This paper is concerned with indigenous knowledge of forest management among the Gedeo people of southern Ethiopia and factors that enable them to manage their tree species. Specifically, it deals with the congeniality between celebrating festivities of an individual’s rite of passage and planting varieties of tree species within the framework of their livelihood strategies. Then, the paper deals with the challenges they often encounter in maintaining these cultural practices. Relevant qualitative data were obtained from both primary and secondary sources. Key Informant interview and In-depth Interview, respectively, with community elders and farming household heads and Focus Group Discussions were conducted at three kebeles (local level administration) of Wonago Woreda (district). The data were analyzed through considering the different data sources to present the study findings. The study found that Gedeo people have effectively managed their forest resources due to the supervision of indigenous Gadaa institutions, their effective land use and management, and their worldview and belief system towards natural resources. Above all, in Gedeo, there is often congeniality between planting trees and individuals’ rites of passage. This association enabled them to continuously manage their trees and forests and make their living on them in the form of what is known as agroforestry.