Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100101, China.
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159817. doi: 10.1016/j.scitotenv.2022.159817. Epub 2022 Nov 2.
Dryland regions cover >40 % of the Earth's land surface. Both human activities and climate change have driven forest expansion in parts of dryland regions. Afforestation has been implemented widely to enhance carbon sequestration and benefit the ecological environment of many global drylands. However, the potential and available afforestation space in drylands is uncertain due to the conflicts between additional forest areas and available water. How afforestation will affect the potential for forest carbon stock is also unclear. This paper assessed the future spatial distribution of afforestation and potential forest carbon stock in a typical dryland region, the Yellow River Basin (YRB), which has experienced rapid afforestation and high human activity pressure over the past several decades. Combining the future land use change model (FLUS) and local important development planning, we simulated future afforestation distributions and estimated potential forest carbon stock under the ecological restoration, urban expansion, and cultivated land protection scenarios. The afforestation carbon stock was predicted by considering the dynamic change trends of the mature forest, the immature forest, and new afforestation. The results demonstrated that the potential afforestation area would be limited to 4000 km in the YRB accounting for less than one-twentieth of the total forest area. Accordingly, the maximum potential forest carbon stock would increase only 59.5 × 10 t. These findings implies that afforestation programs in drylands should further consider the optimum allocation of afforestation space and the balance between carbon and water in drylands, especially under a changing climate with increasing human activities.
旱地覆盖了地球陆地表面的>40%。人类活动和气候变化促使旱地部分地区的森林扩张。为了增强碳固存并造福许多全球旱地的生态环境，已经广泛实施了造林。然而，由于新增森林面积与可用水资源之间的冲突，旱地的潜在和可用造林空间是不确定的。造林将如何影响森林碳储量的潜力也不清楚。本文评估了典型旱地地区黄河流域（YRB）未来的造林空间分布和潜在森林碳储量，该地区在过去几十年经历了快速造林和高强度人类活动的压力。通过结合未来土地利用变化模型（FLUS）和当地重要发展规划，我们模拟了未来的造林分布，并在生态恢复、城市扩张和耕地保护情景下估算了潜在森林碳储量。造林碳储量的预测考虑了成熟林、幼林和新造林的动态变化趋势。结果表明，黄河流域的潜在造林面积将限制在 4000 公里以内，占总森林面积的不到二十分之一。相应地，最大的潜在森林碳储量将仅增加 59.5×10^6t。这些发现意味着旱地的造林计划应进一步考虑优化造林空间的分配以及旱地碳和水之间的平衡，特别是在气候变化和人类活动增加的情况下。
