Composite Site Productivity Index (CSPI) v3.0.0: ESI v7 + Asym v9 + parent material overlay for the conterminous United States

Version 3.0.0 of the CSPI surface release. Extends the v2.0.0 multi-dimensional composite (ESI v7 + BGI + Asym + NPP, plus 3-component CSPI v2) with two new products motivated by the v0.10k manuscript analysis: (1) Asym v9 corrective surface at 30 m (forest-masked), refit on the v3 environmental predictor stack (SoilGrids 0-5 cm, SRTM terrain, Hansen tree cover) plus gSSURGO parent material category as a 10-class categorical predictor, OOB R^2 = 0.836 versus the v7 climate-only baseline of 0.828 (delta R^2 = +0.008, RMSE drop 8.40 to 8.21 Mg ha-1). (2) Parent material 30 m CONUS raster derived from gSSURGO copmgrp.pmgroupname grouped into 10 categories (Residuum, Alluvial, Marine, Glacial, Colluvium, Eolian, Other, Organic, Volcanic, Lacustrine), 1.4 billion pixels, 255 MB compressed, intended as a separately citable overlay layer for users who want to stratify their own productivity analyses by geology. Both products ship alongside the v2.0.0 baseline layers. The Asym delta layer (v9 - v7) is deferred to v3.0.1 to allow Zenodo deposit during the current session before the 90,000 x 212,400 pixel difference layer completes. The manuscript framing is that parent material acts as a cross-sectional stratification axis for ESI (height growth potential) and BGI (current biomass growth rate) but as a substantive predictive covariate for Asym (long-run carrying capacity), consistent with the ecological reading that deep substrate (rooting depth, bedrock chemistry, drainage class) influences carrying capacity more than short-run growth dynamics. v3.0.0 is the data release accompanying the manuscript Weiskittel 2026 (Forest Ecology and Management, in preparation). License CC-BY-4.0. See NEWS.md for the full v2.0.0 to v3.0.0 changelog and analyses/ for the underlying CSVs.