for improving model assumptions with empirical measures, such as changes in total shoot transpiration after leaf xylem embolism.  
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  Call Number EcoFoG @ webmaster @ Serial 1034  
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Author Tahiri, A.; Amissa Adima, A.; Adjé, F.A.; Amusant, N. url  openurl
  Title Pesticide effects and screening of extracts of Azadirachta Indica (A.) Juss. on the Macrotermes bellicosus rambur termite Type Journal Article
  Year 2011 Publication Bois et Forets des Tropiques Abbreviated Journal Effet pesticide et screening des extraits de Azadirachta indica (A.) Juss. sur le termite Macroterme  
  Volume 65 Issue 310 Pages (up) 79-88  
  Keywords Azadirachta indica; Pesticide properties; Phytochemical screening; Termite  
  Abstract To recommend applications in the field of a naturally insecticide plant substance as an alternative to chemical control against termite attacks, several important prerequisites need to be satisfied to ensure its effectiveness. The toxicity, lethal dose, mode of action, persistence of insecticide effect and chemical composition of total aqueous, alcohol and hexane extracts of the leaves and seeds of the neem tree, Azadirachta indica, were tested with the Macrotermes bellicosus termite. The extracts were found to be highly toxic to termites on contact, killing the entire population tested. The insecticide effect of the extracts persisted from 2.4 to 4.2 days. The aqueous and hexane extracts were the most toxic (LD50 0.422±0.018 to 4,466±0,162 mg/l). Contact and inhalation were both essential to their effectiveness. The aqueous extract of seeds, which is the most active, is also capable of being transferred through the colony during social tasks. However, it seems to have an anti-appetent effect on termites and does not act by ingestion. It contains phenol compounds (tannins and flavonoids) and saponins. The hexane extract of seeds is oily and contains 11 fatty acids as well as terpenoids, flavonoids and saponins.  
  Address Cirad Laboratoire de Chimie du Bois, 34398 Montpellier Cedex 5, France  
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  Notes Export Date: 20 November 2012; Source: Scopus Approved no  
  Call Number EcoFoG @ webmaster @ Serial 447  
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Author Fortunel, C.; Ruelle, J.; Beauchene, J.; Fine, P.V.A.; Baraloto, C. url  openurl
  Title Wood specific gravity and anatomy of branches and roots in 113 Amazonian rainforest tree species across environmental gradients Type Journal Article
  Year 2014 Publication New Phytologist Abbreviated Journal New Phytol.  
  Volume 202 Issue 1 Pages (up) 79-94  
  Keywords Amazonian forests; Branch; Environmental gradients; Neotropical trees; Root; Wood anatomical traits; Wood density; Wood functions  
  Abstract Wood specific gravity (WSG) is a strong predictor of tree performance across environmental gradients. Yet it remains unclear how anatomical elements linked to different wood functions contribute to variation in WSG in branches and roots across tropical forests. We examined WSG and wood anatomy in white sand, clay terra firme and seasonally flooded forests in French Guiana, spanning broad environmental gradients found throughout Amazonia. We measured 15 traits relating to branches and small woody roots in 113 species representing the 15 most abundant species in each habitat and representative species from seven monophyletic lineages occurring in all habitats. Fiber traits appear to be major determinants of WSG, independent of vessel traits, in branches and roots. Fiber traits and branch and root WSG increased from seasonally flooded species to clay terra firme species and lastly to white sand species. Branch and root wood traits were strongly phylogenetically constrained. Lineages differed in wood design, but exhibited similar variation in wood structure across habitats. We conclude that tropical trees can invest differently in support and transport to respond to environmental conditions. Wind disturbance and drought stress represent significant filters driving tree distribution of Amazonian forests; hence we suggest that biophysical explanations should receive more attention. © 2013 New Phytologist Trust.  
  Address Department of Biology, University of Florida, Gainesville, FL, 32611, United States  
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  Notes Export Date: 10 March 2014; Source: Scopus; Coden: Nepha; Language of Original Document: English; Correspondence Address: Fortunel, C.; INRA, UMR Ecologie des Forêts de Guyane, BP 709, Kourou Cedex, 97387, France; email: claire.fortunel@ecofog.gf; Funding Details: DEB-0743103, NSF, National Science Foundation; Funding Details: DEB-0743800, NSF, National Science Foundation Approved no  
  Call Number EcoFoG @ webmaster @ Serial 531  
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Author Laurans, M.; Herault, B.; Vieilledent, G.; Vincent, G. url  openurl
  Title Vertical stratification reduces competition for light in dense tropical forests Type Journal Article
  Year 2014 Publication Forest Ecology and Management Abbreviated Journal For. Ecol. Manage.  
  Volume 329 Issue Pages (up) 79-88  
  Keywords Adult stature; French Guiana; Hierarchical bayesian model; Local crowding; Niche partitioning; Bayesian networks; Growth rate; Adult stature; French Guiana; Hierarchical Bayesian modeling; Local crowding; Niche partitioning; Reforestation  
  Abstract Differential growth response to light level is widely accepted as a potential mechanism for maintaining tree species richness in tropical forests. The position of tree species in the hierarchy of the canopy is considered an important indicator of species light capture and growth strategy. Paradoxically, the relative importance of species identity and competition for light in determining individual tree growth is poorly documented at the adult stage. In this study, we used a hierarchical Bayesian model to quantify the overall importance of species identity, light and belowground competition as determinants of tree growth in French Guiana tropical forest. Light competitive status is assessed by a crown exposure score and below ground competition is estimated from local crowding. We examined species sensitivity to both types of competition in relation to adult stature. Our results are based on annual diameter increments of more than 13,510 stems from 282 species monitored over 10years. Mean annual growth rate was 0.11cmy-1 with species identity explaining 35% of the individual variation in growth rate. Crown exposure and local crowding explained 3.5% and 2.4% of the variation in growth rate, respectively. Predicted changes in growth rate as crown exposure (resp. local crowding) index changed from lower to upper interquartile level was 0.03cmy-1 (resp. 0.02cmy-1). Species sensitivity to crown exposure and to local crowding were positively correlated (i) with predicted growth rate at high-light standardized conditions and (ii) with adult stature.This vertical niche partitioning is invoked to explain the limited contribution made by level of light competition for predicting individual tropical tree growth as the community-level response is dominated by the abundance of small-statured species with low sensitivity to light level.Light appears to drive the stem growth rate of tropical trees through species differentiation more than through individual tree growth limitation. This vertical stratification complements the previously reported regeneration niche and together these provide evidence for light niche partitioning in the three-dimensional space of tropical forests. © 2014 Elsevier B.V.  
  Address IRD, UMR AMAP, TA A-51/PS1, Bd de la Lironde, 34398 Montpellier Cedex 5, France  
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  Publisher Elsevier Place of Publication Editor  
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  ISSN 03781127 (Issn) ISBN Medium  
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  Notes Export Date: 30 July 2014; Coden: Fecmd; Correspondence Address: Laurans, M.; CIRAD, UMR AMAP, TA A-51/PS1, Bd de la Lironde, 34398 Montpellier Cedex 5, France; email: laurans@cirad.fr Approved no  
  Call Number EcoFoG @ webmaster @ Serial 551  
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Author Courtois, E.A.; Baraloto, C.; Timothy Paine, C.E.; Petronelli, P.; Blandinieres, P.-A.; Stien, D.; Houel, E.; Bessiere, J.-M.; Chave, J. doi  openurl
  Title Differences in volatile terpene composition between the bark and leaves of tropical tree species Type Journal Article
  Year 2012 Publication Phytochemistry Abbreviated Journal Phytochemistry  
  Volume 82 Issue Pages (up) 81-88  
  Keywords French Guiana; Herbivory; Optimal defense theory; Secondary metabolites; Wood  
  Abstract Volatile terpenes are among the most diverse class of defensive compounds in plants, and they are implicated in both direct and indirect defense against herbivores. In terpenes, both the quantity and the diversity of compounds appear to increase the efficiency of defense as a diverse blend of compounds provides a more efficient protection against a broader range of herbivores and limits the chances that an enemy evolves resistance. Theory predicts that plant defensive compounds should be allocated differentially among tissues according to the value of the tissue, its cost of construction and the herbivore pressure on it. We collected volatile terpenes from bark and leaves of 178 individual tree belonging to 55 angiosperm species in French Guiana and compare the kind, amount, and diversity of compounds in these tissues. We hypothesized that in woody plants, the outermost part of the trunk should hold a more diverse blend of volatile terpenes. Additionally, as herbivore communities associated with the leaves is different to the one associated with the bark, we also hypothesized that terpene blends should be distinct in the bark vs. the leaves of a given species. We found that the mixture of volatile terpenes released by bark is different and more diverse than that released by leaves, both in monoterpenes and sesquiterpenes. This supports our hypothesis and further suggests that the emission of terpenes by the bark should be more important for trunk defense than previously thought.  
  Address Station d'Écologie Expérimentale du CNRS Moulis, USR 2936, 2 route du CNRS, 09200 Moulis, France  
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  Notes Export Date: 4 September 2012; Source: Scopus; Coden: Pytca; doi: 10.1016/j.phytochem.2012.07.003; Language of Original Document: English; Correspondence Address: Courtois, E.A.; Station d'Écologie Expérimentale du CNRS Moulis, USR 2936, 2 route du CNRS, 09200 Moulis, France; email: courtoiselodie@gmail.com Approved no  
  Call Number EcoFoG @ webmaster @ Serial 425  
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