Tree plantation expansion undermines natural forest protection by increasing fragmentation in China

China has expanded forest cover through the world’s largest afforestation initiative and the Natural Forest Protection Program (NFPP), yet national fragmentation trends remain uncertain because most assessments aggregate forest types. Here we map fragmentation dynamics of natural and planted forests across China (1990–2020) using composite structural and connectivity metrics. Planted forest fragmentation declined overall, whereas natural forest fragmentation increased across 60–64% of provinces