In this document, we first present the rationale and objective of the BLACSI approach. Next, we describe the context where BLACSI was tested, i.e. the two villages in Berau that were engaged in the Berau Forest Carbon Program ("the Berau Program"), a district-wide program to reduce emissions from deforestation and forest degradation. Then, we describe the rapid assessment methodologies used. Finally, we present key lessons drawn from our experience.