燃やす
environmental
alternative
ardent
background
biofuel
biological
biomass
boiler
central
children
chips
conservation
domestic
eco
ecofriendly
ecological
ecology
economy
efficiency
energy
environment
fire
firewood
flame
friendly
grain
green
heap
hot
house
mass
material
natural
nature
pine
plate
power
renewable
sawdust
source
stove
straw
temperature
timber
view
warm
waste
winter
wood
wooden