Fig. 1

Global extent of forest area and worldwide case studies on microplastics in soils. The global land area covered by forests with a tree canopy hight > 5 m was 40.2 million km² in 2020. Global forest cover distribution includes large contiguous forest areas in all climate zones. Worldwide, case studies conducted on microplastics in soils between 2016 and 2022 have a clear focus in Europe and eastern China. More than 75% of microplastic case studies have been conducted on arable lands, including on croplands, grasslands and plasticulture. Research indicating the presence of MNPs in forests have included studies on forest air, water and tree leaves. Global land cover data from Frontiers | The Global 2000–2020 Land Cover and Land Use Change Dataset Derived From the Landsat Archive: First Results (frontiersin.org), global forest cover data from Tree cover (2000) | Global Forest Watch Open Data Portal and global microplastic case study data from Weber and Bigalke (2022) [28]