Plant Exploitation And Vegetation Change At Dadiwan Site During 7000-5000cal KaBP,Reliminary Results Of The Charcoal Analysis

Whether in ancient times with low level of productivity or in mordern with a high level of productivity,wood has a main rescource exploited by the human populations.It is because of the closed relation of tree and human.Charcoal analysis is a effective method to study the relationship between humans and the environment.The dadiwan site,in the western Loess Plateau,Gansu Province,is one of the most famous archaeological sites in the Loess Plateau in China.From August 2014 to January 2015,dadiwan site was excavated by a joint team of Gansu Provincial Institute of Antiquity and Archaeology and Lanzhou University.Wood charcoal was scattered in variable features throughout the excavated deposits.Flotation techniques were used to retrieve charcoal remains from cultural periods and numberous charcoal were identified and quantified.The total number of 1319 charcoal were identificated from culturcal layers,pits,housing sites,post holes,fireplace,etc.Our results showed that excavations during fieldworks at dadiwan had yielded numerous charcoals.The species includeQuercus,Qstya,Coryclus,Aluns,Carpinus,Picea,Taxus,Betula,Acer,Tilia,Fargesia,Rosaceae,Melia,Populus,Cercidiphyllum,Fagus,Morus.A long sequence and high resolution of charcoal assembly was established from 7000 cal BP to 5000 calBP and showed the information about vegetation change.The results showed that the identified speciecs were consistent with the constructive species in this region except some species like Taxus and Melia.During the early times,the proportion of Quercus and Qstya was the largest in dadiwan site;The abslute number of Quercus was larger than the Qstya,and other species spread in nearly every culturacal layers and fetures,such as Acer,Tilia,Fargesia,Rosaceae,Melia,Populus,Cercidiphyllum,Fagus.During the late dadiwan period,the species and proportions had changed,the proportion of Quercus declined compared to the proportion of Qstya.Other species had reduced or even disappeared,which indicated that the environment around the dadiwan site had been eteriorating might because of the exploitation by human.In addition to the vegetation asembly,We also mainly analysis the charcoal from fireplace,pits,housing,postholes respectively.The results also showed that Quercus and Qstya were the most important species in the mid-Yangshao human livies of dadiwan site.Other species such as Morus found in the floor of the houses,it might be used for the food and medicine,indicating that wood were selective by human.So this help us understand the way how past human explotated the wood around the dadiwan.