全球森林及林产品碳科学研究进展与前瞻

Advances and frontiers in global forest and harvested wood products carbon science

森林和木质林产品是全球碳循环系统中的一个重要组成部分,能够对大气层温室气体的浓度造成重大影响。研究发现全球森林在最近几十年平均每年从大气中吸收二、三十亿吨碳,而毁林和森林退化又造成每年10多亿吨的碳排放。全球森林碳汇并不平衡,由于森林面积的增加,美国、加拿大、中国、欧盟等国家和地区的森林碳汇在近几十年里有了巨大的增长,而在南美洲、中美洲、非洲、南亚和东南亚,毁林却造成了森林碳汇大量减少。相对于森林碳汇来说,木质林产品碳储量较小,但在全球尺度上木质林产品碳储的持续增加对减排的贡献却非常重要。近10年的研究发现,使用木质林产品替代高能耗非林产品可以对林业整体的减排效益做出重要贡献,而生命周期分析法的引入使得这种替代减排效应的核算更为准确。主流研究强调使用集成评估,将经营森林和源于这些森林的木质林产品看作一个整体,从而把两者的碳储及碳排放系统结合,集成评估能够更全面准确地核算整体林业的净温室气体效应。林业碳科学的研究前沿在以下重要领域仍需着力拓展:充分考虑气候变化对森林生长及森林碳汇的影响;积极推进并完善各国的森林资源清单;可持续管理和优化使用森林资源以使林业在减缓气候变化方面的贡献最大化;构建和完善林产品生命周期数据库;加强全球林业减排效应的集成评估和系统研究。

Forests and harvested wood products（ HWP） is an important part of the global carbon cycle,and can significantly affect the greenhouse gas（ GHG） concentration in the atmosphere. Thus,in the last few decades,forest carbon science has become a hot research area world wild. Initial research efforts mostly focused on forest carbon stocks and stock changes,which indicated that in the last a few decades,the global forests have been a large and consistent carbon sink,absorbing 20-30 million tonnes of carbon from the atmosphere each year while also releasing more than 10 million tonnes of carbon through deforestation and forest degradation. The global forest carbon balance appeared differently： in countries such as the United States,Canada,China,and countries from the European Union,afforestation and reforestation have resulted in increased total forest areas and thus increased forest carbon stocks. But deforestation in South and Central America,Africa,and South and Southeast Asia has caused significant reduction in the total forest areas and forest carbon stocks. The second research focus has been HWP carbon dynamics. At a global scale,HWP carbon stocks are much smaller when compared with forest carbon stocks. But consistent HWP carbon stock increases can have important implications on the mitigation potential of the forestry sector（ managed forests and HWP produced from these forests）.Based on life-cycle analysis,studies conducted in the last 10 years have concluded that substituting HWP with energyintensive materials can result in significant emission reductions. To accurately assess net GHG effects of the forestry sector,it is essential to integrate forest carbon dynamics with life-cycle analysis of HWP carbon stocks/emissions. There are a few important issues that need to be addressed in the future：（1） Collect more data and conduct data-based studies tobetter analyze climate change impacts on forest development and forest carbon stocks,and reduce analysis uncertainty.（2） Develop,complete,and improve forest resources inventories,the basis for accurately assessing forest carbon stocks.（3） Develop strategies through sustainable forest management and the best use of wood biomass resources to maximize forestry sector＇s mitigation contribution within key emission reduction timeframes.（4） Collect and integrate HWP life-cycle data in a systematic way to improve the accuracy of HWP life-cycle analysis and wood substitution assessment.（5） Assesse global forestry sector＇s mitigation contribution by integrating forest management and HWP carbon stocks/emissions analysis at a global scale.