Abstract

Structural metrics from the NASA Global Ecosystem Dynamics Investigation (GEDI) are vital to support monitoring, restoration and protection of high biodiversity spots. The Chilean Patagonia is home of pristine and unique ecosystems where GEDI data can provide knowledge on structure and biomass and expand the current limitation in Patagonia on field measurements and open lidar data. Conservation efforts are ramping up across our study area in the Aysen Region. Ongoing and future conservation efforts precise from unbiased estimates of forest carbon stocks to value and to protect forest biodiversity. We evaluate GEDI structural metrics and biomass estimates in the evergreen forests of the Chilean Patagonia using National Forest Inventory (NFI) data and unmanned aerial vehicle (UAV) lidar mapping to assess aboveground biomass density (AGBD) across six conservation projects. Estimates from GEDI ranged between 186 and 255 Mg ha-1. Both AGBD distributions for NFI plots and the gridded map were similarly centered as both converged in the median value (100 Mg ha-1). However, the NFI gridded map turned asymptotic after 200 Mg ha-1, showing the lack of representation in the NFI sampling of dense high-C forests, whereas GEDI estimates were able to sense these areas of old-growth forests. The distribution of GEDI tracks, the scale extension of the projects and the available NFI information explained the differences between using GEDI samples and the NFIcalibrated solution using UAV-lidar. Our results showed the limitations of the Chilean NFI over steep locations and uplands where old-growth forests dominate, and where only GEDI can depict structural metrics and reliable estimates of ADGB and forest carbon. This study is highly relevant to support conservation projects in Patagonia using publicly available GEDI data science, and to enforce ambitious legislation in Chile designed to protect biodiversity and for which quantification, reporting and verification of forest carbon stocks is crucial.