After the acft landed, slush was observed to have accumulated under the wings & lower aft fuselage & was freezing. The acft was parked with the tail facing the sun, but none of the arpt personnel noticed whether the sun had melted the ice. The plt indicated he would return by 1630, but when the arpt manager was preparing to leave at 1715, the plt had not yet returned. Ice refroze on the rwy. The arpt manager notified the FSS & left a message on the phone answering machine that the arpt was closed. Also, to discourage operation on the icy rwy, he did not turn on the rwy lights. The plt returned at 1900 & elected to make a night departure. He reported that during takeoff, the acft lifted off, but would not continue climbing. Shortly thereafter, the acft collided with trees & the roof of a building, then crashed & burned. An exam of the wreckage revealed no evidence of a preimpact mechanical problem. Another plt noted a layer of frost on the leading edge of his acft's wings & elected not to fly. He believed that there was frost on N36791.