CFATD: The First High-Spatiotemporal-Resolution Mapping of Forest Aboveground Biomass in China from 1985 to 2023 (Part Ⅰ: 1985-1993)

The China Annual Forest Aboveground Biomass Time-Series Dataset (CFATD) is the first comprehensive, high-resolution annual dataset specifically developed for monitoring forest aboveground biomass (AGB) across China. Covering the period from 1985 to 2023, this dataset was generated using a combination of multi-source remote sensing data and deep learning techniques, including residual neural networks. CFATD provides 30-meter resolution annual AGB density (AGBD) estimates, enabling a detailed assessment of spatiotemporal biomass dynamics in China’s forests.

CFATD is publicly available on the Google Earth Engine (GEE) platform, with updates planned annually. The dataset can be accessed via the following link:
👉 https://code.earthengine.google.com/4f8ad8d32ddb84e826e941a95f31f9be

Users can explore both AGBD estimates and the corresponding uncertainty layers (available only via GEE), supporting in-depth analysis of forest biomass trends and dynamics. Please note that uncertainty estimates are not included in the Zenodo repository.

The unit of CFATD is megagrams per hectare (Mg/ha). This is a density value, already normalized per hectare, so no further conversion based on pixel area (900 m²) is required when interpreting per-pixel values. Each pixel represents the AGBD of the forest within that 30 m × 30 m grid cell. However, to compute total biomass or carbon stock, AGBD values should be multiplied by the corresponding forest area (e.g., pixel area × tree cover fraction), following the approach outlined in our related publication (Cai et al., essdd, 2025).

The tree cover dataset used in these calculations, the China Annual Tree Cover Dataset (CATCD), is available from our peer-reviewed article:
👉 https://doi.org/10.1016/j.isprsjprs.2024.08.001
This article provides both GEE access and offline download links for CATCD.

Important note: The dataset may contain a small number of unusually high AGB values in certain regions (e.g., >1500 Mg/ha), which may reflect outliers or model artifacts rather than actual forest conditions. While these values occur only in a very limited portion of the dataset, users are advised to apply appropriate filters or quality control procedures when conducting sensitive analyses. These issues will be addressed in future dataset updates.

Citation:
Cai, Y., Zhu, P., Li, X., Liu, X., Chen, Y., Shen, Q., Xu, X., Zhang, H., Nie, S., Wang, C., Wang, J., Li, B., Wu, C., and Zhuang, H.: Dynamics of China’s Forest Carbon Storage: The First 30 m Annual Aboveground Biomass Mapping from 1985 to 2023, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2025-96, in review, 2025.

For data-related inquiries, please contact:
Dr. Yaotong Cai (caiyt33@mail2.sysu.edu.cn)