美国宇航局Tucker, Compton、Brandt, Martin和Hiernaux, Pierre带领其研究小组报道了非洲旱地单株树木次大陆尺度碳储量。2023年3月1日，国际知名学术期刊《自然》发表了这一成果。

该研究团队评估了来自30多万张卫星图像的99多亿棵树，覆盖了赤道以北半干旱的撒哈拉以南非洲地区。该课题组通过耦合现场数据、机器学习、卫星数据和高性能计算，将年降雨量在0 - 1000毫米的区域的每棵树的木材、树叶和根部的碳含量进行了归纳。单株的平均碳储量从干旱地区的0.54 Mg C ha^-1和63 kg C tree^-1到半湿润地区的3.7 Mg C ha^-1和98 kg tree^-1不等。

总的来说，研究人员估计他们研究区域的总碳为0.84(±19.8%)Pg C。与此前14个针对该区域流行的数值模拟研究比较发现，散生树木的密度和碳储量分别被3个模型低估和11个模型高估。这种基准测试可以帮助了解碳循环，解决土地退化的问题。该课题组人员为科学家、政策制定者、旱地恢复从业者和农民提供了每棵树的木材质量、树叶质量、根质量和碳储量的链接数据库，人们可以通过平板电脑或笔记本电脑估算农田树木的碳储量。

据悉，在次大陆到大陆尺度范围内，人们对旱地树木的分布及其密度、覆盖面、大小、质量和碳含量尚不清楚。这些信息对于旱地生态系统的生态保护、碳核算、气候减缓和恢复工作很重要。

附：英文原文

Title: Sub-continental-scale carbon stocks of individual trees in African drylands

Author: Tucker, Compton, Brandt, Martin, Hiernaux, Pierre, Kariryaa, Ankit, Rasmussen, Kjeld, Small, Jennifer, Igel, Christian, Reiner, Florian, Melocik, Katherine, Meyer, Jesse, Sinno, Scott, Romero, Eric, Glennie, Erin, Fitts, Yasmin, Morin, August, Pinzon, Jorge, McClain, Devin, Morin, Paul, Porter, Claire, Loeffler, Shane, Kergoat, Laurent, Issoufou, Bil-Assanou, Savadogo, Patrice, Wigneron, Jean-Pierre, Poulter, Benjamin, Ciais, Philippe, Kaufmann, Robert, Myneni, Ranga, Saatchi, Sassan, Fensholt, Rasmus

Issue&Volume: 2023-03-01

Abstract: The distribution of dryland trees and their density, cover, size, mass and carbon content are not well known at sub-continental to continental scales. This information is important for ecological protection, carbon accounting, climate mitigation and restoration efforts of dryland ecosystems. We assessed more than 9.9 billion trees derived from more than 300,000 satellite images, covering semi-arid sub-Saharan Africa north of the Equator. We attributed wood, foliage and root carbon to every tree in the 0–1,000mmyear1 rainfall zone by coupling field data, machine learning, satellite data and high-performance computing. Average carbon stocks of individual trees ranged from 0.54MgC ha^-1 and 63kg C tree^-1 in the arid zone to 3.7Mg C ha^-1 and 98kg tree^-1 in the sub-humid zone. Overall, we estimated the total carbon for our study area to be 0.84 (±19.8%)Pg C. Comparisons with 14 previous TRENDY numerical simulation studies for our area found that the density and carbon stocks of scattered trees have been underestimated by three models and overestimated by 11 models, respectively. This benchmarking can help understand the carbon cycle and address concerns about land degradation. We make available a linked database of wood mass, foliage mass, root mass and carbon stock of each tree for scientists, policymakers, dryland-restoration practitioners and farmers, who can use it to estimate farmland tree carbon stocks from tablets or laptops.

DOI: 10.1038/s41586-022-05653-6

Source: https://www.nature.com/articles/s41586-022-05653-6