Tannersville Cranberry Bog

The Tannersville Cranberry Bog or Cranberry Swamp, is a sphagnum bog on the Cranberry Creek in Tannersville, Pennsylvania. It is the southernmost boreal bog east of the Mississippi River, containing many black spruce and tamarack trees at the southern limit of their ranges. Technically, it can be classed as an acid fen, as it receives some groundwater flow. The site was designated a National Natural Landmark in December 1974. It was purchased by The Nature Conservancy and the Conservation and Research Foundation in 1957. Like many bogs, its terrain presents an image of solidity, but a liquid mass of decaying peat lies beneath a six-inch (152 mm) layer of sphagnum and a network of supporting tree roots. However, this bog may be viewed from a floating walkway.HistoryThe bog began as a "kettle lake" formed approximately 10,000 years ago by a portion of the retreating Wisconsin Glacier (named according to geologic epoch, not location), which initially covered a depth up to the top of the current forest canopy. With restricted air and nutrient flow, sphagnum moss grew out into the lake, eventually forming a layer of peat over 40ft thick. While young bogs may contain an "eye" of open water where sphagnum has not yet reached, no such feature remains in the Tannersville Cranberry Bog. However, a narrow strip of open water marks the course of the Cranberry Creek, where the water is less acidic.