Old houses may not be haunted, but they retain many palpable vestiges of their pasts. And when Margot Anne Kelley and her husband, Rob, moved into an old farmhouse, they inherited that past as well as the property. On their one acre on Maine's mid-coast, they learned much about the history of their home not by visiting the local historical society but by spending time observing the trees, plants, and grasses that had been planted by those who once...