Despite the environmental, social, and economic advantage of using forest biomass as fuel, forest biomass supplies are under-utilized at the moment. Some barriers that restrict the use of forest biomass for producing energy are seasonal variations in biomass availability, limited availability and high production costs of biomass, existing technical limitations (e.g. conversion efficiency) and complex and costly fuel supply chain logistics,which is because of some physical characteristics of forest bio-mass. Low bulk density of biomass, which ranges from 50 to 130 kg m