FIRE HISTORY OVER THE PAST MILLENNIUM REVEALED BY THE CHARCOAL RECORD FROM LAKE ERHAI,NORTHWESTERN YUNNAN PROVINCE
Yunnan Province is one of the typical fire-prone regions in China.Understanding the evolutionary history and driving mechanisms of palaeofire over the past millennium in this region is of great scientific significance for both forest fire prevention and biodiversity conservation in the future.In this study,we collected three sediment cores(coreEHBl at 25.84° N,100.18° E,58.5 cm;core EHN1 at 25.66°N,100.24° E,78.5 cm;core EHB2,80 cm)from Lake Erhai(25.60°～25.96° N,100.08°～100.30° E;1974 m a.s.1)to reconstruct the palaeofire history in northwestern Yunnan Province based on the high-resolution charcoal records,and combined with the 210Pb/137Cs and AMS 14C dating techniques for constructing the chronological framework.The results indicate that the fire episodes constructed by the macroscopic charcoal record from Lake Erhai were consistent with the documents of modern forest fires.It was determined that the macroscopic charcoal record reflected the fire activity of Dali City within about 10 kilometers around the lake,and the feasibility of utilizing charcoal records to reconstruct the palaeofire activity was validated.A total of 20 fire episodes were identified from the charcoal record,which was mainly concentrated in 1200～1350 A.D.and 1540～2000 A.D.The intensity of palaeofire activity in Lake Erhai area decreased first and then increased over the past millennium,of which the frequency and intensity of fire episodes within the last century reached the highest values over the past millennium,corresponding to 10 fires 300 a-1 and 652.4 particles/cm2/peak,respectively.The fire returns interval showed a roughly out-phase change compared to the fire frequency,which reached the peak at 1420 A.D.,corresponding to 80 years.The Pearson correlation,Redundancy analysis(RDA),and comparative analysis between the charcoal records,palaeofire activity from Lake Erhai,and the regional high-resolution climate records,vegetation conditions,and historical documents show that the population change in Dali prefecture is the most important driving factor of palaeofire activity in the Erhai area over the past millennium,followed by regional rainfall and vegetation type,whereas temperature and plant biomass less influence on the palaeofire activity.The correlation coefficient between the population in Dali Prefecture and the charcoal accumulation rate(and fire event frequency)is 0.55(and 0.71),and the explanation degree of the population in Dali Prefecture to the charcoal accumulation rate and fire frequency can reach 30.5％and 50.9％,respectively.
charcoalfire historyclimate variationhuman activitylake sedimentnorthwestern Yunnan Province
万方数据
维普
