The NASA’s Global Ecosystem Dynamics Investigation (GEDI) satellite mission aims at scanning forest ecosystems on a multi-temporal short-rotation basis. The GEDI data can validate and update statistics from nationwide airborne laser scanning (ALS). We present a case in the Northwest of Spain using GEDI statistics and nationwide ALS surveys to estimate forest dynamics in three fast-growing forest ecosystems comprising 211,346 ha. The objectives were: i) to analyze the potential of GEDI to detect disturbances, ii) to investigate uncertainty source regarding non-positive height increments from the 2015–2017 ALS data to the 2019 GEDI laser shots and iii) to estimate height growth using polygons from the Forest Map of Spain (FMS). A set of 258 National Forest Inventory plots were used to validate the observed height dynamics. The spatio-temporal assessment from ALS surveying to GEDI scanning allowed the large-scale detection of harvests. The mean annual height growths were 0.79 (SD = 0.63), 0.60 (SD = 0.42) and 0.94 (SD = 0.75) m for Pinus pinaster, Pinus radiata and Eucalyptus spp., respectively. The median annual values from the ALS-GEDI positive increments were close to NFI-based growth values computed for Pinus pinaster and Pinus radiata, respectively. The effect of edge border, spatial co-registration of GEDI shots and the influence of forest cover in the observed dynamics were important factors to considering when processing ALS data and GEDI shots. The use of GEDI laser data provides valuable insights for forest industry operations especially when accounting for fast changes. However, errors derived from positioning, ground finder and canopy structure can introduce uncertainty to understand the detected growth patterns as documented in this study. The analysis of forest growth using ALS and GEDI would benefit from the generalization of common rules and data processing schemes as the GEDI mission is increasingly being utilized in the forest remote sensing community.

中文翻译：

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利用GEDI激光雷达数据和机载激光扫描来评估快速生长物种的高度生长动态：西班牙的一个展示柜

美国国家航空航天局（NASA）的全球生态系统动力学调查（GEDI）卫星任务旨在在多时间短轮转的基础上扫描森林生态系统。GEDI数据可以验证和更新来自全国机载激光扫描（ALS）的统计信息。我们使用GEDI统计数据和全国ALS调查在西班牙西北部介绍了一个案例，以估算包括211,346公顷的三个快速增长的森林生态系统中的森林动态。目的是：i）分析GEDI探测干扰的潜力，ii）研究从2015-2017 ALS数据到2019 GEDI激光发射的非正高度增量的不确定性来源，以及iii）使用多边形估算高度增长来自西班牙的森林地图（FMS）。一组258个国家森林清单图用于验证观测到的高度动态。从ALS调查到GEDI扫描的时空评估可以大规模检测收成。樟子松，辐射松和桉树的年平均生长高度分别为0.79（SD = 0.63），0.60（SD = 0.42）和0.94（SD = 0.75）m。ALS-GEDI正增量的中位数年值分别接近针对松树松和辐射松计算的基于NFI的增长值。边缘边界的影响，GEDI镜头的空间共配准以及森林覆盖率对观测到的动态的影响是在处理ALS数据和GEDI镜头时要考虑的重要因素。GEDI激光数据的使用为林业行业的运营提供了宝贵的见解，尤其是考虑到快速变化时。但是，由于定位而产生的错误，地面发现者和树冠结构可能会引入不确定性，以了解本研究中记录的检测到的生长模式。随着GEDI任务越来越多地用于森林遥感界，使用ALS和GEDI进行森林生长分析将受益于通用规则和数据处理方案的概括。