Environmental site index for North America at 30 m (ESI v9 NA)

Environmental site index (ESI v9 NA): random forest predictions of site index (m, nominal base-age-50 scale of the unified FIA and Canadian compilation) from SoilGrids soils, Copernicus GLO-30 terrain, Hansen tree cover 2000 and a 1 km climate-based site index surface, on a 1 arcsecond grid (nominal 30 m) for the conterminous United States (masked to the US) and Canada (masked to Canada and to the area of applicability). Fit to 96,333 plot records (65,668 US FIA, 30,665 Canadian from Quebec, New Brunswick and Newfoundland and Labrador). Held-out skill (5-fold): US FIA plot-blocked R² 0.657 (slope 1.03) and 2° spatial-block R² 0.545; Canadian plot-blocked R² 0.108 (slope 0.705) and spatial-block R² −0.04. The Canadian surface fails its pre-specified skill gates and is released inside the area of applicability for inspection and testing, not as a validated product. Includes a 3 arcsecond per-tree ensemble spread (not a calibrated interval), the area of applicability at 0.009°, the 1 km ESI v6r predictor surface, model card, every cross-validation fold, border seam tests, verification reports and all scripts. This release repairs a Canadian DEM defect (667 missing Copernicus tiles had read as elevation 0). Fitted models and plot-level tables are withheld because training covariates were extracted at restricted true plot coordinates. See README.md for limitations, including an unaudited base-age harmonization.