Monthly Forest Canopy Cover Loss in Europe, 2017–2024

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The unprecedented droughts and heatwaves of 2018–2020 in Europe, often cascading with insect infestations, severe storms, wildfires, and intensified forest management, caused extensive forest disturbances. Remote sensing enables systematic mapping of such events. While tropical regions are covered by frequently updated disturbance products, Europe has so far relied mainly on annual maps. Recent studies have shown that national-scale mapping of temperate forest disturbances at weekly to monthly resolution is feasible using optical and radar data. Here, we present the first Europe-wide forest canopy cover loss (FCCL) product at monthly intervals and 10 m spatial resolution. We used all available Sentinel-2A/B and Landsat-8/9 Level-2 surface reflectance data (≤80 % cloud cover) from September 2017 to September 2024 to compute monthly composites of the Disturbance Index (DI) and its anomalies relative to the 2017 median. The DI integrates tasseled cap components and is normalized across forest areas. Deciduous and coniferous forests were processed separately to account for their distinct phenology, while remaining largely phenology-insensitive within each forest type. A fixed empirical threshold was applied to the DI anomalies to detect disturbances. Pixels exceeding the threshold for six consecutive months were classified as FCCL, minimizing false detections from transient canopy variations. We aggregated pixel-level results into equal-area hexagons and derived relative FCCL per forest type and region. Our results reveal distinct spatial and seasonal patterns of FCCL across Europe. Most losses—particularly those linked to forest management, such as regular harvest or salvage logging after bark beetle outbreaks—occurred in winter (November–April). In contrast, losses related to wildfire and drought were mainly detected in summer (May–October). Accordingly, the timing of maximum FCCL varies regionally: fire-prone areas, mostly in southern Europe, show summer peaks, while managed forests in Central and Northern Europe peak in winter. Locally, abrupt extreme events dominate seasonal dynamics. This study provides the first pan-European, monthly-scale assessment of forest canopy disturbances, capturing both winter and summer processes. Although detection in the far north is delayed during polar night, the temporal detail substantially improves over existing annual maps. The resulting dataset supports the timely classification of disturbance drivers and enhances Europe’s capacity for near-real-time forest monitoring and response.