Vouacapoua americana Aublet was classified as endangered in 2013 and its extraction banned in 2014. Forest management allows conservation and sustainable production, but, for this, knowledge of diameter distribution is fundamental. This study aimed to characterize and analyze diameter distribution patterns of the species at different sites in the Brazilian Amazon. Data on trees with diameter ≥ 10 cm were acquired from continuous forest in permanent sample plots and preharvest forest inventories (PHFIs) of nine forest management areas. Absolute density, diameter distribution, and De Liocourt quotient (q) were calculated. Diameter distributions were fitted by a linearized Meyer type I distribution function, and the similarity between distributions was analyzed by the nonparametric Kruskal-Wallis test (H-test). The species showed high density (6.31 to 25.55 trees/ha). Mensrured diameters ranged from 10.00 to 127.32 cm. A decreasing behavior was observed in all diameter distributions, with few discontinuous distributions and mostly truncated distributions. The De Liocourt quotient (q) did not show constancy or proximity, with values ranging from 0.4 to 23.48. Diameter distributions did not differ by the Kruskal-Wallis test (H = 15.45, p = 0.3479). Diameter distributions fitted by the Meyer model resulted in an inverted “J”-like curve. The diameter structure showed a high density of individuals, a decreasing distribution from smaller to larger diameter classes, a characteristic inverted “J” pattern, and unbalanced diameter distributions.

There is a lack of understanding on the relationship between the authorized volume of wood harvest in Sustainable Forest Management Plans (SFMP) in the Amazon, the volumes listed in the official systems of volume control, the actual harvested volumes, and the consequences these parameters have for the illegal wood market.The objective of this study was to evaluate the production and volume yield and the number of harvested trees as part of forest management plans in public and private forests through analysis of harvest data from 85 SFMP registered in the official electronic system of control of forest products in the state of Pará. The forest management plans were categorized into public (federal and state), and private, with these being further subdivided into having one or more than one annual production unit, and community-managed forest. This analysis was based on the hypothesis that production and volume yield from SFMP in public and private forests did not differ. Calculations were made to test this hypothesis, and these included forest harvest yield, the percentage of the number of trees harvested in the SFMP using the relationship between the authorized and harvested volumes as well as the numbers of authorized trees and those harvested.The results show that the yields based on numbers of trees and volumes were statistically lower for SFMP in public forests compared to private forests. These results suggest that a significant part of SFMP in private forests could systematically become a source of forest credits used to obtain fraudulent documents for forest products that are illegally harvested, which is referred to as “esquentamento” in Portuguese.

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