The biomass obtained from eucalyptus forestry residues can be used as fuel for industries. It is a renewable energy and has advantages such as high amount of material and low cost. The aim of this research was to perform the physico-chemical characterization of eucalyptus bark used for power generation in a panel industry, and identify the existence and the components of the contaminants in the bark. Three treatments were performed for particle sizes of peel: T1 (850µm and 425µm), T2 (250µm) and T3 (<150µm). The material was assessed for moisture content and the three treatments were subjected to chemical analysis. Also, the high heating value was calculated. The ashes were analyzed under scaning electronic microscope (SEM) and energy dispersive spectroscopy (EDS) in order to identify the contaminants. All treatments showed contaminants in their ashes, with the presence of Ca, Fe and Si. The data obtained in this study were statistically analyzed using the software R. The material presented moisture content of 70% on a dry basis, considered high for use in bioenergy. The ash content and volatile content presented significant difference between treatments, and T1 showed lower value for ash (2.63%) and higher value for volatile (80.23%). The treatment T1 was considered best for use in energy purposes.