Forest depletion (deforestation and forest degradation,) has occurred in indigenous homelands over several thousands of years, and it is ongoing in many forests. More than 1400 distinct indigenous peoples living in the world’s tropical and sub-tropical ecosystems (Tauli-Corpuz, 2008 and 2009), most of whom are hunters, gatherers, and rotational agriculturalists or shifting cultivators encroach on forest for their agro-pastoral activities. The study investigates drivers of forest depletion and its consequences in the contiguous Ngongbaa-Kilum, forest area in Bui Division in the Northwest Region of Cameroon. Data was collected from 10% of the 8416 households of the 2005 census data (BUCREP, 2005) spread in 21 villages at the fringes of the contiguous Ngongbaa-Kilum forest Two sets of data were used for this study, primary and secondary data. Primary data comprises responses of respondents to questionnaires, interviews, focus group discussions, inferential and experimental data. We used the Base map of Nkambe, satellite images GPS survey data to evaluate spatial land cover change. Participatory mapping was carried out using GPS receivers to update topographic map and satellite data. The findings show that the depletion the Contiguous Ngongbaa-Kilum forests between 1963 and 1987 was caused by exploitation of Prunus africana, coffee and food crop farming, invasive eucalyptus, the fall in coffee prices in the 1980s; and the Irish potato boom. This led to the reduction of the Ngongbaa forest from 5780.6 hectares in 1963 to 2977.6 hectares in 1987 (reduction of 48.5%) while the Kilum section reduced from 19119.3 hectares to 8127.9 hectares (reduction of 61.4%). Consequently, the density, heights and sizes of trees also reduced. Larger mammals like leopards, buffalos, gorillas etc. are extinct. The depletion of this forest also engendered climate change, reductions in volumes of streams, migration of organisms, fluctuation of weather, and decaying of crops. This obliged the Cameroon Government in collaboration with international partners to create the KMFP in 1987 to conserve the contiguous Ngongbaa-Kilum forest. This project that was later renamed Kilum-Ijim forest project in 1992 took over the management of the forests from the Nso and Oku people, delimited the forest boundary, conserved the forest, raised local peoples’ capacities and conservation concerns, carved the forest into 5 community forests and transferred their management to FMIs in 2004. Deforestation and forest degradation have reduced to their lowest ebb with minor cases of encroachment into the forests by frontline farmers. To maintain the forest limits, study recommends that, the state in collaboration with the local communities should replace the Prunnus africana tress that withered after illegal exploitation with non-economic trees that develop thick canopies that can inhibit undergrowth, resist fire and discourage frontline farmers from encroaching into the forest. Also, alternative resources should be icreated through agro-forestry. Furthermore, a reforestation program should be established in order to restore degraded portions of the reserve area