To contribute to the accurate assessment of carbon of agroforest species of Sudano-sahelian ecosystems, a study based on the establishment of mono-specific allometric equations were investigated in the arboreous parks of the Far-North Cameroon. A total of 20 individual trees of Faidherbia albida was harvested in savannah and distributed across a range of diameter classes, from 10 to 60 cm. The diameter at breast height of these individuals and their height were measured. After tree cutting, biomass of compartments of leave, branches and stem were determined after drying and weighing. Various allometric equations between biomasses and two parameters of the tree (the diameter and the height) were tested. The adjusted coefficient of determination (R2adj), the residual standard error (RSE) and the Akaike Information Criteria were used for choosing the best models. The main results reveal that there is a positive and significant relationship between the height of the trees and their diameter (R2 = 0.75, n = 17 and P < 0.05). The best model for the biomass prediction of all compartments of F. albida is in the form ln(B) = a + b*ln(D2H), with ln(B) = -1.42 + 0.58*ln(D2H) for leaf biomass, ln(B) = - 5.83 + 1.11*ln(D2H) for the branch, ln(B) = - 4.01 + 0.94*ln(D2H) for the stem, and finally ln(B) = -2.83 + 0.91*ln(D2H) for the total biomass. Their adjusted coefficient of determination is 0.71, 0.90, 0.93 and 0.93 respectively. The branch biomass represents about 42.16% of the total aerial biomass and is the highest relative to the other compartments. Theses equations bring a contribution to a reliable and quick assessment of carbon stock of arboreous parks to F. albida in the framework of study on climate change mitigation in Sudano-sahelian zone in particular and in the World in general.

Little information on allometric relationships for estimating stand biomass in the savannah of Cameroon was available. Allometric relationships for estimating stand biomass were investigated in the sudano-guinea savannah of Ngaoundere, Cameroon. A total of 90 individual woody from sixteen (16) contrasting plant species belonging shrubs and trees were harvested in Dang savannah across a range of diameter classes, from 3 to 35 cm. Basal diameter (D), total height (H) and tree density were determined and considered as predictor variables, while total above-ground biomass, stem, branch and leaf biomass were the output variables of the allometric models. Among many models tested, the best ones were chosen according to the coefficient of determination adjusted (R2adj), the residual standard error (RSE) and the Akaike Information Criteria. The main results showed that the integration of tree height and density with basal diameter improved in the degree of fitness of the allometric equations. The fit allometric stand biomass model for leaf, branch, stem and above ground biomass were the following forms: Ln(LB) = -5.08 + 2.75*Ln(D) – 0.30*Ln(D2Hρ); Ln(BB) = -7.81 + 1.29*Ln(D2H) – 0.39*Ln(ρ); Ln(SB) = -5.08 + 2.40*Ln(D) +0.50*Ln(H) and Ln(TB) = -5.07 + 3.21*Ln(D) – 0.12*Ln(D2Hρ) respectively. It is concluded that the use of tree height and density in the allometric equation can be improved for these species, as far as the present study area is concerned. Therefore, for estimating the biomass of shrubs and small trees, the use of basal diameter as an independent variable in the allometric equation with a power equation would be recommended in the Sudano-guinea savannahs of Ngaoundere, Cameroon. The paper describes details of shrub biomass allometry, which is important in carbon stock and savannah management for the environmental protection.

In order to identify the woody species indicators of soil fertility according to farmers' perceptions and to determine the socio-economic importance of these woody species, a survey was conducted on one hundred and fifty (150) farmers within the Ngaoundere III rd Municipality, Adamawa Cameroon. Results indicate that on the seventeen (17) woody species identified by the farmers as soil fertility indicators, six (6) were the most abundant cited whose three (3) mimosaceae (Entada africana, Parkia biglobosa, Albizia zigia), one Combretaceae (Terminalia macroptera), one Clusiaceae (Harungana madagascariensis), and one Myrtaceae (Syzigium guineense var. macrocarpum). These woody species as indicators of soil fertility also played an important role in the socio-economic life of famers because they gave food, sanitary, fodder and are also used to make some kitchen tools or serve as building materials. Vitellaria paradoxa, Parkia biglobosa, Annona senegalensis, Ximenia americana, Ziziphus mauritiana and Piliostigma thonningii were refered as the most diversely used by population of Dang. These results will enable the integration of farmer knowledge in the new technology of the improvement soil fertility and for the farmers to benefice the services given by these woody species.