Plantation in riverine sandbars offers an excellent opportunity for restoration of ecosystem with a vast potential for enhancing carbon stock. Afforestation on barren islands is challenging task; however, Padmashree Jadav Payeng has single-handedly transformed a sandbar of the river Brahmaputra into a forested landscape in India’s northeastern state of Assam. Such inspiring initiative needs more attention in terms of scientific assessment to quantify ecosystem value and services that can be enriched through such activities. This study uses remote sensing data viz., Landsat4–5TM and Sentinel 2 A data to provide a detailed information on spatio-temporal variability of land use land cover of study region from 1990 to 2021. It aims to conduct a scientific and systematic assessment of biophysical changes that have occurred in the sandbars, understand the status of afforestation, and evaluate the current levels of aboveground biomass (AGB), belowground biomass (BGB), and carbon stock in the selected sandbars. The spatial distribution of AGB, BGB and carbon stock is derived using linear regression model between SAR backscatter and field-based AGB. The results demonstrate that forest cover increased by 31.92 % and sandbar area is reduced by 26.87 % from 1990 to 2021. Spatially derived AGB ranges from 9 to 1295.89 Mg per ha, BGB from 2.35 to 290.50 Mg per ha and carbon stock from 6.18 to 763.34 Mg per ha. Ficus religiosa exhibits a high biomass, ranging from 564.7 Mg per ha to 994.7 Mg per ha, and a high carbon stock, ranging from 8 to 557.30 Mg per ha, attributed to its larger diameter at breast height (DBH). Moreover, phytosociological assessment was conducted for the studied forest, which reveal a total tree species richness of 79. The forest exhibits a total tree density of 395 individuals per hectare. Different biodiversity indices provide a comprehensive understanding of species composition; where results show a Shannon diversity index of 2.81, a Simpson's index of 0.08, a Menhinick's richness index of 2.7, and a Margalef's richness index of 5.26. The article provides detailed information on change in forest cover and present status of AGB, BGB and Carbon stock, providing evidence-based narratives on ecosystem restoration. The initiative by a single person has created a forested landscape and habitat for a large number of wild animals, contributing to better carbon stock and a healthier ecosystem. With regard to the current debate of carbon market, the study suggests the need of instrumentalization of carbon credits for such restoration activities to encourage increase in carbon stock. It also concludes that in-depth research should be taken up on long-term effectiveness of such plantation activities and the potential for scaling up these initiatives for ecosystem restoration in view of climate change mitigation and sustainable forest development.

中文翻译：

---

沙洲造林的潜在环境影响：来自印度阿萨姆邦布拉马普特拉河沙洲生态系统恢复计划的见解


在河流沙洲中种植为恢复生态系统提供了绝佳的机会，具有增加碳储量的巨大潜力。在贫瘠的岛屿上植树造林是一项具有挑战性的任务;然而，Padmashree Jadav Payeng 一手将布拉马普特拉河的一个沙洲变成了印度东北部阿萨姆邦的森林景观。这种鼓舞人心的举措需要在科学评估方面给予更多关注，以量化生态系统的价值和可以通过此类活动丰富提供的服务。本研究使用遥感数据，即 Landsat4–5TM 和 Sentinel 2 A 数据，提供了 1990 年至 2021 年研究区域土地利用土地覆盖时空变化的详细信息。它旨在对沙洲中发生的生物物理变化进行科学和系统的评估，了解植树造林的状况，并评估所选沙洲中地上生物量 （AGB）、地下生物量 （BGB） 和碳储量的当前水平。AGB 、 BGB 和碳储量的空间分布是使用 SAR 反向散射和基于场的 AGB 之间的线性回归模型得出的。结果表明，从 1990 年到 2021 年，森林覆盖率增加了 31.92 %，沙洲面积减少了 26.87 %。空间衍生的 AGB 范围为每公顷 9 至 1295.89 毫克，BGB 为每公顷 2.35 至 290.50 毫克，碳储量为每公顷 6.18 至 763.34 毫克。榕树的生物量很高，从每公顷 564.7 毫克到 994.7 毫克不等，碳储量高，从每公顷 8 毫克到 557.30 毫克不等，这归因于其胸高 （DBH） 的直径较大。此外，对所研究的森林进行了植物社会学评估，结果显示总树种丰富度为 79 种。 森林的总树木密度为每公顷 395 只。不同的生物多样性指数提供了对物种组成的全面理解;其中结果显示香农多样性指数为 2.81，辛普森指数为 0.08，门希尼克丰富度指数为 2.7，马格莱夫丰富度指数为 5.26。本文提供了有关森林覆盖变化以及 AGB、BGB 和碳储量现状的详细信息，提供了关于生态系统恢复的循证叙述。一个人的倡议为大量野生动物创造了森林景观和栖息地，有助于改善碳储量和更健康的生态系统。关于当前碳市场的争论，该研究表明，有必要将碳信用工具化，以促进碳储量的增加。报告还得出结论，应深入研究此类人工林活动的长期有效性，以及为缓解气候变化和可持续森林发展而扩大这些生态系统恢复举措的潜力。