A national-wide dataset of plot-level living tree biomass and carbon stocks in Chilean native forests

Abstract. Native forests are critical components of the global carbon cycle, yet spatially explicit, national-scale assessments of their aboveground biomass and carbon stocks remain scarce for many regions. Here, we present a harmonized, open-access dataset of a tree-level raw field dataset detailing DBH, height, and species for 59,408 living trees across 77 species derived from 2,024 field plots spanning approximately 2,800 km (30°–56° S). Using these tree-level data, we estimated plot-level aboveground biomass density (AGBd, Mg ha⁻¹) and aboveground carbon density (AGCd, MgC ha⁻¹) for Chilean native forests. Biomass was estimated using a curated set of species-specific allometric equations; for the 29 % of trees falling outside the calibration ranges of their assigned equations, a Boosted Regression Trees (BRT) model was used as a model-assisted estimation approach, and evaluated against held-out allometry-derived biomass (R² = 0.979, RMSE = 0.2 in log-space). Results are presented as plot-level estimates by the 12 nationally defined Chilean forest types, three Plant Functional Types (PFTs), three ecoregions, and forest stand development, enabling integration with both national reporting frameworks and global carbon monitoring systems. The Valdivian temperate and Magellanic subantarctic ecoregions store the highest carbon stocks, with primary forest AGBd means of 233–295 Mg ha⁻¹ and individual plot values reaching 803.1 Mg ha⁻¹ of biomass density and 394.7 MgC ha⁻¹ of carbon stock density. The resulting dataset provides a national-scale field-based reference for aboveground biomass and carbon density in Chilean native forests, supporting national carbon assessment, Nationally Determined Contributions (NDCs) under the Paris Agreement, remote-sensing calibration and validation, and long-term forest monitoring of forest carbon dynamics under ongoing climate change. The Plot-level estimates of living trees carbon stocks in Chilean native forests are publicly available in https://figshare.com/s/d0fbe20f243bad166846.