Like giant bones planted in the earth, clusters of tree trunks, stripped clean of bark, are appearing along the Chesapeake Bay on the United States’ mid-Atlantic coast. They are ghost forests: the haunting remains of what were once stands of cedar and pine. Since the late 19th century, an ever-widening swath of these trees have died along the shore. And they won’t be growing back.

These arboreal graveyards are showing up in places where the land slopes gently into the ocean and where salty water increasingly encroaches. Along the United States’ east coast, in pockets of the west coast and elsewhere, saltier soils have killed hundreds of thousands of acres of trees, leaving behind woody skeletons typically surrounded by marsh.

What happens next? That depends. As these dead forests transition, some will become marshes that maintain vital ecosystem services, such as buffering against storms and storing carbon. Others may become home to invasive plants or support no plant life at all — and the ecosystem services will be lost. Researchers are working to understand how this growing shift toward marshes and ghost forests will, on balance, affect coastal ecosystems.