Chesapeake Bay, Virginia
Skeletal trees tower over the salt marsh, their bare arms outstretched like scarecrows. The salty sea wind polishes their chalky bones. The skeletons loiter like teenagers in the middle of the marsh – bored, out of place and suspicious. Trees, whether dead or alive, are not supposed to be in the grassy plains of the salt marsh unless elevated on a hill. Dead trees that appear in the middle of nowhere like fairy rings or Stonehenge hint at the supernatural; but these ghost forests are impeccably natural.
Throughout the Chesapeake ghost forests line the edge of salt marshes or sometimes rise up like specters in the middle of a marsh half a kilometer from the nearest forest. These are corpse-filled forests created by the sea where dead trees mean new life for the salt marsh.
Salt marshes chose real estate at the edge of the sea. And like any real estate at the ocean’s edge, it has to deal with not only flooding, but also a rising sea. A salt marsh has the same options as a house to deal with a rising sea: build vertically or move to higher ground. But the higher ground is often occupied by forests. A salt marsh wants to invade the forest and take over its land, but the tree is greedy and grabs sunlight by the armloads, leaving little energy for the forest floor. The salt marsh’s advantage is its ability to tolerate salty land and so it stays in the lowlands. In a rapidly rising sea, however, the salt marsh is caught between a woody devil and a not-so-deep-or-blue sea. One key to the marsh’s survival is patience and opportunity.
The sea has no politics. It does not care about borders and territory and competition between bickering ecosystems. As it rises, it slips past the forest boundary to bathe trunks and roots in brine. In time, trees will die, shedding their light-grubbing leaves, bathing the ground in solar energy. Awash in sunlight and without competition with tree roots, the salt marsh grasses march in and encircle woody trunks as bark flecks and falls away. Trees have always been stubborn and don’t easily give in to gravity or mortality and will stand tall over the marsh long after their phloem no longer flows, continuing to stake their claim even in the afterlife.
The movement of marshes into higher ground, especially into forests, is called marsh migration and is an important mechanism for salt marshes to escape a rising sea. Where a forest sees death, a marsh sees life. A salt marsh does not fear a ghost forest; it fears a hill, a seawall, a Food Lion parking lot, and a road – anything that prevents its escape against a rising sea.
Ghost forests can be found anywhere in the world where there are salt marshes, not just in the Chesapeake. There is a great post on saltmarsh migration by Joe Smith from New Jersey. There are also two great scientific publications on saltmarsh migration. One by Joe Smith and the other by Matt Kirwan at the Virginia Institute of Marine Science.