June 22, 2014

Sandstone barrens' story one of fire and ice

Just north of the Blue Line that surrounds the mountains and rivers of the Adirondack Park, there is a cluster of special “islands” that makes up an ecological community only known in 20 locations in the world.

From the air and the ground these broad, flat expanses of sandstone pavement stand out from the surrounding mosaic of forest and fields.

The story of the sandstone barrens is one of ice and fire.

About 12,000 years ago, an ice dam broke as a glacier that extended all the way from Canada to Long Island melted. Enough water to fill Lake Ontario three times flooded forcefully across northern Clinton County, south through what is now the Champlain Valley, all the way down the Hudson River to the Atlantic Ocean.

The historic flooding scoured the area that is now northern Clinton County down to the bedrock that lay beneath the surface, exposing an underlying layer of bare, flat sandstone. 

In the few thousand years that followed, an array of plants colonized the sandstone pavement, creating a rare and fascinating natural community.

Gadway Barrens is a 520-acre preserve in Mooers about three miles south of the Canadian border.

This week I visited the barrens with retired SUNY Plattsburgh Professor Ken Adams, the staff of The Nature Conservancy Adirondack Chapter and other invited guests.

The most important lesson from Gadway is the role of fire in the health of this special ecological community.

The predominant tree is Jack pine. Jack pine is a boreal species of short trees that live up to 150 years. The barrens in Clinton County are the southern extreme of their range.

Their strategy for survival is to hold their seeds in tightly sealed cones that require high air temperatures — like those caused by fire — to melt the resin in the cones enough to release the seeds.

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