Expansion of forest on land that, until then, was under a different land use, implies a transformation of land use from non-forest to forest. It includes afforestation which means the establishment of forest through planting and/or deliberate seeding on land and the natural expansion of forest through natural succession on land that, until then, was under a different land use.
FAO (2020) Global Forest Resources Assessment 2020: Main report. Rome. Available at: https://doi.org/10.4060/ca9825en.