I know this particular area well, having flown past it dozens if not hundreds of times. It is covered with very dense, low scrubby trees. It looks to me like the pilot has landed vertically (either under power or in auto) on the tree tops and they have supported the weight of the helicopter as they have collapsed beneath it. I don't believe he has executed a perfect zero speed auto to a helicopter sized hole in the trees. I'm very skeptical about the helicopter autorotating from an overwater position all the way to the landing site. Depending on exactly where it occurred he would have been at a maximum altitude of 500' or 1000' in order to stay below the control zone step. The pilot said he had 30-35 seconds to land the aircraft, and also mentioned a loss of transmission. I'm guessing he flew under power back across the coast and maybe then entered auto. He seemed to choose his words very carefully and I don't believe he ever actually used the words "engine failure". Just my opinion of course and I'm certainly not having a go at the pilot.