我们知道,林业是个多因子、多层次、多功能的复杂的大系统。在林业系统中,包含了林业生态系统、林业经济系统和林业技术系统这三个子系统,各个子系统又由不同的因子组成。如林业生态系统包括森林植物、森林动物、森林微生物以及非生物环境,它们相互作用、相互联系、相互制约,构成了具有一定结构和功能的林业生态系统。在林业生态系统中,人既是生态系统的组成部分,又是人与自然界有机统一的主导者。正是由于林业 We know that forestry is a multi-factor, multi-level, multi-functional and complex system. In the forestry system, it contains three subsystems of forestry ecosystem, forestry economic system and forestry technology system, and each subsystem is composed of different factors. For example, the forestry ecosystem includes forest plants, forest animals, forest micro-organisms and non-biological environment, which interact, interrelate and restrict each other and constitute the forestry ecosystem with certain structure and function. In the forestry ecosystem, people are both an integral part of the ecosystem and a leader of organic unity between man and nature. It is because of forestry