Forest Age Dataset of Southeast Tibet in 2019

This dataset provides a 30 m resolution spatially explicit map of forest stand age for southeastern Tibet (Tibetan Southeast) based on the reference year of 2019, covering three major forest types: evergreen broadleaf forest (EBF), deciduous broadleaf forest (DBF), and evergreen needleleaf forest (ENF). The dataset characterizes the age-class structure of natural forests in the region and supports analyses of vegetation carbon stocks and net primary productivity (NPP) attribution. Stand ages for other years can be derived by simple arithmetic on pixel values (e.g., adding 6 to each pixel yields 2025 stand ages).Dataset production used 2,126 forest inventory plots from Tibet's 2012 second-class forest resource survey and 2016 continuous forest inventory (EBF: 248; DBF: 34; ENF: 1,844), recording attributes including species composition, stand age, mean DBH, mean tree height, and geographic coordinates. The 2019 China 30 m canopy height product (GUO-LAB Digital Ecology Group) served as the spatial predictor. Forest type boundaries were delineated by masking with the 2020 classification layer from GLC_FCS30—1985—2020. Using mean tree height as the independent variable and stand age as the dependent variable, four regression models (linear, logarithmic, power, and exponential) were fitted for each forest type, with two-thirds of plots used for training and one-third for validation. Model accuracy was evaluated by R², RMSE, and MAE. The logarithmic model performed best across all forest types (R²: 0.44–0.84; RMSE: 19.15–29.37 years; MAE: 13.66–24.10 years; all significant at p < 0.01), and was applied pixel-by-pixel to generate the final stand age raster.The results indicate a mean stand age of 98.86 ± 23.72 years across southeastern Tibetan forests, reflecting a pronounced aging structure. Following the Technical Regulations for Tibet Forest Resource Inventory, young forests (<40 years), middle-aged forests (41–60 years), near-mature forests (61–80 years), mature forests (81–120 years), and over-mature forests (>120 years) account for 1.96%, 4.21%, 13.85%, 63.04%, and 16.94% of the total forested area, respectively. Mature and over-mature forests dominate all three types, comprising 76.02%, 61.70%, and 83.16% of EBF, DBF, and ENF areas. Data are stored in GeoTIFF format with pixel values in units of years, readable by ArcGIS, QGIS, or Python (rasterio library).