北美西部的高山森林需要火灾。为什么呢?这是因为火能够将养分重新返回到土壤中,更替土壤,重新生长新的幼苗。虽然这里的森林火灾并不经常发生——每隔100年到300年一次,但偶尔发生猛烈的大火确实是针叶林的典型特点。1988年,美国黄石国家公园发生了一次严重的森林大火。极端干旱、高温最终给大 Alpine forests in western North America require a fire. Why? This is because fire is able to return nutrients to the soil, replacing the soil, and regenerating new seedlings. Although forest fires do not happen quite often - once every 100 to 300 years, occasional violent fires are indeed characteristic of coniferous forests. In 1988, a serious forest fire broke out in Yellowstone National Park in the United States. Extreme drought, heat eventually give big