The Ecological Status and Uses of Ricinodendron heudelotii (Baill.) Pierre and Gnetum Species around the Lobeke National Park in Cameroon

Abstract

Ricinodendron heudelotii (Baill.) Pierre (Euphorbiaceae), Gnetum buchholzianum Engl. and Gnetum africanum Welw. (Gnetaceae) are among the major species of non timber forest products (NTFPs) of the Lobeke National Park (LNP). The growing demand for these products has led to an increase in exploitation; but no information exists on the status of the resource base. There is equally very little information on the importance of these resources to the local population. A survey was conducted in 152 households to get the perception of locals on the availability and use of these resources in the Lobeke landscape. An inventory was also conducted to determine the abundance of the species in three forest systems including protected area, production forest and agroforest. Productivity of Ricinodendron heudelotii was assessed by counting fruits from fifteen trees in each forest system. 88 % of respondents collected Ricinodendron heudelotii, mostly for sale and earned between 69300 and 1002000 FCFA per year. All respondents collected Gnetum leaves, and up to 35 % of collectors solely for consumption. Sale of Gnetum leaves ranged from 200 to 9200 FCFA per week. 99 % of collectors thought that the quantity of Gnetum in the wild has reduced over the years while Ricinodendron heudelotii is still abundant. There were more trees of Ricinodendron heudelotii in the production forest and agroforest than in the protected area. No significant difference was observed in mean diameter at breast height (DBH) of trees in all forest systems. Mean number of fruits was significantly higher for trees in the agroforest than for those in the production forest and protected area. A significantly higher number of Gnetum buchholzianum vines was observed in the production forest than in the agroforest and protected area while the growth of Gnetum buchholzianum seedlings were significantly lower in the agroforest than in the protected area and production forest which showed no significant difference. The presence of productive individuals of Ricinodendron heudelotii is an indication that the resource will be available for some time but the near absence of younger individuals is unfavorable for the perpetuity of the species. It is recommended that the local population be sensitized on the importance of domesticating these species and trained on appropriate techniques to propagate and incorporate them into suitable agro systems.