Advancing Forest Cover and Forest Cover Change Mapping for SDG 15: A Novel Approach Using Copernicus Data Products

Forests are the major component of the terrestrial ecosystem and provide an essential source of livelihood to local communities. Nevertheless, forests worldwide are increasingly threatened by natural and human-driven activities, such as extensive logging for the extractive industries, severe weather, pests and wildfires. A responsible forest management substantially contribute to the protection and conservation of forest ecosystem and services. The United Nations’ Sustainable Development Goals (UN SDGs) 15 “Life on land” – and specifically indicator 15.1.1 “Forest area as a proportion of total land area” – is concerned with mapping and protecting forest ecosystems.  At the European Union (EU) level, the UN indicator 15.1.1 is translated into EUROSTAT indicator “Share of forest area”.  Monitoring of this indicator enhance compliance with EU policies of land use and land cover, supporting the EU forest strategy for 2030 and helping to implement the regulation on deforestation-free products.

The SDGs-EYES project is a major EU-wide initiative aiming at exploiting data and information coming from the European Copernicus Programme to develop, implement and deploy a new service for monitoring SDG targets. It will provide novel and robust workflows to consistently assess SDG indicators across EU countries, with potential for global upscaling. In recent years, the release of frequent and high-resolution satellite data from the Copernicus Sentinel missions has opened new frontiers for consistently mapping global forest cover.  Nevertheless, detecting small-scale forest disturbance - also known as forest degradation - remains a challenging task. Studies aiming at quantifying the carbon emissions and extent of forest degradation show that it affects land portions similar to, or even larger, than deforestation. It is clear that accurate forest cover maps are urgently needed to avoid underestimating the loss of forest habitats, thereby preventing further carbon emissions, land degradation and biodiversity decline.

In this study, we apply a cumulative sum change detection algorithm on Sentinel-1 and Sentinel-2 time-series data to estimate forest cover and forest cover change in the Olt River basin, Romania, for the 2020-2022 period. Romania hosts the largest share (218,000 ha) of the EU's temperate primary and old-growth forests, many of which have been logged, both legally and illegally, although officially under protection by national parks or Natura 2000 sites. Through the integration of multi-sensor information (e.g. Sentinel-1 and 2, ESA CCI WorldCover), the resulting maps are able to detect hotspots of forest cover change at 20 m resolution, while also providing exact timing of the disturbance events. The suggested approach, hosted on the SDGs-EYES platform, provides a scalable methodology that can be systematically used in other geographical areas and for selected periods of interest. In this way, we enhance monitoring and evaluation of indicator 15.1.1, in agreement with the UN and EU indicators while improving the current weaknesses of the two frameworks.