Investigators have not determined what caused a fire Friday night that destroyed most of the roof over the covered patio at McConnell Springs park off Manchester Street, park naturalist Laurie Thomas said.

Several wooden picnic tables on the patio also burned in the fire, which was reported about 11:30 p.m. Friday by a worker at a nearby business.

The adjoining visitors center was not damaged. The city park remains open, and no activities have been cancelled, officials said Wednesday.

An architect and a structural engineer have inspected the roof to determine how it can be fixed, Thomas said.

Beverly Fortune: (859) 231-3251. Twitter: @BFortune2010.