Smith Pond Bog Sanctuary

About the Formation of the

Smith Pond Bog

Sanctuary

Return to the Smith Pond Bog Sanctuary

The Formation of Bogs

As mentioned previously, kettle hole ponds were first formed with the melting of ice blocks left from retreating glaciers. As the climate warmed in the glacier's wake, plants and animals, in order of their hardiness, reoccupied most of northern North America. These last arrivals were recorded in the standing water by the bog itself, which has preserved pollen in its layers of peat from plants of the spruce-fir forest and later mixed hardwood forest.

Unlike a swamp or marsh, a true bog is circled by higher ground and has no inflow or outflow of water. (ASNH's Ponemah Bog in Amherst is an example of a true bog.) Dead and partially decayed plant material build to enormous depths and eventually alter the development of the bog. The formation of typical bogs begins at the pond's edges with the growth of a floating mat of Sphagnum Moss, aquatic herbs and eventually certain shrubs and trees.

Because there are no inlets of fresh water, rainwater and runoff are the only source of nutrients into a bog, creating a strongly acidic, anaerobic (lacking oxygen), nutrient-poor environment. Because of these conditions, normal decay is extremely slow, causing organic plant remains to accumulate as peat. The accumulated organic matter releases humic acid into the water that, together with acidic glacial debris underlying most northern New England bogs (generally granite), increase the acidity of bog water. The absence of oxygen and the acidity of bogs are known to have distinct preserving qualities; the remains of 2,000 year old "bog people" have been discovered in the heaths and bogs of Europe.

This unique, acidic bog environment is highly suitable for certain hardy and specialized plants, some of which are relic species that, outside of bogs, are now largely confined to Arctic and Alpine areas.

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