The Use of Volume Yield and the Number of Trees to Control Forest Management Operations and Combat Illegal Harvesting

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.