Abstract Temporal information on mangrove extent, age, structure and biomass provides an important contribution towards understanding the role of these ecosystems in terms of the services they provide (e.g., in relation to storage of carbon, conservation biodiversity), particularly given the diversity of influences of human activity and natural events and processes. Focusing on the Matang Mangrove Forest Reserve (MMFR) in Perak Province, Peninsular Malaysia, this study aimed to retrieve comprehensive information on the biophysical properties of mangroves from spaceborne optical and Synthetic Aperture Radar (SAR) to support better understanding of their dynamics in a managed setting. For the period 1988 to 2016 (29 years), forest age was estimated on at least an annual basis by combining time-series of Landsat-derived Normalised Difference Moisture Index (NDMI) and Japanese L-band Synthetic Aperture Radar (SAR) data. The NDMI was further used to retrieve canopy cover (%). Interferometric Shuttle Radar Topographic Mission (SRTM) X/C-band (2000), TanDEM-X-band (2010–2016) and stereo WorldView-2 stereo (2016) data were evaluated for their role in estimating canopy height (CH), from which above ground biomass (AGB, Mg ha−1) was derived using pre-established allometry. Whilst both L-band HH and HV data increased with AGB after about 8–10 years of growth, retrieval was compromised by mixed scattering from varying amounts of dead woody debris following clearing and wood material within regenerating forests, thinning of trees at ~15 and 20 years, and saturation of L-band SAR data after approximately 20 years of growth. Reference was made to stereo Phantom-3 DJI stereo imagery to support estimation of canopy cover (CC) and validation of satellite-derived CH. AGB estimates were compared with ground-based measurements. Using relationships with forest age, both CH and AGB were estimated for each date of Landsat or L-band SAR observation and the temporal trends in L-band SAR were shown to effectively track the sequences of clearing and regeneration. From these, four stages of the harvesting cycle were defined. The study provided new information on the biophysical properties and growth dynamics of mangrove forests in the MMFR, inputs for future monitoring activities, and methods for facilitating better characterisation and mapping of mangrove areas worldwide.

中文翻译：

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通过结合多源遥感数据实现红树林结构表征

摘要 关于红树林范围、年龄、结构和生物量的时间信息为理解这些生态系统在其提供的服务（例如，与碳储存、保护生物多样性有关）方面的作用做出了重要贡献，特别是考虑到影响的多样性人类活动和自然事件和过程。本研究以马来西亚半岛霹雳州的马当红树林保护区 (MMFR) 为重点，旨在从星载光学和合成孔径雷达 (SAR) 中检索有关红树林生物物理特性的综合信息，以支持更好地了解它们在受管理的环境中的动态。环境。1988 年至 2016 年（29 年）期间，通过结合 Landsat 衍生的归一化差异水分指数 (NDMI) 和日本 L 波段合成孔径雷达 (SAR) 数据的时间序列，至少每年估计森林年龄。NDMI 进一步用于检索树冠盖度 (%)。干涉测量航天飞机雷达地形任务 (SRTM) X/C 波段 (2000)、TanDEM-X 波段 (2010–2016) 和立体 WorldView-2 立体 (2016) 数据在估计冠层高度 (CH) 中的作用被评估，使用预先建立的异速生长法从中获得地上生物量（AGB，Mg ha-1）。虽然 L 波段 HH 和 HV 数据在大约 8-10 年的生长后随着 AGB 的增加而增加，但由于砍伐后不同数量的死木碎屑和再生森林中的木材、约 15 和20年，L 波段 SAR 数据经过大约 20 年的增长后饱和。参考立体 Phantom-3 DJI 立体图像以支持冠层覆盖 (CC) 估计和卫星衍生 CH 的验证。AGB 估计值与地面测量值进行了比较。利用与森林年龄的关系，估计每个 Landsat 或 L 波段 SAR 观测日期的 CH 和 AGB，并显示 L 波段 SAR 的时间趋势可有效跟踪清除和更新的序列。由此定义了收获周期的四个阶段。该研究提供了关于 MMFR 中红树林的生物物理特性和生长动态的新信息、未来监测活动的输入以及促进更好地表征和绘制全球红树林区域的方法。