Read J. auteur aut IRD Hope G.S. auteur aut IRD Gaudrie E. auteur aut IRD Jaffré Tanguy auteur aut IRD Veillon Jean-Marie auteur aut IRD text conferencePaper eng text/pdf reformatted digital access Permanent plots are being established in monodominant and mixed rainforests over a range of altitudes on ultramafic soils in New Caledonia to investigate the factors determining canopy richness. Initial studies are examining the dynamics of the major tree species to assess the role of disturbance and successional change in controlling the canopy richness of these stands. The monodominant stands being investigated are dominated by Nothofagus spp. and have a high species richness in the understorey, despite the low richness of the upper canopy. Many of the species recorded in the understorey, are potentially capable of reaching the canopy, including species that typically occur in the canopy of nearby mixed rainforests. However, the dominant canopy species of Nothofagus are rare as saplings, with the population sample showing a bell-shaped size distribution. It therefore appears that these Nothofagus-dominated forests are successional, and in the hypothetical absence of disturbance, the Nothofagus-dominated canopy is likely to be replaced by a species rich canopy similar in composition to the adjacent mixed rainforests. Study of adjacent mixed rainforests suggests that these are seral forests, with many of the common canopy species not represented in the understorey. Some of the canopy species are well represented in the smaller size classes, and there are few canopy species occurring in the understorey which are not also represented in the canopy. Therefore, these forests may eventually become less species-rich as the forest ages, with only the most shade-tolerant species occuring in the canopy. (Résumé d'auteur) specialized FORET DENSE ROCHE ULTRABASIQUE CANOPEE DYNAMIQUE DE POPULATION STRUCTURE DU PEUPLEMENT NOUVELLE CALEDONIE 082VEGET02 Ecologie des Milieux Serpentiniques : Conférence Internationale = Serpentine Ecology : International Conference, 2., Nouméa (NCL), 1995/07/31; 1995/08/05 39 Nouméa ORSTOM 1995 https://www.documentation.ird.fr/hor/fdi:010005650 [F A010005638] https://www.documentation.ird.fr/hor/fdi:010005650 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers10-09/010005650.pdf IRD - Base Horizon / Pleins textes 1996-06-12 2010-10-18 fdi:010005650 fre