燃やす
environmental
alternative
alternative energy
bio
biofuel
biology
biomass
biotechnology
brown
chips
compressed
conservation
eco
ecological
economy
energy
environmental conservation
fire
fireplace
firewood
flaming
friendly
fuel
green
hardwood
heating
isolated
leaf
mass
material
measurement
natural
organic
pellets
power
product
recycling
renewable
renewable energy
resource
sawdust
solid
source
stove
sustainable
warm
wood
wood pellets
wooden