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Leroy, C.; Sabatier, S.; Wahyuni, N.S.; Barczi, J.F.; Dauzat, J.; Laurans, M.; Auclair, D. |
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Title  |
Virtual trees and light capture: a method for optimizing agroforestry stand design |
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Journal Article |
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Year |
2009 |
Publication |
Agroforestry Systems |
Abbreviated Journal |
Agrofor. Syst. |
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77 |
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1 |
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37-47 |
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Acacia mangium; Tectona grandis; Agroforestry; Light interception; Plant architecture; Simulation; 3D virtual plant |
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In agroforestry systems, the distribution of light transmitted under tree canopies can be a limiting factor for the development of intercrops. The light available for intercrops depends on the quantity of light intercepted by tree canopies and, consequently, on the architecture of the tree species present. The influence of tree architecture on light transmission was analysed using dynamic 3D architectural models. The architectural analysis of Acacia mangium and Tectona grandis was performed in Indonesian agroforestry systems with trees aged from 1 to 3 years. 3D virtual trees were then generated with the AmapSim simulation software and 3D virtual experiments in which tree age, planting density, planting pattern and pruning intensity varied were reconstructed in order to simulate light available for the crop. Canopy closure of trees was more rapid in A. mangium than in T. grandis agroforestry systems; after 3 years the quantity of light available for A. mangium intercrops was three times lower than under T. grandis. Simulations with A. mangium showed that practices such as pruning and widening tree spacing enable to increase the total transmitted light within the stand. On T. grandis, modification of the tree row azimuth resulted in changes in the spatial and seasonal distribution of light available for the intercrops. These results are discussed in terms of agroforestry system management. |
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[Sabatier, Sylvie; Barczi, Jean-Francois; Dauzat, Jean; Laurans, Marilyne] CIRAD, UMR AMAP Botan & Bioinformat Architecture Plantes, F-34398 Montpellier 5, France, Email: sylvie-annabel.sabatier@cirad.fr |
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0167-4366 |
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ISI:000268865600004 |
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EcoFoG @ eric.marcon @ |
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199 |
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Staudt, K.; Serafimovich, A.; Siebicke, L.; Pyles, R.D.; Falge, E. |
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Title |
Vertical structure of evapotranspiration at a forest site (a case study) |
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Journal Article |
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Year |
2011 |
Publication |
Agricultural and Forest Meteorology |
Abbreviated Journal |
Agric. For. Meterol. |
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151 |
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6 |
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709-729 |
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Eddy-covariance; Evapotranspiration; In-canopy profiles; Model; Picea abies L.; Sap flux; coniferous forest; ecosystem modeling; eddy covariance; evapotranspiration; forest canopy; sap flow; Fichtelgebirge; Germany; Picea abies |
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The components of ecosystem evapotranspiration of a Norway spruce forest (Picea abies L.) as well as the vertical structure of canopy evapotranspiration were analyzed with a combination of measurements and models for a case study of 5 days in September 2007. Eddy-covariance and sap flux measurements were performed at several heights within the canopy at the FLUXNET site Waldstein-Weidenbrunnen (DE-Bay) in the Fichtelgebirge mountains in Germany. Within and above canopy fluxes were simulated with two stand-scale models, the 1D multilayer model ACASA that includes a third-order turbulence closure and the 3D model STANDFLUX. The soil and understory evapotranspiration captured with the eddy-covariance system in the trunk space constituted 10% of ecosystem evapotranspiration measured with the eddy-covariance system above the canopy. A comparison of transpiration measured with the sap flux technique and inferred from below and above canopy eddy-covariance systems revealed higher estimates from eddy-covariance measurements than for sap flux measurements. The relative influences of possible sources of this mismatch, such as the assumption of negligible contribution of evaporation from intercepted water, and differences between the eddy-covariance flux footprint and the area used for scaling sap flux measurements, were discussed. Ecosystem evapotranspiration as well as canopy transpiration simulated with the two models captured the dynamics of the measurements well, but slightly underestimated eddy-covariance values. Profile measurements and models also gave us the chance to assess in-canopy profiles of canopy evapotranspiration and the contributions of in-canopy layers. For daytime and a coupled or partly coupled canopy, mean simulated profiles of both models agreed well with eddy-covariance measurements, with a similar performance of the ACASA and the STANDFLUX model. Both models underestimated profiles for nighttime and decoupled conditions. During daytime, the upper half of the canopy contributed approximately 80% to canopy evapotranspiration, whereas during nighttime the contribution shifted to lower parts of the canopy. © 2010 Elsevier B.V. |
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Max Planck Institute for Chemistry, Biogeochemistry Department, Joh.-J.-Becherweg 27, 55128 Mainz, Germany |
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01681923 (Issn) |
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Cited By (since 1996): 3; Export Date: 21 October 2011; Source: Scopus; Coden: Afmee; doi: 10.1016/j.agrformet.2010.10.009; Language of Original Document: English; Correspondence Address: Staudt, K.; University of Bayreuth, Department of Micrometeorology, 95440 Bayreuth, Germany; email: katharina.staudt@uni-bayreuth.de |
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EcoFoG @ webmaster @ |
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349 |
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Laurans, M.; Herault, B.; Vieilledent, G.; Vincent, G. |
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Title |
Vertical stratification reduces competition for light in dense tropical forests |
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Journal Article |
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Year |
2014 |
Publication |
Forest Ecology and Management |
Abbreviated Journal |
For. Ecol. Manage. |
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329 |
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79-88 |
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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 |
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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. |
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IRD, UMR AMAP, TA A-51/PS1, Bd de la Lironde, 34398 Montpellier Cedex 5, France |
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Elsevier |
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03781127 (Issn) |
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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 |
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EcoFoG @ webmaster @ |
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551 |
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Touchard, A.; Labrière, N.; Roux, O.; Petitclerc, F.; Orivel, J.; Escoubas, P.; Koh, J.M.S.; Nicholson, G.M.; Dejean, A. |
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Title |
Venom toxicity and composition in three Pseudomyrmex ant species having different nesting modes |
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Journal Article |
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Year |
2014 |
Publication |
Toxicon |
Abbreviated Journal |
Toxicon |
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88 |
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67-76 |
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Ant venoms; Ants; Arboreal and ground-nesting ants; Evolution; Peptides; Pseudomyrmex; ant venom; acute toxicity; animal experiment; ant; article; biochemical composition; controlled study; disulfide bond; high performance liquid chromatography; lethality; matrix assisted laser desorption ionization time of flight mass spectrometry; molecular weight; myrmecophyte; nesting; nonhuman; predator prey interaction; priority journal; Pseudomyrmex gracilis; Pseudomyrmex penetrator; Pseudomyrmex termitarius; species diversity; toxin analysis |
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We aimed to determine whether the nesting habits of ants have influenced their venom toxicity and composition. We focused on the genus Pseudomyrmex (Pseudomyrmecinae) comprising terrestrial and arboreal species, and, among the latter, plant-ants that are obligate inhabitants of myrmecophytes (i.e., plants sheltering ants in hollow structures). Contrary to our hypothesis, the venom of the ground-dwelling species, Pseudomyrmex termitarius, was as efficacious in paralyzing prey as the venoms of the arboreal and the plant-ant species, Pseudomyrmexpenetrator and Pseudomyrmexgracilis. The lethal potency of P. termitarius venom was equipotent with that of P. gracilis whereas the venom of P. penetrator was less potent. The MALDI-TOF MS analysis of each HPLC fraction of the venoms showed that P. termitarius venom is composed of 87 linear peptides, while both P. gracilis and P. penetrator venoms (23 and 26 peptides, respectively) possess peptides with disulfide bonds. Furthermore, P. penetrator venom contains three hetero- and homodimeric peptides consisting of two short peptidic chains linked together by two interchain disulfide bonds. The large number of peptides in P. termitarius venom is likely related to the large diversity of potential prey plus the antibacterial peptides required for nesting in the ground. Whereas predation involves only the prey and predator, P. penetrator venom has evolved in an environment where trees, defoliating insects, browsing mammals and ants live in equilibrium, likely explaining the diversity of the peptide structures. © 2014 Elsevier Ltd. All rights reserved. |
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Laboratoire Écologie Fonctionnelle et Environnement, 118 Route de Narbonne, 31062 Toulouse, France |
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Elsevier Ltd |
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18793150 (Issn) |
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Export Date: 30 July 2014; Coden: Toxia; Correspondence Address: Labrière, N.; CNRS, UMR Ecologie des Forêts de Guyane (EcoFoG), Campus Agronomique, BP 316, 97379 Kourou cedex, France |
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EcoFoG @ webmaster @ |
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553 |
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Touchard, A.; Aili, S.R.; Téné, N.; Barassé, V.; Klopp, C.; Dejean, A.; Kini, R.M.; Mrinalini; Coquet, L.; Jouenne, T.; Lefranc, B.; Leprince, J.; Escoubas, P.; Nicholson, G.M.; Treilhou, M.; Bonnafé, E. |
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Venom Peptide Repertoire of the European Myrmicine Ant Manica rubida: Identification of Insecticidal Toxins |
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Journal Article |
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2020 |
Publication |
Journal of proteome research |
Abbreviated Journal |
J. Proteome Res. |
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19 |
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4 |
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1800-1811 |
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glycosylated toxin; peptidome; polycationic α-helix; predation; pyroglutamate; reversible neurotoxicity |
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Using an integrated transcriptomic and proteomic approach, we characterized the venom peptidome of the European red ant, Manica rubida. We identified 13 “myrmicitoxins” that share sequence similarities with previously identified ant venom peptides, one of them being identified as an EGF-like toxin likely resulting from a threonine residue modified by O-fucosylation. Furthermore, we conducted insecticidal assays of reversed-phase HPLC venom fractions on the blowfly Lucilia caesar, permitting us to identify six myrmicitoxins (i.e., U3-, U10-, U13-, U20-MYRTX-Mri1a, U10-MYRTX-Mri1b, and U10-MYRTX-Mri1c) with an insecticidal activity. Chemically synthesized U10-MYRTX-Mri1a, -Mri1b, -Mri1c, and U20-MYRTX-Mri1a irreversibly paralyzed blowflies at the highest doses tested (30-125 nmol·g-1). U13-MYRTX-Mri1a, the most potent neurotoxic peptide at 1 h, had reversible effects after 24 h (150 nmol·g-1). Finally, U3-MYRTX-Mri1a has no insecticidal activity, even at up to 55 nmol·g-1. Thus, M. rubida employs a paralytic venom rich in linear insecticidal peptides, which likely act by disrupting cell membranes. |
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VenomeTech, 473 Route des Dolines – Villa 3, Valbonne, 06560, France |
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NLM (Medline) |
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15353907 (Issn) |
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Export Date: 20 April 2020 |
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EcoFoG @ webmaster @ |
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927 |
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Ruelle, J.; Beauchene, J.; Yamamoto, H.; Thibaut, B. |
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Variations in physical and mechanical properties between tension and opposite wood from three tropical rainforest species |
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Journal Article |
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Year |
2011 |
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Wood Science and Technology |
Abbreviated Journal |
Wood Sci. Technol. |
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45 |
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2 |
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339-357 |
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Growth strains were measured in situ in nine trees of three species from a French Guiana tropical rainforest in a clearly active verticality restoration process. The aim was to detect tension wood within the samples. Wood specimens were cut in the vicinity of the growth strain measurements in order to determine the microfibril angle and some mechanical and physical properties. As suspected, tensile growth strain was much higher in tension wood zones, as shown by the slightly higher longitudinal modulus of elasticity. Conversely, tension wood showed reduced compression strength. Longitudinal shrinkage was much higher in tension wood than in opposite wood. Clear relationships between the microfibril angle and longitudinal properties were noted in comparison (i) with those observed in gymnosperm compression wood and (ii) with expected relationships from the organization of wood fibres cell wall structure. |
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[Ruelle, Julien; Yamamoto, Hiroyuki] Nagoya Univ, Grad Sch Bioagr Sci, Nagoya, Aichi 4648601, Japan, Email: julien.ruelle@ecofog.gf |
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Springer |
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0043-7719 |
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ISI:000289477300013 |
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EcoFoG @ webmaster @ |
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305 |
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Quesada, C.A.; Lloyd, J.; Schwarz, M.; Patino, S.; Baker, T.R.; Czimczik, C.; Fyllas, N.M.; Martinelli, L.; Nardoto, G.B.; Schmerler, J.; Santos, A.J.B.; Hodnett, M.G.; Herrera, R.; Luizao, F.J.; Arneth, A.; Lloyd, G.; Dezzeo, N.; Hilke, I.; Kuhlmann, I.; Raessler, M.; Brand, W.A.; Geilmann, H.; Moraes, J.O.; Carvalho, F.P.; Araujo, R.N.; Chaves, J.E.; Cruz, O.F.; Pimentel, T.P.; Paiva, R. |
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Variations in chemical and physical properties of Amazon forest soils in relation to their genesis |
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Journal Article |
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2010 |
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Biogeosciences |
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Biogeosciences |
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7 |
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5 |
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1515-1541 |
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Soil samples were collected in six South American countries in a total of 71 different 1 ha forest plots across the Amazon Basin as part of the RAINFOR project. They were analysed for total and exchangeable cations, C, N, pH with various P fractions also determined. Physical properties were also examined and an index of soil physical quality proposed. A diverse range of soils was found. For the western areas near the Andean cordillera and the southern and northern fringes, soils tend to be distributed among the lower pedogenetic levels, while the central and eastern areas of Amazonia have more intensely weathered soils. This gives rise to a large variation of soil chemical and physical properties across the Basin, with soil properties varying predictably along a gradient of pedogenic development. Nutrient pools generally increased slightly in concentration from the youngest to the intermediate aged soils after which a gradual decline was observed with the lowest values found in the most weathered soils. Soil physical properties were strongly correlated with soil fertility, with favourable physical properties occurring in highly weathered and nutrient depleted soils and with the least weathered, more fertile soils having higher incidence of limiting physical properties. Soil phosphorus concentrations varied markedly in accordance with weathering extent and appear to exert an important influence on the nitrogen cycle of Amazon forest soils. |
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[Quesada, C. A.; Lloyd, J.; Baker, T. R.; Fyllas, N. M.] Univ Leeds, Sch Geog, Earth & Biosphere Inst, Leeds LS2 9JT, W Yorkshire, England, Email: betoquesada@yahoo.com.br |
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COPERNICUS GESELLSCHAFT MBH |
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1726-4170 |
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ISI:000278184500011 |
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EcoFoG @ eric.marcon @ |
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58 |
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Bosc, A.; De Grandcourt, A.; Loustau, D. |
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Variability of stem and branch maintenance respiration in a Pinus pinaster tree |
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Journal Article |
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2003 |
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Tree Physiology |
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Tree Physiol. |
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23 |
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4 |
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227-236 |
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model; nitrogen; phloem; sapwood; temperature |
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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. |
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INRA, F-33612 Cestas, France, Email: alexandre.bosc@pierroton.inra.fr |
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HERON PUBLISHING |
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0829-318X |
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ISI:000181841200002 |
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EcoFoG @ eric.marcon @ |
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246 |
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Picard, N.; Gourlet-Fleury, S.; Sist, P. |
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Using process-dependent groups of species to model the dynamics of a tropical rainforest |
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Journal Article |
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2003 |
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Modelling Forest Systems |
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237-248 |
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The high tree species diversity in tropical forests is difficult to take into account in models. The usual solution consists of defining groups of species and then adjusting a set of parameters for each group. In this study, we address this issue by allowing a species to move from one species group to another, depending on the biological process that is concerned. We developed this approach with a matrix model of forest dynamics, for a tropical rainforest in French Guiana, at Paracou, focusing on the methodological aspects. The forest dynamics is split into three components: recruitment, growth and mortality. We then built five recruitment groups, five growth groups and five mortality groups. One species is characterized by a combination of the three groups, thus yielding in total 5 X 5 X 5 = 125 possibilities, out of which 43 are actually observed. The resulting matrix model provides a better view of the floristic composition of the forest, and does not have more parameters than it would have with five global species groups. However, its predictions are no more precise than those of the matrix model based on five global groups. |
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Cirad Foret, Montpellier, France |
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CABI PUBLISHING |
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ISI:000231866400021 |
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EcoFoG @ eric.marcon @ |
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249 |
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Gourlet-Fleury, S.; Comu, G.; Jesel, S.; Dessard, H.; Jourget, J.G.; Blanc, L.; Picard, N. |
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Using models to predict recovery and assess tree species vulnerability in logged tropical forests: A case study from French Guiana |
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2005 |
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Forest Ecology and Management |
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For. Ecol. Manage. |
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209 |
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1-2 |
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69-86 |
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matrix model; individual-based spatially explicit model; regeneration; recruitment; long-term population dynamics |
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A major challenge for forest managers is to define the optimal cutting cycle to ensure that the resource is sustained in the long term. Matrix models of forest dynamics allow time-projection of diameter-class distributions and thus assessment of the time needed, after logging, to recover a given part of the exploitable stock. They are easy to build and they only require, as input variables, the diameter structure of the population(s) under scope. However, such models are based on a coarse description of tree population dynamics and must be used with caution. In particular, as trees are only described from a diameter threshold (usually 10 cm dbh), recruitment of a new tree cannot be linked with the preceding generation since too much time elapsed between seed dispersal and the installation of a 10-cm recruit. This causes predictions of matrix models to be highly questionable in the long term when ingrowth to larger dbh classes greatly depends on the way recruitment has been modelled. We used a case study from French Guiana to test whether or not a simple matrix model is reliable enough to help forest managers choose between management alternatives. We focused on the major timber species Dicorynia guianensis Amshoff (Caesalpiniaceae) harvested under a selective cutting regime. We compared predictions of D. guianensis stock recovery in the short and long term provided by two models: StoMat, a non-regulated matrix model, and SELVA, a single-tree distance dependent model explicitly simulating the entire species life cycle. Both models were independently calibrated on data from Paracou permanent sample plots. We showed that: (i) the short-term recovery of the exploitable stock predicted by StoMat is reliable for a large range of disturbance conditions; (ii) recruitment implementation in StoMat does not influence projections until the third felling cycle; (iii) for shared initial stand conditions SELVA and StoMat give consistent mid- and long-term predictions: the simple recruitment model used into StoMat could efficiently summarise the regeneration processes of the species under low felling intensity. Our results indicate that the current felling regime used in French Guiana may not be sustainable on a long-term basis. In any case, no more than 60% of the initial stock would be recovered after logging. We conclude that simple models can provide as reliable predictions as more complicated ones. They may be sufficient to assess the recovery of a species' exploitable stock even in the long term, or at least assess the (un)sustainability of particular harvesting regimes. (c) 2005 Elsevier B.V. All rights reserved. |
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CIRAD, Dept Forets, F-34398 Montpellier 5, France, Email: sylvie.gourlet-fleury@cirad.fr |
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ELSEVIER SCIENCE BV |
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0378-1127 |
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ISI:000228504600007 |
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EcoFoG @ eric.marcon @ |
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257 |
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