Combining Multiband SAR and InSAR for Mapping Forest Height

Remote Sensing has been widely used for monitoring forests, namely for the retrieval of structural parameters as the Forest Height (FH). The reason behind the use of remote sensing is the fact that measuring the FH through field campaigns is expensive and non-scalable. The resort to Airborne Laser Scanning campaigns, despite its high accuracy, have the same limitations. Therefore, Synthetic Aperture Radar (SAR) sensors carried by spaceborne platforms are widely used to address this problem. The aim of this paper is to assess the effects of combining multiband backscatter datasets (L and C bands) with Interferometric SAR (InSAR) variables (Coherence and Phase) for FH mapping resorting to a locally calibrated regression methodology. To make it more suitable for operational scenarios, only free access data is used, and the calibration sets are small. The scope of this study are the Mediterranean forests, and it has achieved a R²/RMSE ranging from 42.78-65.61%/1.68-2.68m in the validation and 47.23-64.38%/0.90-2.56m for the operational scenarios. The addition of the InSAR variables leads to an improvement of 3.44% in the R² and 0.07m in the RMSE.