Pan-European forest stand age estimates using field-based and earth observation data

Forest stand age is a key variable in modeling carbon storage and uptake in forest ecosystems. However, consistently estimating stand age across Europe remains challenging due to labor-intensive field measurements and heterogeneous estimation methods. In addition, the availability and coverage of stand age field data vary widely across countries, with some lacking data entirely. Here, we present a spatially explicit forest stand age dataset for 2010 across Europe at multiple spatial resolutions. For regions with field data, stand age was estimated by integrating national forest inventory data with satellite-based disturbance information. For regions without field data, we used machine-learning models combining climate variables, satellite-derived tree height, and other Earth observation metrics to generate continent-wide stand age estimates. The resulting datasets provide the spatial distribution of forest stand age across Europe at 0.5° resolution for continental-scale analyses and ~ 1 km² resolution for regional applications, including associated uncertainty estimates, highlighting regions where old-growth forests are more likely to persist. By leveraging one of the largest compilations of forest field observations together with Earth observation data, our approach substantially reduces uncertainty relative to previous spatially explicit stand-age products, enabling their use in ecosystem modeling, biodiversity conservation, and climate adaptation planning across multiple scales.

Funding acknowledgement:
CLIMB-FOREST Horizon Europe project (No. 101059888), European Union.