Comparison of calorific values and physico-chemical properties among three age groups and height positions of Acacia decurrens (Willd)

Energy is a vital societal resource regardless of socio-economic status. A continuous increase in energy demand coupled with environmental degradation exerts pressure on the forests of developing countries. Hence, introducing fast-growing trees such as Acacia decurrens Willd as an alternative bioenergy plant is of paramount importance. One of the criteria that favors the species being used as a potential candidate as fuel wood is its relative performance in releasing high energy. The study compares the energy content of A. decurrens at three consecutive ages: 3, 4 and 5 years. Pellets were prepared from sampled discs of the three ages taken from the bottom, middle, and top positions of the sampled trees. To determine the difference in calorific value between groups, a 2 × 2 factorial ANOVA was used. The energy content was determined using an oxygen bomb calorimeter (Model 6200 isoperibol calorimeter). Apart from energy content, proximate analysis was also analyzed with moisture content ranging from 7.3 to 8.3 percent, volatile matter from 15.0 to 26.3 percent, and ash content from 0.33 to 0.66 percent, and basic wood density from 0.321 to 0.842 g/cm³. The mean calorific value of the three ages ranged between 19.99 and 21.35 MJ/Kg. The moisture and ash content were insignificant in terms of the species’ calorific value. The results of the analysis of variance revealed that the there is marginal difference in the interaction effect and disc position with p values equaled 0.065 and 0.207, respectively. This study indicated that tree age did not have much influence on caloric values and physico-chemical properties of the studied species.