A Comparison of Mangrove Canopy Height Using Multiple Independent Measurements from Land, Air, and Space

Abstract

Canopy height is one of the strongest predictors of biomass and carbon in forested ecosystems. Additionally, mangrove ecosystems represent one of the most concentrated carbon reservoirs that are rapidly degrading as a result of deforestation, development, and hydrologic manipulation. Therefore, the accuracy of Canopy Height Models (CHM) over mangrove forest can provide crucial information for monitoring and verification protocols. We compared four CHMs derived from independent remotely sensed imagery and identified potential errors and bias between measurement types. CHMs were derived from three spaceborne datasets; Very-High Resolution (VHR) stereophotogrammetry, TerraSAR-X add-on for Digital Elevation Measurement, and Shuttle Radar Topography Mission (TanDEM-X), and lidar data which was acquired from an airborne platform. Each dataset exhibited different error characteristics that were related to spatial resolution, sensitivities of the sensors, and reference frames. Canopies over 10 m were accurately predicted by all CHMs while the distributions of canopy height were best predicted by the VHR CHM. Depending on the guidelines and strategies needed for monitoring and verification activities, coarse resolution CHMs could be used to track canopy height at regional and global scales with finer resolution imagery used to validate and monitor critical areas undergoing rapid changes.

Improved assessment of mangrove forests in Sundarbans East Wildlife Sanctuary using WorldView 2 and TanDEM‐X high resolution imagery

“…; Lagomasino et al. ; Persson and Perko ). Despite, the coarser resolution canopy height that was estimated in the current study, it can still be useful in biomass and carbon assessments when coupled with field data (Shapiro et al.…”

“…; Lagomasino et al. ). WV2 imagery was comprised of eight multispectral bands that cover wavelengths between 430 and 1050 nm.…”

“…For the land cover classification of mangrove species in SEWS, we used two types of Earth observation: (1) passive sensor high resolution (2 m spatial resolution) from WV2 and (2) active sensor for example, TDX Synthetic Aperture Radar (SAR) images (12 m spatial resolution). The WV2 imagery provided multispectral information about land cover types, while the TDX imagery was used to produce accurate canopy height models for mangrove forests Lagomasino et al 2016). WV2 imagery was comprised of eight multispectral bands that cover wavelengths between 430 and 1050 nm.…”

“…Considering these setbacks, remote sensing has played an important role in augmenting field inventories, by increasing the spatial and temporal mapping of mangrove areas (See Kamal and Phinn 2011;Viennois et al 2016;Shapiro et al, 2015;Stringer et al 2015). Over the last few decades, both multispectral and radar imagery have been used in mapping regional and global mangrove coverage, measuring mangrove communities and structure at the local scale, and estimating other biophysical properties (Giri et al 2011;Heumann 2011;Kamal and Phinn 2011;Kuenzer et al 2011;Lagomasino et al 2016;Thomas et al 2017;Bunting et al 2018;Lee et al 2018).…”

“…Recent advances in the large-scale mapping of mangrove canopy height using interferometric synthetic aperture radar imagery can be a potential option to help improve mangrove species classification. Using these advanced techniques, mangrove canopy height has been estimated at a 12 m spatial resolution and an RMSE of less than 2 meters for expansive sites in Mozambique, Mexico and Bangladesh using TanDEM-X (TDX), a German Space Agency mission comprised of two satellites flying in formation Lagomasino et al 2016).…”