Department of Earth and Planetary Sciences, Weizmann Institute of Science, Rehovot, Israel.
Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel.
Glob Chang Biol. 2020 Mar;26(3):1626-1637. doi: 10.1111/gcb.14927. Epub 2019 Dec 14.
The rate of change in atmospheric CO is significantly affected by the terrestrial carbon sink, but the size and spatial distribution of this sink, and the extent to which it can be enhanced to mitigate climate change are highly uncertain. We combined carbon stock (CS) and eddy covariance (EC) flux measurements that were collected over a period of 15 years (2001-2016) in a 55 year old 30 km pine forest growing at the semiarid timberline (with no irrigating or fertilization). The objective was to constrain estimates of the carbon (C) storage potential in forest plantations in such semiarid lands, which cover 18% of the global land area. The forest accumulated 145-160 g C m year over the study period based on the EC and CS approaches, with a mean value of 152.5 ± 30.1 g C m year indicating 20% uncertainty in carbon uptake estimates. Current total stocks are estimated at 7,943 ± 323 g C/m and 372 g N/m . Carbon accumulated mostly in the soil (71% and 29% for soil and standing biomass carbon, respectively) with long soil carbon turnover time (59 years). Regardless of unexpected disturbances beyond those already observed at the study site, the results support a considerable carbon sink potential in semiarid soils and forest plantations, and imply that afforestation of even 10% of semiarid land area under conditions similar to that of the study site, could sequester ~0.4 Pg C/year over several decades.
大气 CO 变化率受陆地碳汇显著影响，但该碳汇的规模和空间分布以及增强其以缓解气候变化的程度存在高度不确定性。我们结合了在一个 30 公里长的 55 年生针叶林中进行的碳储量 (CS) 和涡度协方差 (EC) 通量测量，该森林生长在半干旱的林线（无灌溉或施肥），测量时间为 15 年（2001-2016 年）。目的是限制对半干旱土地上森林人工林碳储存潜力的估计，这些土地覆盖了全球陆地面积的约 18%。根据 EC 和 CS 方法，该森林在研究期间积累了 145-160 g C m 年，平均值为 152.5±30.1 g C m 年，表明碳吸收估计存在 20%的不确定性。目前总储量估计为 7943±323 g C/m 和 372 g N/m 。碳主要积累在土壤中（土壤和立木材积碳分别约为 71%和 29%），土壤碳周转时间长（59 年）。尽管在研究地点已经观察到了预期之外的干扰，但结果支持半干旱土壤和森林人工林具有相当大的碳汇潜力，这意味着在类似于研究地点的条件下，对 10%的半干旱土地进行造林，可能会在几十年内封存约 0.4Pg C/年。
