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Conservation Commission

Conservation and More

              by Bruce B. Beckley

Issue #126, September, 2002
Sweet Rocks & Walking Ferns

Larry Newcomb worked so others could know the wild plants as he knew and loved them. He wasn’t a forceful teacher. He would lay out a buffet of learning opportunities, most notably his wildflower guide, for the learner to draw upon. One of those subtle teaching creations was the Fern Trail at Moose Hill Wildlife Sanctuary. That trail wandered through a dry, typical unadorned stretch of oak woods. Larry created pockets along the trail to suit each fern’s chemistry; here a dry rocky niche, then a basin of humus inside a poly-lined hole designed to trap rainwater. And so it went, a place in which each fern species could survive and look natural in a suburban woodlot.

Larry’s efforts came to mind as we walked around Bartholomew’s Cobble in Ashley Falls, Massachusetts. A national botanical treasure, the cobble rising 100 feet beside the Housatonic River is an ancient formation of limestone and marble laced with quartzite. In New England, other definitions aside, “cobble” can refer to a large rock formation standing above the valley floor. Bartholomew’s Cobble was already half a billion years old when it was pushed up from the earth’s ancient depths 500 million years ago as a younger tectonic plate shoved under the older rock. This was back when today’s African continent was jammed against New England.

Depth upon depth of ocean silts buried the cobble until erosion carried them away and polar ice caps lowered the sea levels. Then, seemingly only yesterday in geologic time, the cobble was buried again this time by the glacial till of Lake Sheffield. These sands and boulders, too, were carried away on the Housatonic’s rushing melt waters. Now, a much more placid Housatonic which meanders from oxbow to oxbow, hardly knowing which way it’s to flow, continues the process of change in its daily rubbing against the cobble’s feet.

Above the cobble magnificent ramrod straight pines and hemlocks three feet and more in diameter create a canopy that shades the rock. During our visit, warm humid air was blowing from the cornfields across the river, creating enough condensation on the cool quartzite so the mosses and plant roots were close to dripping.

Millennia after millennia of acidic precipitation have dissolved away the marble exposed on the cobble’s surface leaving the quartzite pock marked. In these pockets, like those Larry created along another trail, many, many plant and fern species have found home sweet home in a habitat sweetened by the dissolving marble and limestone. Over 500 vascular plants including 50 fern species have been identified on the 329-acre reservation. The small walking fern with the looks of a common leafy plant is one of these. It reaches out from one of the solution pockets to the length of its 4-inch long frond to touch the moist earth. At that point the frond may send out roots and start a new plant on its walk.

Bartholomew’s Cobble is a fascinating place deserving of the protection given by the Trustees of Reservations. Likewise, although much more common (as are the ACC properties) the Moose Hill Wildlife Sanctuary deserves the protection given by the Massachusetts Audubon Society. As you travel, find these protected places and thank the protectors for their foresight and efforts.

Nearby

Stratham voters approved a $5 million bond issue to permanently protect 750 acres, roughly one-third of the town’s remaining buildable land, to preserve rural character, conserve wildlife habitat and protect groundwater. The voters recognized the ill effects of sprawl in their small rural town and acted.

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