Evaluation of Proximate Properties and Heating Values of Wood and Bark Content of Five Common Firewoods in Yobe State, Nigeria

The study determined the influence of proximate properties and heating values of wood and bark contents of five different firewood species. The experiment was conducted with a view to resolve the indiscriminate use of firewood with and without bark contents for energy values by the people in the study area. Majority of the people depend on firewood as a source of energy for domestic and commercial uses. Five different firewood species samples were obtained at three different locations at Damaturu, Yobe State. Each of the tree species was cut at 25 cm long and replicated three times. Therefore a total of fifteen firewood species samples were used for the study. The wood and bark were independently subjected to proximate analysis using ASTM standards. Meanwhile, the statistical test was performed using ANOVA and Duncan’s multiple range test (DMRT). The results of the study reveal that the high volatile matter was obtained in a wood portion of Sclerocarya birrea with 83.03% while a lower value of 75.19 % was found in Combretum lamprocarpum while its bark portion was found to be 65.69 % in Combretum lamprocarpum and lowest value of 44.69% was found in Piliostigma reticulatum. The variation in ash contents of wood portions ranges from 0.16% in Acacia sieberana to 0.46 % in Sclerocarya birrea. Conversely, the bark portion ranges from 5.36% in Tamaridus indica to 6.15 % in Acacia sieberana. The fixed carbon content of wood ranges from 16.51% in Sclerocarya birrea to 26.26% in Tamarindus indica, while 29.76 to 47.49% was recorded from bark portions. The heating value of the wood portion was found to be 33.48 Jkg-1 in Sclerocarya birrea to 33.65 Jkg-1 in A. sieberana. On the other hand the bark portion of 31.27 Jkg-1 was obtained in P. reticulatum and 32.22 Jkg-1was recorded from C. lamprocarpum. It is concluded that the bark content of wood insignificantly affects the proximate properties and heating value of firewood species.