Quantitative Ecological Inventory of Terra Firme and Varzea Tropical Forest on the Rio Xingu, Brazilian Amazon

Abstract

Three hectares of Amazonian terra firme forest and an adjacent one-half hectare of varzea forest were quantitatively inventoried at O Deserto, on the Rio Xingu, Para, Brazil. In the terra firme forest, 1420 individual trees greater than ten cm dbh, in 39 families and 265 species, were inventoried. In the varzea forest, there were 220 individual trees, in 17 families and 40 species.Cenostigma macrophyllum andOrbignya sp. were the most important species in the terra firme forest;Mollia lepidota andLeonia glycycarpa were most important in the varzea forest. Among one-hectare subplots of the total three-hectare terra firme sample, the number of trees ranged from 393 to 460, the number of families was a constant 33, and the number of species ranged from 118 to 162. This variation indicates that one-hectare samples are too small to be used to estimate the species richness of the total forest. The terra firme forest was richer in species and had a greater stature than the varzea forest.