Periodic fires are an integral part of the rangeland ecology but when the rangeland is still dominated by native grasses fires occur in some areas at average intervals of every 60 to 110 years.是什么意思_Periodic fires are an integral part of the rangeland ecology but when the rangeland is still dominated by native grasses fires occur in some areas at average intervals of every 60 to 110 years.在线翻译_英语_读音_用法_例句