# Forest monitoring with satellite data Satellite data detects forest damage and deforestation by comparing images of the same forest over time. Optical satellites such as Sentinel-2 show when the canopy changes or disappears, and radar satellites see through clouds and register clearings in the tropics. The cause of the damage, and the state of single trees, still need a check on the ground. ## How it works Forests change slowly in some places and suddenly in others. Satellites observe the same stands at regular intervals, so both kinds of change become visible. Because forests are large and often remote, EUSPA describes Earth observation and satellite positioning as increasingly important tools for forestry. Earth observation assesses forest health from a distance and detects illegal logging and deforestation [1]. Three kinds of signal matter: ### Forest extent and density The Copernicus Land Monitoring Service maps tree cover density for Europe every year at 10 m, from Sentinel-1 and Sentinel-2 data [3]. Comparing years shows where forest cover has thinned or gone. ### Forest health Infested trees change the way they reflect light. A study of spruce forests in the Czech Republic found that seasonal changes of Sentinel-2 vegetation indices, especially those built on shortwave infrared bands, can detect bark beetle infestation at the early green-attack stage [5]. ### Clearings and disturbance Radar signals pass through clouds. In the cloud-covered tropics, Sentinel-1 therefore provides gap-free observations every 6 to 12 days at 10 m, which allows near real-time alerts for small clearings such as selective logging [6]. **Figure:** Illustrative map, not real data. Woodland on the upper slopes, with the areas felled or damaged since the previous image. On the ground, satellite positioning guides forest machines and drones and locates sensors fitted to trees [1]. ## Which data and satellites | Question | Data | Example | | ------------------------------------------------------------------ | ------------------------------------------ | ----------------------------------- | | Where is forest, and how dense is it? | Yearly tree cover density | Copernicus Tree Cover Density, 10 m | | Are stands under stress? | Optical time series and vegetation indices | Copernicus Sentinel-2 | | Where has forest been cleared, also under cloud? | Radar time series | Copernicus Sentinel-1 | | How do forests change, and what is their role in the carbon cycle? | P-band radar | ESA Biomass mission | The ESA Biomass mission, launched on 29 April 2025, carries the first P-band radar in space. It measures the state of the world's forests and how they change, to improve knowledge of their role in the carbon cycle [7]. **Deforestation-free supply chains.** The EU Deforestation Regulation (EUDR) defines products as deforestation-free when the commodities were produced on land that was not deforested after 31 December 2020. It requires the geolocation of the plots of land, and it names Earth observation data, such as from Copernicus, among the means for checks [8]. An amendment of December 2025 applies the main obligations from 30 December 2026, and from 30 June 2027 for micro and small operators established by 31 December 2024. Micro and small primary operators may give the postal address of the plots instead of their geolocation, provided the address clearly corresponds to their location [9]. EUSPA describes how authorities can use GNSS coordinates of plots together with deforestation analysis from Earth observation [2]. This page describes the technology; it is not advice on the regulation. ## What you get - **Forest cover and density maps** for your area, year by year [3]. - **Alerts for new clearings or disturbance**, with location and date, also in regions with frequent cloud [6]. - **Maps of stands with stress signals**, so that forest management can act early and slow an outbreak [5]. - **Indications of possible illegal logging and deforestation** in large or remote forests, to direct checks on the ground [1]. ## Limits **Limits** - **Detail ends at the forest stand:** Sentinel-2 observes at the scale of forest stands and does not allow the detection of individual trees \[5]. - **Small clearings:** The Sentinel-1 alert system for the Congo Basin reliably detects disturbances of 0.2 ha or more; smaller events are not included \[6]. Other systems have their own minimum size, so ask for it. - **Damage is confirmed on site:** In the bark beetle study, the early-detection method reached 78% overall accuracy against field observations \[5]. A satellite signal tells foresters where to look; the cause and the extent of the damage are confirmed on site. ## How we help Forest monitoring services range from free Copernicus layers and openly published alerts [6] to dedicated services. Which one fits depends on your area, the size of change you need to see and how quickly you need to know. In a [strategy engagement](https://leto.space/consulting/strategy/) we define these needs with you, and we then write the requirements for choosing a provider. [More on requirements and procurement](https://leto.space/consulting/procurement/) To see who offers such services, use [Spacegraph](https://leto.space/spacegraph/), our discovery platform. Its marketplace has a use-case category for forestry management. ## Related use cases - [Monitoring habitats and water quality](https://leto.space/use-cases/habitat-water-quality/): Land cover in protected sites and the state of lakes. - [Monitoring the ESG impact of investment portfolios](https://leto.space/use-cases/esg-portfolio-monitoring/): Environmental indicators for assets in a portfolio. - [Analysing satellite imagery with AI](https://leto.space/use-cases/ai-imagery-analysis/): How models find clearings and changes across large areas. ## Frequently asked questions ### Which satellite data shows forest damage, and how often is it updated? For Europe, the Copernicus Land Monitoring Service publishes a yearly tree cover density layer at 10 m, derived from Sentinel-1 and Sentinel-2 [3]. For damage during the season, Sentinel-2 passes over the same place every five days with two satellites [4]. In the cloud-covered tropics, Sentinel-1 radar provides gap-free observations every 6 to 12 days [6]. ### Can satellites detect bark beetle infestation early? A 2021 study by Bárta, Lukeš and Homolová shows that they can give an early signal at the level of forest stands. In spruce monocultures in the Czech Republic, it used Sentinel-2 time series, especially indices from the shortwave infrared, to separate healthy stands from stands in the early green-attack stage, with 78% overall accuracy against field observations. Sentinel-2 does not allow the detection of individual trees [5]. ### How do we start a pilot for forest monitoring? Start with one area and one question, for example which stands to inspect first after a dry summer, or whether clearings appear in a supply region. Then check which forest inventory and boundary data you already hold. ## Sources 1. [EU Space Market Report 2026, Issue 1, EU Agency for the Space Programme (EUSPA), 2026-05-26](https://www.euspa.europa.eu/sites/default/files/documents/EU_Space_Market_Report_2026.pdf) 2. [EUSPA EO and GNSS Market Report, Issue 2, 2024, EU Agency for the Space Programme (EUSPA), 2024](https://www.euspa.europa.eu/sites/default/files/external/publications/euspa_market_report_2024.pdf) 3. [Tree Cover Density 2018-present (raster 10 m), Europe, yearly, Copernicus Land Monitoring Service, accessed 2026-10-06](https://land.copernicus.eu/en/products/high-resolution-layer-forests-and-tree-cover/tree-cover-density-2018-present-raster-10-m-europe-yearly) 4. [Sentinel-2 mission, European Space Agency (ESA), SentiWiki, accessed 2026-10-06](https://sentiwiki.copernicus.eu/web/s2-mission) 5. [Early detection of bark beetle infestation in Norway spruce forests of Central Europe using Sentinel-2 (Bárta, Lukeš and Homolová, International Journal of Applied Earth Observation and Geoinformation 100, 102335), International Journal of Applied Earth Observation and Geoinformation, 2021-08](https://doi.org/10.1016/j.jag.2021.102335) 6. [Forest disturbance alerts for the Congo Basin using Sentinel-1 (Reiche et al., Environmental Research Letters 16, 024005), Environmental Research Letters, 2021-01-19](https://doi.org/10.1088/1748-9326/abd0a8) 7. [Biomass (mission page), European Space Agency (ESA), accessed 2026-10-06](https://www.esa.int/Applications/Observing_the_Earth/FutureEO/Biomass) 8. [Regulation (EU) 2023/1115 of 31 May 2023 on the making available on the Union market and the export from the Union of certain commodities and products associated with deforestation and forest degradation (EUDR), European Union, EUR-Lex, 2023-06-09](https://eur-lex.europa.eu/eli/reg/2023/1115/oj/eng) 9. [Regulation (EU) 2025/2650 of 19 December 2025 amending Regulation (EU) 2023/1115 as regards certain obligations of operators and traders, European Union, EUR-Lex, 2025-12-19](https://eur-lex.europa.eu/eli/reg/2025/2650/oj/eng) Page: