ChinaTCC30: An annual 30 m tree canopy cover dataset for China from the 1970s to 2024 (Part 2: 1989-1994)

The China annual 30 m tree canopy cover dataset (ChinaTCC30) is a long-term, high-spatial-resolution dataset that maps tree canopy cover (TCC) across China from the 1970s to 2024. It was produced using an integrated framework that combines active learning, Random Forest modeling, and stand-growth-based historical backtracking to reconstruct TCC across China at 30 m resolution. The reliability and accuracy of ChinaTCC30 were rigorously evaluated using multi-source reference data and through comparisons with existing TCC products, yielding R-squared values of 0.66–0.83 and RMSE values of 14.68%–18.81%. The current release includes reconstructed historical TCC maps for 1975 and 1980, originally generated at 60 m native resolution and resampled to a 30 m grid for consistency with the annual products, as well as annual 30 m TCC maps for 1985–2024. For each year, the dataset is provided in GeoTIFF format and contains two separate raster files: a TCC raster and an Uncertainty raster, enabling users to select the appropriate data layer according to their research needs. Pixel values in the TCC raster range from 0 to 100, representing the percentage of TCC within each pixel. The Uncertainty raster characterizes the reliability of the estimated TCC values, with values defined as the standard deviation of five model predictions derived from five-fold cross-validation. ChinaTCC30 provides a valuable basis for characterizing the spatiotemporal patterns and dynamics of TCC across China. In addition to mapping annual TCC distribution, it can support raster-based statistical analyses and the application of user-defined canopy cover thresholds to delineate forest extent, thereby facilitating forest change detection, trend analysis, and broader ecological and environmental research. Note: This page presents Part 2 of the full ChinaTCC30 dataset and includes the TCC and Uncertainty maps for 1989–1994.