Imprecision in Yield Estimates Using Timber Volume in Forest Management Plans in the Amazon

The yield of logging in a forest management area using only the volume variable is not sufficient to assess effective wood productivity. The objective was to evaluate production using different logging variables to point out possible divergences between what was planned and what was actually carried out, in order to indicate adjustments to annual operating plans (AOPs) in the Amazon. The database comes from a community forest management area in the Tapajós National Forest, con-sidering three sources: 100% inventory, AOP planning and the post-exploration report. The pro-duction yield considering the number of trees felled and the effective volume were compared with the AOP planning. The volume estimated by the generic equation was compared with the cubed volume and the commercial height variable was evaluated. Of the 6,267 trees selected, 5,090 trees were harvested (3.2 trees.ha-1), indicating a yield of 85.0% of the estimated volume. Of the 25 commercial species logged, the most representative were: Manilkara huberi, Vochysia maxima, Lec-ythis lurida, Couratari guianensis and Hymenaea courbaril. It can be concluded that the number of trees, cubed volume and commercial height are post-exploration yield response variables and not just volume, as is currently used in SFMPs.