Population dynamics of canopy trees in New Caledonian rain forests : are monodominant Nothofagus (Nothofagaceae) forests successional to mixed rain forests ? Read, J. /Jaffré, Tanguy FORET SECONDAIRE ARBRE FORESTIER CANOPEE FORESTIERE DOMINANCE DYNAMIQUE DE POPULATION STRUCTURE DE POPULATION REGENERATION DENSITE DE POPULATION EVOLUTION CYCLONE TROPICAL ALTITUDE TAILLE FEU ANALYSE DE COHORTES In New Caledonia, rain forests with an upper canopy dominated by single species of Nothofagus occur next to mixed-canopy forests, without discernible environmental cause. A potential explanation is that they are different successional stages. To test this hypothesis and predict long-term change in canopy dominance, population size structures of 61 canopy species were analysed in six Nothofagus-dominated forests and three adjacent mixed rain forests. Weibull analysis suggests that these Nothofagus forests are secondary forests, with recruitment insufficient to maintain monodominance, except at a high-altitude site. At low- to mid-altitudes the Nothofagus canopy is predicted to develop into amixed canopy, unlessmoderate to severe disturbance occurs within its reproductive lifespan. However, adjacent mixed rain forests are also secondary, with 85% of analysed species showing no evidence of continuous regeneration. Fifteen species from both forest types showed reverse-J curves suggesting continuous regeneration, but only Calophyllum caledonicum did so consistently. Since few canopy species showed evidence of high shade tolerance and persistence, a small number of shade-tolerant species is predicted to dominate both forests in the long term, in the hypothetical absence of disturbance. Hence, temporal factors associated with disturbances play a key role in determining dominance in these forests. 2013 text https://www.documentation.ird.fr/hor/fdi:010060215 fdi:010060215 Read J., Jaffré Tanguy. Population dynamics of canopy trees in New Caledonian rain forests : are monodominant Nothofagus (Nothofagaceae) forests successional to mixed rain forests ?. 2013, 29 (5), 485-499 EN NOUVELLE CALEDONIE ZONE TROPICALE HUMIDE