The objective of this study was to group the Work Units (UT) of the Annual Production Unit (UPA) into homogeneous classes of volumetric stock and to analyze the floristic composition, the diversity and the horizontal and diametric structures, by stock class. Data came from a full survey or census, with the mapping of precommercial and potentially commercial trees. These data were provided, through agreement, by Orsa Florestal. The studied area is located in the municipality of Almeirim, State of Para, Brazil. In the census, 469 UTs (250 x 400 m), totalizing 4,690 ha and 191,640 trees with DAP > 35.0 cm were evaluated. The cluster (Ward method) and discriminant (Fisher method) analyses were used and three stock classes, or productivity classes, were obtained. The richness and diversity of the arboreous species with DAP > 35.0 cm of the UPA were 540 species and 4.52 nats.individual-1, respectively. These figures are very high but realistic because they were obtained from a census. The cutting intensity can be determined by the productive capacity of each UT and thus result in a harvest with minimum environmental impact, when compared to the maximum cutting intensity of 30 m³.ha-1 with an initial cutting cycle of 35 years for a sustainable forest management plan. The permanent plots could also be distributed by productivity classes, reducing cost and increasing the growth estimate accuracies of the managed forest.
Forest Management; Natural Forest; Stock Class
