Ancient ozone holes may have sterilized forests 252 million years ago
Barren trees could have collapsed food webs, leading to Earth’s greatest mass extinction
![dwarf pines](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2018/02/020918_CG_pollen_feat.jpg?fit=860%2C460&ssl=1)
BARREN TREES Modern dwarf pines (shown) become unable to reproduce when irradiated by ultraviolet-B lamps. A similar fate may have befallen forests 252 million years ago, when massive bursts of volcanic gases likely weakened Earth’s ozone shield.
J. Benca