A comparison of two "terra firme" amazonian forests shows different patterns of spatial organization. In one case multistorey canopy appears to be correlated with a coarse grained mosaic of clearings and with an important lateral heterogeneity in the forest. On the other hand, a fine grained mosaic of clearings and relative homogeneity of the forest seems associated to a closely-packed uniform canopy. These different patterns of spatial organization affect settling and growth conditions of the different species according to their specific light demands. This leads to the question whether the structural organization of the forest does or does not play a role in the distribution of the species as suggested by the case of acaulescent palm-trees in Central Amazonian forests. (Résumé d'auteur
