回复4楼:有时候烧一下是好事儿，否则一些大树死了还在那边占地方，不利于生态平衡和新陈代谢。。。

山火是自然现象, 累积一段时间后, 就要靠山火来更新. 过去印第安人就会故意,有计划的人为放火. 现在各国也在实验这种方法. 加拿大BC 省就在进行这个试点.
Fire is a normal and natural process in many of B.C.’s ecosystems. Many species of plants, birds, insects and other animals depend on fire for its regenerative properties. Fire helps control insects and the spread of disease in forests. A forest with trees of various ages and species helps create biodiversity
A prescribed fire is lit intentionally. It’s an effective tool for reducing fire hazards because it helps decrease fuel loads (i.e. combustible material, such as underbrush and dead wood) on the landscape. Prescribed fires also help reduce the intensity of future wildfires by removing understory vegetation (i.e. vegetation that grows on the ground underneath the forest canopy).