The Karthala Forest (Comoros) is currently the subject of a national protection policy, in conjunction with the international community. This policy may be more or less in line with the perceptions and expectations of the residents of the forest. In order to better understand these issues, we have studied the representations of the forest by local populations, upstream of its protection. The following assumptions are made: (i) the degree of knowledge of the components of the forest is different according to the trades, the gender, the age and the ways of frequenting the forest; (ii) the successful establishment of the protected area of the Karthala forest is based on taking into account the representations and uses of the forest by local residents. Surveys carried out in 2016 and 2017 in eight localities around the Karthala forest and in the capital Moroni have allowed us to capture the representations of the components of the forest and the protected area creation project. The collected data were collected in the form of cognitive maps and freelisting. From these data, we constructed an index of the cognitive complexity of each respondent in relation to the forest, which we compared between socio-professional categories, age categories, gender and place of residence. We also compared the social representations of the forest between the residents and the inhabitants of the capital. Our results show that the cognitive maps approach improves the discussions around environmental public policy for both pragmatic and ethical reasons and allows us to study reconciliation issues between conservation objectives of biodiversity and biodiversity, human development of territories.