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Diameter and death of whorl and interwhorl branches in Atlas cedar (Cedrus atlantica Manetti): a model accounting for acrotony / François Courbet in Annals of Forest Science, Vol 69 n° 2 (March 2012)  

Public [article]  inAnnals of Forest Science > Vol 69 n° 2 (March 2012) . - pp 125 - 138 Titre : Diameter and death of whorl and interwhorl branches in Atlas cedar (Cedrus atlantica Manetti): a model accounting for acrotony Type de document : Article/Communication Auteurs : François Courbet, Auteur ; Jean-Christophe Hervé (1961-2017) , Auteur ; Etienne K. Klein, Auteur ; Francis Colin, Auteur Année de publication : 2012 Article en page(s) : pp 125 - 138 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Végétation [Termes IGN] branche (arbre) [Termes IGN] Cedrus atlantica [Termes IGN] diamètre des arbres [Termes IGN] houppier [Termes IGN] modèle non linéaire [Termes IGN] modèle numérique [Termes IGN] nutrition végétale Résumé : (auteur) Branch size and branch status (dead or alive) are important characteristics closely related to tree growth and wood quality. The aim of this study was to design models for the diameter and status of branches in Atlas cedar (Cedrus atlantica Manetti). The models were developed from data collected on a set of 32 trees with a wide range of heights (from 3 to 36 m), girths (from 13 to 226 cm), and ages (from 20 to 95 years). A single general segmented model was designed for both whorl and interwhorl branch diameter, taking into account the tree and annual growth unit random effects. The model’s “potential x reducer” form describes the maximum branch diameter profile along the tree and the acrotonic gradient observed in annual shoots. The diameter and status of every branch were modeled based on the vertical position on the trunk and on the height of the base of the living crown. The tree diameter and the branch diameter were used as additional explanatory variables in the branch diameter model and the branch status model, respectively. The model structure is sufficiently general to be suited after re-parameterization for many coniferous species with interwhorl branches such as Spruces, Firs, and Larches. Numéro de notice : A2012-718 Affiliation des auteurs : IFN+Ext (1958-2011) Thématique : FORET Nature : Article DOI : 10.1007/s13595-011-0156-1 Date de publication en ligne : 06/12/2011 En ligne : http://dx.doi.org/10.1007/s13595-011-0156-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=83725 [article]

Significant differences and curvilinearity in the self-thinning relationships of 11 temperate tree species assessed from forest inventory data / Marie Charru in Annals of Forest Science, Vol 69 n° 2 (March 2012)  

Public [article]  inAnnals of Forest Science > Vol 69 n° 2 (March 2012) . - pp 195 - 205 Titre : Significant differences and curvilinearity in the self-thinning relationships of 11 temperate tree species assessed from forest inventory data Type de document : Article/Communication Auteurs : Marie Charru, Auteur ; Ingrid Seynave, Auteur ; François Morneau , Auteur ; Michaël Rivoire, Auteur ; Jean-Daniel Bontemps , Auteur Année de publication : 2012 Article en page(s) : pp 195 - 205 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Termes IGN] auto-éclaircie [Termes IGN] forêt équienne [Termes IGN] forêt tempérée [Termes IGN] inventaire forestier national (données France) [Termes IGN] modèle statistique [Termes IGN] peuplement pur [Vedettes matières IGN] Inventaire forestier Résumé : (auteur) Introduction : In pure and even-aged stands, the allometry between mean tree size and maximum stand density—or self-thinning relationship—has long been considered a constant among tree species. Although the self-thinning allometric coefficient has been shown to be species-dependent, estimates available for a given species also differ. Whether this coefficient truly varies across species thus remains an open issue. A potential cause of variation in the coefficient may lie in a departure from the allometric assumption in the self-thinning relationship. Methods : We analysed the species dependence of the self-thinning relationship for 11 temperate and Mediterranean tree species growing in pure and even-aged stands in France based on the French National Forest Inventory (NFI) data. Self-thinning relationships were fitted using a ‘stochastic frontier’ technique. Pairwise comparison tests of the self-thinning allometric coefficients were implemented. We also investigated the allometric nature of the relationship by testing a linear and a curvilinear model of log density against the log quadratic mean diameter. Results : Self-thinning relationships were clearly evidenced from the NFI data and displayed significant differences between species. The curvilinear model was significantly more accurate for 7 out of 11 species and depicted a concave relationship, suggesting a decrease in self-tolerance over ontogeny. Conclusion : As a major finding, the self-thinning relationship significantly varies across species. We emphasise the need to consider a high number of species to show such specific variations in the self-thinning relationship. Another important outcome is that the self-tolerance depends on the developmental stage. Numéro de notice : A2012-758 Affiliation des auteurs : IFN+Ext (1958-2011) Thématique : FORET Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1007/s13595-011-0149-0 Date de publication en ligne : 11/11/2011 En ligne : https://doi.org/10.1007/s13595-011-0149-0 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=98388 [article]