TreeMap 2020, 2022, and 2023: Improved species range mapping in a tree-level forest dataset for the conterminous United States

Abstract. TreeMap is a tree-level model of the forests of the conterminous United States (CONUS) that provides a spatially continuous, 30 m resolution representation of forest structure and composition. It uses a random forests imputation approach to assign the most similar Forest Inventory and Analysis (FIA) plot to each forested pixel in gridded LANDFIRE data based on a suite of predictor variables that include vegetation, topographic, biophysical, and disturbance characteristics. By linking every mapped pixel to an FIA plot identifier for all forested areas in CONUS, TreeMap bridges localized inventory measurements with national-scale analyses and provides high-resolution estimates of forest structure and composition. In this update, TreeMap 2020, 2022, and 2023 incorporate climatic variables from Daymet in place of LANDFIRE biophysical variables. Further, we refined the independent validation by limiting the analysis to FIA plots where heterogeneity was administrative rather than ecological, excluding plots previously used to validate TreeMap versions that spanned heterogeneous forest conditions.  TreeMap 2020, 2022, and 2023 also implement a new process constraining the pool of FIA plots available for imputation within each LANDFIRE zone to species documented within that zone and its adjacent zones, thereby reducing implausible species assignments across CONUS. TreeMap 2020, 2022, and 2023 are publicly available at https://doi.org/10.2737/RDS-2025-0031 (Zimmer et al., 2025) and https://doi.org/10.2737/RDS-2025-0032 (Houtman et al., 2025), and https://doi.org/10.2737/RDS-2026-0038 (Zimmer et al., 2026), respectively.