Wall‐to‐wall Amazon forest height mapping with Planet NICF, Aerial LiDAR, and a U‐Net regression model
| Authors: | Fabien H. Wagner, Ricardo Dalagnol, Griffin Carter, Mayumi C. M. Hirye, Shivraj Gill, Le Bienfaiteur Sagang Takougoum, Samuel Favrichon, Michael Keller, Jean P. H. B. Ometto, Lorena Alves, Cynthia Creze, Stephanie P. George-Chacon, Shuang Li, Zhihua Liu, Adugna Mullissa, Yan Yang, Erone G. Santos, Sarah R. Worden, Martin Brandt, Philippe Ciais, Stephen C. Hagen, Sassan Saatchi |
| Year: | 2025 |
| Type: | Scientific Journal |
| Station: | International Institute of Tropical Forestry |
| DOI: | https://doi.org/10.1002/rse2.70041 |
| Source: | Remote Sensing in Ecology and Conservation |
Abstract
Tree canopy height is a key indicator of forest biomass, productivity and structure, yet measuring it accurately at regional or larger scales, whether from the ground or remotely, remains challenging. The objective of this study is to generate the first complete canopy height map of the Amazon forest at 4.78m resolution using Planet NICFI imagery and deep learning. Specifically, we (i) trained a U-Net regression model with canopy height models (CHMs) derived from tropical airborne LiDAR and their corresponding Planet NICFI images to estimate canopy height, (ii) evaluated the accuracy of our map against existing global products based on Sentinel-2/1 and Maxar Vivid2 imagery and (iii) assessed its capacity to capture small-scale canopy height changes. Tree height predictions on the validation sample had a mean absolute error of 3.68 m, with minimal systematic bias across the full range of tree heights in the Amazon forest. The main biases are a slight overestimation (up to 5m) for heights of 5–15m and an underestimation for most trees above 50 m. Outperforming existing global model-based canopy height products in this region, the model accurately estimated canopy heights up to 40–50m with minimal saturation. We determined that the Amazon forest has an average canopy height of 22 m (standard deviation 5.3 m) and exhibits large-scale patterns, ranging from the tallest forests of the Guiana Shield to shorter forests along wetlands, rivers, rocky outcrops, savannas and high elevations. Events such as logging or deforestation could be detected from changes in tree height, and the results demonstrated a first success in monitoring the height of regenerating forests. Finally, the map of the Amazon forest canopy height is displayed.