Quantitative studies on charcoalification:Physical and chemical changes of charring wood  

作　　者：Gang Li Linlin Gao Fengwen Liu Menghan Qiu Guanghui Dong 

机构地区：[1]MOE Key Laboratory of Western China's Environmental Systems,College of Earth&Environmental Sciences,Lanzhou University,Lanzhou 730000,China [2]Institute for Ecological Research and Pollution Control of Plateau Lakes,School of Ecology and Environment Science,Yunnan University,Kunming 650504,China

出　　处：《Fundamental Research》2024年第1期113-122,共10页自然科学基础研究（英文版）

基　　金：This work was supported by the funding from the National Natural Science Foundation of China(41825001 and 41991251);the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(2019QZKK0601).

摘　　要：Charcoal is commonly preserved in both natural and artificial sediments,and is intensively used in paleontological,paleoenvironmental,and archaeological studies due to the abundant bio-information it contains.The biochemical properties of charcoal are also used for paleoclimatic reconstruction;however,the reliability of this approach has been challenged due to a lack of clarity on how physicochemical properties change during the charring process,as well as the temperatures required for charcoalification.To address this lack,in this study,Qinghai spruce and Chinese pine wood samples from the northeastern Tibetan Plateau were heated at different temperatures and for different lengths of time under restricted oxygen conditions.The reflectance;carbon,nitrogen,and oxygen content;and tracheid morphology were quantified before and after heating to assess changes related to the charring process.Archaeological charcoal remains were then evaluated to determine the charcoalification temperatures by comparing with the experimental results.The minimum temperature required for wood charcoalification was∼300℃,while temperatures recorded by archaeological charcoal were concentrated at 400-500℃.During the charring experiments,the tracheid cell walls gradually homogenized,and tracheid cell wall thickness and lumen area decreased by∼20%.On average,50%mass losses were observed;the carbon and oxygen content(%wt.)approximately changed from 47%to 60%and 48%to 35%respectively,while the nitrogen content(%wt.)fluctuated around 0.2%.The reflectance increased slightly from 0%to 0.5%.We propose that the charcoalification of wood tissue refers to charring(in restricted air)and carbonization(in the almost absence of air)when the wood is exposed to a heat source,which then finally transforms into a black,inert solid.This quantitative study provided valuable data and a thorough assessment of the process of wood charcoalification,as well as accurately estimated the feasibility of using charcoal physicochemical properties in paleoclimatic

关 键 词：Charcoalification Quantitative study Charcoal formation Archaeological charcoal Tracheid cell wall thickness Reflectance 

分 类 号：TQ127.1[化学工程—无机化工]