全世界每年发生森林火灾约20万起,烧毁森林五六百万公顷,约占森林总面积的千分之一,而人为火灾约占90％,人为火灾发生频数一般与居民密度成正相关。 林火等级是以燃烧林地面积来划分的: 一般火灾:10—999亩 大火灾:1,000—50,000亩 特大火灾:50,000亩以上 一九五○至一九八四年,我国发生五十五万余次森林火灾,烧毁山林五亿余亩,成灾面积一亿八千余万亩。相当解放后我国人工造林面积的43％。 About 200,000 forest fires occur each year in the world, burning 56 million hectares of forest, accounting for about one thousandth of the total forest area, while man-made fires account for about 90% of the total. The incidence of man-made fires is generally related to the population density. The fire rating is based on the area of ​​burning woodland: Normal fire: 10-999 mu Large fire: 1,000-50,000 mu Large fire: 50,000 mu or more From 1950 to 1984, more than 550,000 Forest fires, burned more than 500 million mu of forests, disaster area of ​​more than 180 million mu. After the liberation of China’s afforestation area of ​​43%.