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Is the variability of key wood properties linked with the variability of key architectural traits? Case of planted Teak in Togo regarding thinning and provenance / Kodjo Tondjo in Annals of Forest Science, vol 72 n° 6 (September 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 6 (September 2015) . - pp 717 - 729 Titre : Is the variability of key wood properties linked with the variability of key architectural traits? Case of planted Teak in Togo regarding thinning and provenance Type de document : Article/Communication Auteurs : Kodjo Tondjo, Auteur ; Loïc Brancheriau, Auteur ; Sylvie-Annabel Sabatier, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 717 - 729 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] analyse diachronique [Termes IGN] Congo [Termes IGN] croissance des arbres [Termes IGN] image proche infrarouge [Termes IGN] Tectona grandis [Termes IGN] Togo Résumé : (auteur) Key message : A retrospective architectural analysis performed on planted teaks in Togo showed that the variation of wood radial properties were linked with tree ontogeny, and that these relationships depended on thinning practices and provenance. Context : Variability in growth, flowering and forking in individual trees according to origin and/or thinning practices may affect wood structure and consequently impact wood physical properties. We tested this hypothesis in teak. Aims : We sought evidence of: (1) origin effects (Togolese versus Tanzanian teak) on growth, flowering, cambial growth and wood properties; (2) thinning effects on these variables and (3) relationships between tree ontogeny and radial variations of wood properties. Methods : A retrospective architectural analysis was used to draw stem growth and near infrared spectroscopy to assess radial variations of wood properties. Results : Flowering reflects tree vigour and began at an earlier age in Togolese than in Tanzanian provenances. No differences were detected in regards to growth ring surface area, basic density and modulus of elasticity. Both systematic and selective thinnings improved growth without impacting the two latter properties. Stabilization of the growth ring area observed at 4 years old was associated with a decline in stem annual extension with a 1-year time lag. Conclusions : Architectural analyses showed that radial growth was linked with tree ontogeny. This method can be extended to subsequent developmental stages, i.e. to older trees with economic interest, and used to determine architectural traits that are useful in tree selection. Numéro de notice : A2015-408 Affiliation des auteurs : non IGN Thématique : FORET Nature : Article DOI : 10.1007/s13595-014-0425-x Date de publication en ligne : 24/10/2014 En ligne : https://doi.org/10.1007/s13595-014-0425-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76895 [article]

A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L / Herizo Rakotovololonalimanana in Annals of Forest Science, vol 72 n° 6 (September 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 6 (September 2015) . - pp 753 - 761 Titre : A novel method to correct for wood MOE ultrasonics and NIRS measurements on increment cores in Liquidambar styraciflua L Type de document : Article/Communication Auteurs : Herizo Rakotovololonalimanana, Auteur ; Gilles Chaix, Auteur ; Loïc Brancheriau, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 753 - 761 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse comparative [Termes IGN] élasticité [Termes IGN] image proche infrarouge [Termes IGN] Liquidambar styraciflua [Termes IGN] spectrométrie [Termes IGN] télédétection acoustique [Termes IGN] ultrason Résumé : (auteur) Key message : Ultrasounds overestimate the MOE value. This paper analyses the causes of this difference and opens the perspective for a novel method allowing the calculation of the correct MOE from ultrasounds or NIRS measurements on cores. Context : Standardized methods for determining wood modulus of elasticity (MOE) are destructive and require many replicates. Other methods such as NIRS and ultrasound have been developed to characterize wood properties and overcome these constraints. Aim : The aim of this study was to compare the two MOE measurement methods (NIRS and ultrasound) applied to cores of wood taken from standing trees (Liquidambar styraciflua). Methods : MOE, measured by an acoustic method in standard samples (360 × 20 × 20 mm), was used as a reference. Then MOE was predicted by an NIRS model and determined using ultrasound in standard samples (360 × 20 × 20 mm), small samples (10 × 20 × 20 mm), and cores (15 mm in diameter). Result : MOE values determined by acoustic method on standard samples and by ultrasonic method on small samples were correlated (R 2 = 0.72) and were not statistically different. The NIRS PLS regression yielded a model with R 2 cv = 0.80. The link between NIRS and ultrasound on cores was statistically significant (R 2 = 0.68). Conclusion : The ultrasonic technique determines an apparent modulus enables comparative data analysis. This apparent modulus can be used for quantitative analysis if a corrective model is used. A correction formula to ultrasonic MOE was proposed in the case of a prismatic geometry. Numéro de notice : A2015-409 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.1007/s13595-015-0469-6 Date de publication en ligne : 12/03/2015 En ligne : https://doi.org/10.1007/s13595-015-0469-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76896 [article]

Recommendations for the use of tree models to estimate national forest biomass and assess their uncertainty / Matieu Henry in Annals of Forest Science, vol 72 n° 6 (September 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 6 (September 2015) . - pp 769 - 777 Titre : Recommendations for the use of tree models to estimate national forest biomass and assess their uncertainty Type de document : Article/Communication Auteurs : Matieu Henry, Auteur ; Miguel Cifuentes Jara, Auteur ; Maxime Réjou-Méchain, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 769 - 777 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Statistiques [Termes IGN] arbre (flore) [Termes IGN] biomasse [Termes IGN] disponibilité des données [Termes IGN] estimation statistique [Termes IGN] incertitude des données [Termes IGN] inventaire forestier (techniques et méthodes) [Termes IGN] inventaire forestier national (données France) [Termes IGN] masse végétale [Termes IGN] sylviculture [Termes IGN] volume (grandeur) Résumé : (auteur) Key message : Three options are proposed to improve the accuracy of national forest biomass estimates and decrease the uncertainty related to tree model selection depending on available data and national contexts. Introduction : Different tree volume and biomass equations result in different estimates. At national scale, differences of estimates can be important while they constitute the basis to guide policies and measures, particularly in the context of climate change mitigation. Method : Few countries have developed national tree volume and biomass equation databases and have explored its potential to decrease uncertainty of volume and biomasttags estimates. With the launch of the GlobAllomeTree webplatform, most countries in the world could have access to country-specific databases. The aim of this article is to recommend approaches for assessing tree and forest volume and biomass at national level with the lowest uncertainty. The article highlights the crucial need to link allometric equation development with national forest inventory planning efforts. Results : Models must represent the tree population considered. Data availability; technical, financial, and human capacities; and biophysical context, among other factors, will influence the calculation process. Conclusion : Three options are proposed to improve accuracy of national forest assessment depending on identified contexts. Further improvements could be obtained through improved forest stratification and additional non-destructive field campaigns. Numéro de notice : A2015-410 Affiliation des auteurs : non IGN Thématique : FORET/MATHEMATIQUE Nature : Article DOI : 10.1007/s13595-015-0465-x Date de publication en ligne : 20/03/2015 En ligne : https://doi.org/10.1007/s13595-015-0465-x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76898 [article]

An overview of existing and promising technologies for national forest monitoring / Matieu Henry in Annals of Forest Science, vol 72 n° 6 (September 2015)  

Public [article]  inAnnals of Forest Science > vol 72 n° 6 (September 2015) . - pp 779 - 788 Titre : An overview of existing and promising technologies for national forest monitoring Type de document : Article/Communication Auteurs : Matieu Henry, Auteur ; Maxime Réjou-Méchain, Auteur ; Miguel Cifuentes Jara, Auteur ; et al., Auteur Année de publication : 2015 Article en page(s) : pp 779 - 788 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] évolution technologique [Termes IGN] surveillance forestière [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) [introduction] [...] During the last decades, the amount of information collected during forest inventories has thus grown rapidly and has, in turn, improved our ability to survey and manage many services such as biodiversity, carbon sequestration, or recreation. However, national forest monitoring approaches remain very heterogeneous from one country to another, and many national systems have still not taken the full advantage of newly operational technologies, despite an increasing availability of free, or at least less costly, data. This is probably because the use of these technologies to assess forest structural properties is, for the most part, used by only a few specialists and is largely confined to the research sector. The objective of this paper is to raise awareness by presenting, in a comprehensible way, some existing and promising technologies for supporting national forest monitoring. Numéro de notice : A2015-411 Affiliation des auteurs : non IGN Thématique : FORET/SOCIETE NUMERIQUE Nature : Article DOI : 10.1007/s13595-015-0463-z Date de publication en ligne : 20/03/2015 En ligne : https://doi.org/10.1007/s13595-015-0463-z Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76899 [article]