Land-use dynamics influence estimates of carbon sequestration potential in tropical second-growth forest
Land-use dynamics influence estimates of carbon sequestration potential in tropical second-growth forest
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DOI：
10.1088/1748-9326/aa708b
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发表时间：
2017-07
影响因子：
6.7
通讯作者：
N. Schwartz;M. Uriarte;R. DeFries;V. Gutierrez-Velez;M. Pinedo-Vasquez
中科院分区：
文献类型：
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作者：
N. Schwartz;M. Uriarte;R. DeFries;V. Gutierrez-Velez;M. Pinedo-Vasquez
许多国家根据《巴黎气候协定》作出了通过重新造林固碳的重大承诺，最近的研究表明，热带次生林具有大量固碳的潜力。然而，次生林的碳收益受到非永久性的威胁，即清除或干扰将碳释放到大气中。次生林的好处需要在景观上长期存在，但对碳潜力的估计很少考虑次生林景观的时空动态。在这项研究中，我们使用来自秘鲁亚马逊地区景观的遥感图像来研究28年（1985-2013年）来第二次生长森林再生和持久性的模式。到2013年，研究地区44%的森林覆盖是第二次生长，超过50%的第二次生长森林像素不到5年。我们模拟了森林再生和清除的概率作为景观因子的函数。相邻森林的数量和与像素位置（即到边缘的距离）相关的变量对于预测清除和再生长都很重要。森林年龄是最强的预测清除概率，并建议清除概率年龄的阈值响应。最后，我们模拟了未来的碳封存轨迹使用我们的模型的参数。我们将其与二次生长持久性假设下积累的生物量进行了比较。估计数相差90万吨，相当于秘鲁在《巴黎协定》下通过“社区再造林”实现碳固存承诺的80%以上。虽然研究区域有超过4万公顷的次生林，但只有一小部分可能积累大量的碳。相反，森林和非森林之间的循环是常见的。我们的研究结果说明了在评估次生林固碳潜力时考虑景观动态的重要性。
Many countries have made major commitments to carbon sequestration through reforestation under the Paris Climate Agreement, and recent studies have illustrated the potential for large amounts of carbon sequestration in tropical second-growth forests. However, carbon gains in second-growth forests are threatened by non-permanence, i.e. release of carbon into the atmosphere from clearing or disturbance. The benefits of second-growth forests require long-term persistence on the landscape, but estimates of carbon potential rarely consider the spatio-temporal landscape dynamics of second-growth forests. In this study, we used remotely sensed imagery from a landscape in the Peruvian Amazon to examine patterns of second-growth forest regrowth and permanence over 28 years (1985–2013). By 2013, 44% of all forest cover in the study area was second growth and more than 50% of second-growth forest pixels were less than 5 years old. We modeled probabilities of forest regrowth and clearing as a function of landscape factors. The amount of neighboring forest and variables related to pixel position (i.e. distance to edge) were important for predicting both clearing and regrowth. Forest age was the strongest predictor of clearing probability and suggests a threshold response of clearing probability to age. Finally, we simulated future trajectories of carbon sequestration using the parameters from our models. We compared this with the amount of biomass that would accumulate under the assumption of second-growth permanence. Estimates differed by 900 000 tonnes, equivalent to over 80% of Peru’s commitment to carbon sequestration through ‘community reforestation’ under the Paris Agreement. Though the study area has more than 40 000 hectares of second-growth forest, only a small proportion is likely to accumulate significant carbon. Instead, cycles between forest and non-forest are common. Our results illustrate the importance of considering landscape dynamics when assessing the carbon sequestration potential of second-growth forests.