Saturday, September 17, 2016

‘Ghost Forests’ Appear As Rising Seas Kill Trees

By John Upton
Sept. 15, 2016

OCEAN COUNTY, N.J. — Jennifer Walker stepped off her kayak into a wall of riverside grass. She steadied herself and stooped to scoop soil into a jar, then disappeared into the thicket for more. Analysis of amoeba fossils in the researcher’s samples may help to explain why, jutting above the head-high marsh grass a couple hundred feet further back, cedar forest was dead.

Bare trunks of dead coastal forests are being discovered up and down the mid-Atlantic coastline, killed by the advance of rising seas. The “ghost forests,” as scientists call them, offer eerie evidence of some of the world’s fastest rates of sea level rise.

Forests provide habitat and protect against global warming, but they’re declining worldwide because of land clearing, fires, disease and invasive species. The ghost forests show sea level rise can be yet another cause of deforestation.

Climate scientists like Walker, a PhD candidate at Rutgers University researching sea level rise, have begun investigating these dead forests, which are becoming common features along some coastal landscapes. The poison that kills the trees is salt, delivered to their roots by rising tides.


Seas are rising worldwide because of the warming effects of greenhouse gas pollution from fossil fuels and farms. Several feet of sea level rise is projected this century as the pace of climate change accelerates. That rise will inundate infrastructure, homes and ecosystems. Efforts to switch to clean energy, protect forests and revamp farming and transportation could curb the inundations ahead.

The mid-Atlantic is sinking faster than nearly anywhere else. The Gulf Stream has been shifting northward, bringing warmer water to the region, accelerating sea level rise. Meanwhile, groundwater pumping and natural geological processes are causing lands to sink.

High tides rose here by several inches during a recent decade. That was more than three times faster than the average rate of sea level rise worldwide, simulating conditions expected globally during decades to come.


Similar forest diebacks have been documented in Canada and Louisiana and monitored in wildlife refuges in Maryland. The botanical corpses occasionally topple during storms, becoming crisscrossed logs, which are slowly buried beneath the muck of marshes. Those marshes can migrate inland as seas rise.


Preliminary findings from an analysis by Virginia Institute of Marine Science (VIMS) scientists suggests 100,000 acres of coastal forest may have died off around the edges of the Chesapeake Bay since the 1850s. Much of the dead forest has now been replaced by marshland, while former marsh areas are now open water. Overall, the changes are diminishing the ability of plants in the region to fight global warming by absorbing carbon dioxide.


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