Thursday, September 11, 2008

Beaver dam at the Z bridge on the Zealand Trail

This is the last dam in the current 'chain' of beaver dams and ponds that extend north through the Zealand valley. A photograph below shows this dam in the 1960's and it has been rebuilt one or two times since then by beavers. Also, it looks new in this photo but it's not. If you look carefully you can see that it is made from quite old material. It has impounded a large body of water for some time, though, as the beavers attempted, and for a time succeeded in controlling the flow of water through the valley for their purposes and it has, over time, dramatically increased the overall vitality of the valley, the fertility of the soil, the diveristy of plants and animals, and created a micro environment that is appealing to humans as well as native fauna and flora. Beaver dams and ponds are at best temporary although 'temporary' is loosely defined. From the photos we can measure some of the longevity of the Zealand Valley beaver dams, about 40-50 year at least, but we also know that eventually the ponds will become swamp-like, or bog-like and then, in their last stages become field-like, with grasses, sedges, and woody stemmed plants invading them as in the photo that follows.

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