Energy properties of the biomass of Acacia mearnsii De Wild. In differents ages and sites of cultivation

The quality of biomass used as raw material in energy generation depends on properties such as: basic density, gross calorific value, volatile matter content, fixed carbon and ashes. Thus, the objective of this research was to evaluate the effect of cultivation site and age, as well as their interactions, on such properties of Acacia mearnsii tree biomass. In order to reach the objective, commercial stands of the species were randomly sampled at four ages and at three cultivation sites. Each individual had its biomass separated in crown and stem to determine the energy variables in the laboratory, as well as the total biomass. For crown and stem the basic density values ranged from 0.44 to 0.58 g cm-3, from volatile materials between 69.09 and 77.55%, from fixed carbon between 21.54 and 27.68%, from gray between 0.73 and 3.80% and gross calorific value between 4,518 and 5,089 kcal kg-1. The energy properties of both crown and stem biomass were influenced by the cultivation site and the age of the stands. The interaction between the factors was significant for most variables. Biomass from all stands can be used for energy purposes, however, older stands are more appropriate. © 2021 University of Sao Paolo. All rights reserved.