Energy value as a factor of agroforestry wood species selectivity in Akinyele and Ido local government areas of Oyo State, Nigeria

Wood usage for cooking and heating is still very relevant in most developing countries especially those of sub-Saharan Africa and many parts of Asia. Therefore, sustainable means of generating it for this and other purposes are necessary bearing in mind the influence of indigenous knowledge/users' perspective on any production method regarding success and sustenance. In conformity with this view, questionnaires were administered on 240 respondents in 8 rural communities of Akinyele and Ido Local Government Areas (LGAs) of Oyo State, Nigeria, to elicit information on species that can be used as fuelwood, preferred by the respondents for incorporation into and/or retention in agroforestry plots, out of which 179 (i.e. 75% of the total number of questionnaires administered) were successfully retrieved for statistical analyses. Twelve woody species namely: Annona senegalensis, Anogeissus leiocarpus, Bridelia ferruginea, Daniellia oliveri, Detarium microcarpum, Gardenia ternifolia, Hymenocardia acida, Lophira lanceolata, Parkia biglobosa, Terminalia avicennioides, Triplochiton scleroxylon and Vitellaria paradoxa were prioritized on the basis of respondents' preference using a ranking pattern. Friedman chi-square analysis showed that there was no significant difference (p < 0.05) in the ranking pattern of the respondents from the two LGAs. The mean net calorific values (NCV) of the 12 species were found to be 17.71, 18.63, 18.04, 16.03, 17.67, 18.46, 19.00, 21.68, 19.63, 18.25, 14.65, and 19.47 MJ kg−1 respectively. The result of a two-way analysis of variance indicated a significant variation (p < 0.05) in NCV data for all the species pooled together but not for each species except for D. oliveri with a follow-up test using Fisher's Least Significant Difference. The Pearson's moment correlation analysis gave positive coefficient values (r = 0.868 and 0.874, p < 0.05) between NCV and the cumulative ranking values in Akinyele and Ido LGAs respectively. There was also a coefficient value of 0.873 (p < 0.05) between the cumulative ranking values in the two LGAs. In line with the outcome of this study, it was therefore recommended that native intelligence/indigenous knowledge and/or users' perspective should be part of the criteria for selecting potential fuelwood species for incorporation into and/or retention in agroforestry systems in this and other areas with similar characteristics.