The National Park Service estimates that in natural conditions, grasslands in Yellowstone burned an average of every 20 to 25 years, while forests in the park would experience fire about every 300 years.
国家公园管理局估计在自然条件下，黄石的草原平均每20至25年就会被烧掉一次，而公园内的森林则平均每300年就会经历一次大火。