燃やす
environmental
alternative
background
bio
biofuel
biological
biomass
central
chip
conservation
domestic
eco
ecologic
ecological
ecology
economy
efficiency
energy
environment
fire
firewood
flame
flaming
friendly
fuel
generation
grain
green
heap
heat
mass
material
natural
nature
pellet
pile
pine
power
recycling
renewable
sawdust
solid
source
stove
timber
view
waste
wood
wooden