The depletion of forest resources in developing countries affects more than 1 billion people who depend on forests for their livelihoods. Support to forest conservation initiatives is increasing, as well as the interest in studying the drivers underpinning projects' success. In this multidisciplinary article, we analyse how and to what extent the wealth of household assets, defined following the Sustainable Livelihoods Framework, influences the long-term outcomes of initiatives aimed at promoting improved forest management practices. Based on a unique dataset from household survey data collected in Guinea, an economic-statistical analysis is conducted in order to determine how such assets influence the achievement of projects' long-term outcomes. The results reveal that human, social and financial capitals greatly affect the attainment of positive results related to planned interventions. As a main outcome of the study, every project should consider, in the design phase, the status of the households' livelihood assets within the target area, as they are shown to be crucial for projects' success.