Iran’s ancient Hyrcanian forests on fire | Science

The Hyrcanian forests, located along the southern coast of the Caspian Sea, represent one of the world’s most valuable relic temperate ecosystems (1). Inscribed as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage site in 2019, this 1.85-million-ha ecosystem is home to more than 3200 plant species, 180 bird species, and dozens of mammal species (2). After surviving for more than 25 million years, the forests have lost more than half their original area since the 1950s, primarily as a result of land use change for agriculture and urban development (3, 4). In November 2025, late and inadequate firefighting efforts allowed a wildfire to destroy another 600 ha of the forests (5, 6).