Estructura y composición florística del bosque de la llanura aluvial en la Amazonía peruana: I. El bosque alto

Three peruvian flood plain forests adjacent to the Ucayali river were sampled using nine one hectare permanent sample plots in which stems exceeding 10 cm DBH were identified and measured. These plots have been measured 4 times during 1993- 1997, and provide the basis for the results reported here. Three plots were established in each of the three forest types high restinga, low restinga, and tahuampa, characterized in part by and annual inundation of 1, 2 and 4 months per year, respectively. Stem density varies from 446 to 601 per ha, and the basal area ranges between 20-29 m2/ha. A total of 321 species were recorded in the nine hectare sample, with 88-141 species in each one hectare plot. Species composition indicated a relatively low similarity between the forest types. Plots with the longest flooding contained the most species, expressed both as per unit area as well as per 1 000 stems. The flood plain forests contain fewer tree species than the non-flooded terra firme forest. In all three forests Legminosae, Euphorbiaceae, Annonaceae and Lauraceae, are important. The Moraceae family is conspicuous in both high restinga, as is Rubiaceae in low restinga. Lecythidaceae, Sapotaceae, and Chrysobalanaceae exhibit relatively high values in the tahuampa forest. High species importance values are obtained for Maquira coriacea, Guarea macrophylla, Terminalia oblonga, Spondias mombin, Ceiba pentandra, Hura crepitans, Schweilera spp., Campsiandra angustifolia, Pouteria spp., Licania micrantha, Parinari excelsa, and Calycophyllum spruceanum. Among the species of smaller stature, Drypetes amazonica, Leonia glycicarpa, Theobroma cacao, and Protium nodulosum attain high values.