BY SIERRA RAINS-MOAD Staff Writer srmoad@oklahoman.comWhat was once an oak tree in an Oklahoma City resident's yard has transformed into a library filled with free books. Dave Summers said he and his girlfriend, Lindsay Fiegel, had shared their home for about four years when one of their oak trees caught on fire. The tree had been subject to a gas leak for about two years before, Summers said.Read more on NewsOK.com