The Annex Experimental Area Manuel Belgrano is located in Misiones under INTA administration. This forest management unit comprises an Araucaria angustifolia plantation forest, with a significant productive and conservation value. The objective of this study was to apply the methodology of Principles, Criteria and Indicators to evaluate the sustainability at Forest Management Unit level. Our results show that the staff forms a well-integrated group, in which its leaders are aware of the environmental importance of the place. On the other hand, the fact that some information is handled only by some actors added subjectivity to the proposal studied.