Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, 20740, USA.
Biospheric Sciences Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA.
Sci Rep. 2021 Apr 12;11(1):7919. doi: 10.1038/s41598-021-86944-2.
Trees outside forests (TOF) are an underrepresented resource in forest poor nations. As a result of their frequent omission from national forest resource assessments and a lack of readily available very-high-resolution remotely sensed imagery, TOF status and characterization has until now, been unknown. Here, we assess the capacity of openly available 10 m ESA Sentinel constellation satellite imagery for mapping TOF extent at the national level in Bangladesh. In addition, we estimate canopy height for TOF using a TanDEM-X DEM. We map 2,233,578 ha of TOF in Bangladesh with a mean canopy height of 7.3 m. We map 31 and 53% more TOF than existing estimates of TOF and forest, respectively. We find TOF in Bangladesh is nationally fragmented as a consequence of agricultural activity, yet is capable of maintaining connectedness between remaining stands. Now, TOF accounting is feasible at the national scale using readily available datasets, enabling the mainstream inclusion of TOF in national forest resource assessments for other countries.
森林外树木(TOF)在森林资源匮乏的国家是一种代表性不足的资源。由于它们经常被排除在国家森林资源评估之外,并且缺乏现成的高分辨率遥感图像,因此直到现在,TOF 的状况和特征仍不得而知。在这里,我们评估了公开可用的 10 米 ESA 哨兵星座卫星图像在孟加拉国国家级别的 TOF 范围测绘的能力。此外,我们还使用 TanDEM-X 数字高程模型估算了 TOF 的树冠高度。我们在孟加拉国测绘了 2233578 公顷的 TOF,平均树冠高度为 7.3 米。我们测绘到的 TOF 比现有 TOF 和森林的估计值分别多 31%和 53%。我们发现,由于农业活动,孟加拉国的 TOF 在全国范围内呈碎片化分布,但仍能够保持剩余林分之间的连通性。现在,使用现成的数据集可以在国家范围内进行 TOF 核算,从而使其他国家能够将 TOF 纳入国家森林资源评估的主流。