人类的生产发展史就是一部物质综合利用史,无论是煤炭、石油、还是金属、木材,都毫无例外地遵循着这一自然规律和经济规律。石油和木材在开发初期,都主要是当做燃料消耗掉的,随着人们对自然界的认识的逐步深化,现在则都在日益转化成为重要的加工原料,尤作燃料消耗的比重正在明显地日趋下降,特别是木材,在林业发达国家,百分之几十以上 The history of human production and development is a history of the comprehensive utilization of materials. Whether it is coal, oil, metal or wood, we follow this natural law and economic law without exception. As oil and timber were mainly consumed as fuel at the early stage of development, as people’s understanding of nature gradually deepened, they are now increasingly being converted into important raw materials for processing. In particular, the proportion of fuel consumption is apparently declining In particular, timber, in developed countries, more than a few dozen percent