中文摘要：

利用树木年轮年代学方法,以大兴安岭北部塔河林业局盘古林场13个兴安落叶松（Larix gmelinii）树轮火疤圆盘为基础,通过交叉定年重建了该地区235a的火灾历史.对火灾数据的分析表明：盘古地区兴安落叶松林的平均火灾间隔期为31.6a,火灾轮回期为45.4a.林火以早材火为主,占该地区火灾总数的95%;晚材火和休眠火所占比例较小,仅为5%.对盘古地区火灾发生与气候因素的关系进行的分析表明：帕默尔干旱指数（Palmer droughtseverity index,PDSI）与火灾发生当年的叠加点事件分析（superposed epoch analysis,SEA）达到在95%的显著水平,即气候越干旱,盘古地区火灾发生的可能性越大.火灾前几年相对湿润的气候条件也为林火发生提供了必要条件,而且连续的干旱可能导致森林大火的发生.此外,长时间尺度的国家政策或人为干扰对火灾发生也有影响.

英文摘要：

Daxing＇an Mountains is the largest forest distribution area in China and also the forest fire- prone area. Forest fire is the most important natural disturbance factors for forest ecosystems, and causes serious harms to both forest environments and human beings. Therefore, it is very critical for us to know the long-term forest fire regime in this area. A 235-year forest fire chronology was built by using 13 cross-dated tree-ring fire scar discs of Larix gmelinii in Pangu of the northern Daxing＇an Mountains,China. All fire-scar data were input and analyzed using software FHX2. The results showed that the mean fire interval of Larix gmelinii forest in Pangu was 31.6 a,and the number of years per fire was 45.4 a. The major type of forest fires in this area was earlywood fire,which accounts for 95% of all fires. The proportion attributed to latewood fire and dormant fire was rather small, only 5 %. Furthermore,the climate-driven mechanism of forest fires in Pangu was analyzed. The results showed that Palmer drought severity index （PDSI） was significant at the 95% confidence interval at fire year by using superposed epoch analysis. In other words,the possibility of forest fire occurrences in Pangu increased as climates became dry. The relatively humid climates in the years before fires were also a prerequisites for fire occurrences. Moreover, a long-term drought might lead to a huge forest fire. Anthropogenic activities and national policies would also affect fire regime in long-term scales.