Tree-ring Reconstructions Of Fire History And Their Relationships With Human Activities In Daxing’an Mountains

Fire-scars from Daxing’an Mts. region are the data sources of reconstruction fire-scar chronology; collecting areas are Mangui, Pangu, Mengkeshan, Walagan and Hanjiayuan. The five sample plots Larix gmelinii chronologies were established by Using the method and theory of dendrochronology. Mengkeshan area’s Scots pine chronology was established independently. By mean s of fire-scar chronology we found fire frequency was obviously increased from19century middle period in this area. At the same time, the five sample plots’ Fire Interval and Number of years per fire were27.0and44.2,31.6and43.7,24.8and86.3(MKS-P),28.1and69.0(MKS-L),22.7and35.8,22.3and37.5. By means of the fire data we found that this areas’ fire was frequent, but the fire frequency of Mengkeshan area was lower than other four areas. Through the analysis of the fire season we found dormant fire and early earlywood fire were the main fires occurring season in this area.Through the fire-scars chronology of Daxing’an Mts. region, we understood the fire general law of the region. According to the time range of the fire changes, we collected and summarized humanity activity data of different history period, and then conducted correlation analysis for them. Through contrasted research we found Daxing’an Mts. region’s fire frequency obviously occurring fluctuation and change in some particular human activity historical period. When we analyzed the relationships between dynastic policy and fire, we found that fire frequencies were obviously impacted in different policy implementation period. Among the different policies, the fire-scar number each year and the percentage of years with fire were0.12and12%(Prohibition Policy),1.04and39%(Release of Prohibition Policy),2.16and74%(Immigrant and Assart Policy),2.47and67%(Colony Policy),0.88and52%(gradual development policy),0.65and19%(Fire Prevention Policy). In the analyses of wars and fire, we found fire frequency obviously occurring increase and decrease during or after period of the war. In the analyses of immigration and fire, we found that fire basically showed an increasing trend in the immigration peak period. In the analyses of logging and fire, we found fire obviously occurring changes in different felling stages and different felling methods. At the same time, there were a number of other human factors that also led to fire, such as smoking.Through the establishment of fire-scars chronology and analysis between human activities and fire, we found fire laws were less-more-less in Daxing’an Mts. region and this law has been obviously impacted by human activities.