MORPHOLOGICAL ANALYSIS AND ENVIRONMENTAL SIGNIFICANCE OF CHARCOAL IN MODERN MOUNTAIN FIRE IN YUNNAN PROVINCE
As one of the most important agents in shaping earth landscape,the fire regime plays a significant role in the evolution of terrestrial ecosystems and human societies.With the continuous increasing of extreme fires all over the world,the reconstruction of fire history and its driving mechanism based on charcoal is of great significance to governments and scientists.In this paper,we chose 4 sample sites to collect charcoal samples from modern mountain wildfires that occurred in Yuxi,Yunnan Province.The site A(24°20′39″N,102°40′37″E)and site B(24°20′49″N,102°40′47″E)are located in Pinus yunnanensis forest,and the site C(24°20′48″N,102°40′45″E)is in Miscanthus sinensis grassland.The site D(24° 19′52″N,102°40′59″E)is located in an unburnt area.By obtaining charcoal fragments through pollen extraction method,and measuring them with ImageJ software,we analyzed the difference in charcoal morphology and size between different vegetations.Our result shows that the morphology of charcoal from Pinus yunnanensis forest is predominately square and round,with flat edges,and the average length and width are 25 μm and 17 μm respectively.The mean acreage is about 326 pm2.For the charcoal from the Miscanthus sinensis grassland,its morphology is much different to that of Pinus yunnanensis forest and the size is relatively smaller.The morphological types are mostly elongated,with irregular edges and the average length and width are 11 μm and 8 μm respectively,with the mean acreage at about 74 μm2.It is worth noting that the length-width ratio of charcoal fragments from two vegetation types is close,mostly between 1.0～2.5,indicating that the length-width ratio is not an effective index to distinguish charcoal from woods or herbs.Meanwhile,the later taphonomic processes exerted an evident impact on charcoal size,as the mean length,width and acreage all decreased,while the length-width ratio remained stable.Based on the analysis of charcoal from different plants under wildfire,this study highlights the importance of both charcoal morphology and size in differentiating fuel sources,and provides important clues to the complex relationship between the fire regimes and vegetation.
万方数据
维普
