大兴安岭原始林区林木火疤的研究

Study on fire scar of trees in Daxing′ an Mountains′ virgin forest region

通过对火疤木的调查与分析,研究了大兴安岭北部原始林区的森林火历史。该地区平均森林火间隔期为37.2a;兴安落叶松对火具有抵抗能力的最低树龄约为30a,之后其抗火能力逐渐增强,当达到80a生左右时,其抗火能力最强,这一最佳抗火时期可持续到150a左右。树龄在110～150a之间的火疤木株数占火疤木总株数的近60%,说明大兴安岭森林火有近一半以上是110～150a前发生的;树龄大于150a的可认为是森林火后的保留木,这部分林木仍占目前林木株数的近30%,说明当时大面积森林火过后至少有40%～50%的树木未被烧死。树龄小于70a的火疤木没有分布,说明大兴安岭北部原始林区1987年以前至少近40a无大面积森林火发生。

Based on the analysis of fire scars, the fire history of the Daxing′an mountains′ virgin forests is studied in this paper. The mean fire interval in this region is 37.2 years.The lowest age of larix gmelinii trees with fireresistant ability is about 30 years old. The trees can resist moderate to high intensity fires when they are about 80yrs old. This golden period for resisting fires can last to 150yrs old. About 60% of the fire scar trees are 110 to 150yrs old in the region. It shows that most of the forests fire happened at that time. There are 30% fire scar trees more than 150yrs old. This shows that there are at least 40% to 50% trees survived after large fire. There are no fire scar trees with age below 70yrs. It illustrates that there is no large disastrous fires for 40yrs before 1987 in this region. 