Ключевые слова: alternative, ardent, bio, biofuel, biological, biology, biomass, boiler, burn, central, closeup, eco, ecology, economy, energy, environment, fire, fireplace, flowing, fuel, heap, heat, industry, leaf, mass, material, nature, pellet, pressed, recycling, renewable, roll, roller, seasonal, solid, stove, texture, timber, warmth, wood, wooden,