I learned from Tom Wessels that multi-trunk trees, like this one, result from the resprouting of a hardwood stump. The diameter of the original stump can be estimated by finding the center-points of the current trunks, and taking these points to mark the perimeter of the old stump. The original tree here, then, must have been a hardy old basswood tree -- nearly three feet in diameter -- before it was felled. Location is at the west end of Wadsworth park near Route 157, not far from where the Coginchaug first enters into Middletown from Middlefield.

Here's some bark detail (this time from a tree just above the big waterfall):