我国林木剩余物储量估算及其潜在温室效应
Assessing potential availability of forest residues and the associated contribution to climate change
在化石能源导致的能源短缺和气候变化的背景下,越来越多的国家鼓励将林木剩余物用作能源。然而,由于数据的可用性和研究方法的局限性,很难在精细的空间尺度上量化林木剩余物,因此,研究我国县域尺度的林木剩余物储量及气候变化贡献具有重要意义。在本研究中,我们建立自上而下的模型估算中国 2018 年林木剩余物储量,并基于林木剩余物的分解过程,量化林木剩余物分解带来的碳排放量,评估其对气候变化的贡献程度。研究发现中国林木剩余物的可用性达到了 1.52 亿吨,在各种类型的林木剩余物中,森林抚育间伐林木剩余物最多(87.46%)。在森林抚育间伐剩余物的各个子类别中,灌木平茬剩余物储量最高(6205万吨),占全国林木剩余物总量的40.79%。林木剩余物的分布具有显著的空间异质性,南方地区 13省提供了全国60.47%的林木剩余物,林木剩余物储量最大的三个省份是云南省(1438 万吨)、广西省(1209 万吨)和四川省(1050 万吨)。林木剩余物在前十年的分解速度较快,随后分解速度逐渐降低,全国林木剩余物分解速率在第二年达到峰值。林木剩余物百年累积碳排放量达到 5911.04 万吨。由林木剩余物自然分解导致的气候变化贡献值已达到 4927 万吨CO2 eq.各省气候变化贡献值从云南的 48.24 万吨 CO2 eq到宁夏的 7.5 万吨CO2 eq不等。因此,这部分分解导致的碳排放不容忽视,林木剩余物的能源化利用对森林资源管理和实现碳中和目标具有重要意义。
In the context of energy shortages and climate change caused by fossil fuels,an increasing number of countries are encouraging the use of forest residues as energy sources.However,due to data availability and limitations in research methods,it is challenging to quantify forest residues at a fine spatial scale.Therefore,studying the storage of forest residues and their contribution to climate change at the county level in China is of great significance.In this study,we developed a top-down model to estimate the storage of forest residues in China in 2018.Based on the decomposition process of forest residues,we quantified the carbon emissions resulting from their decomposition and assessed their contribution to climate change.The study found that China's available forest residue reached 152 million tons.Among various types of forest residues,silvicultural thinnings accounted for the largest proportion(87.46%).Within the subcategories of silvicultural thinnings,shrub clear-cutting residues had the highest storage volume(62.05 million tons),accounting for 40.79%of the total national forest residue.The distribution of forest residues exhibited significant spatial heterogeneity,with 13 provinces in southern China providing 60.47%of the national forest residue.The three provinces with the largest storage volumes were Yunnan(14.38 million tons),Guangxi(12.09 million tons),and Sichuan(10.50 million tons).Forest residue decomposition rates were relatively fast in the first decade and gradually slowed down thereafter,reaching a peak in the second year at a national level.The cumulative carbon emissions from forest residue decomposition over a century amounted to 59.11 million tons.The climate change contribution resulting from natural decomposition of forest residues has reached 49.27 million tons CO2 eq.The climate change contributions varied across provinces,ranging from 0.4824 million tons CO2 eq in Yunnan to 0.075 million tons CO2 eq in Ningxia.Therefore,the carbon emissions resulting from decomposition should not be overlooked,and the utilization of forest residues as an energy source is of great importance for forest resource management and achieving carbon neutrality goals.
刘伟国;田佳静;马泽萌;
生态预测与全球变化研究中心,西北农林科技大学林学院,杨陵 712100;生态预测与全球变化研究中心,西北农林科技大学林学院,杨陵 712100;生态预测与全球变化研究中心,西北农林科技大学林学院,杨陵 712100;
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