On November 15, 2010, about 1330 Pacific standard time, an MD Helicopters 369D, N155PH, collided with terrain during an off airport landing near Salem, Oregon. Precision Helicopters, Inc., was operating the helicopter under the provisions of 14 Code of Federal Regulations (CFR) Part 137. The commercial pilot sustained serious injuries. The helicopter sustained substantial damage to the airframe and rotor blades. The local external load flight departed Newburg, Oregon, at an undetermined time. Visual meteorological conditions prevailed, and no flight plan had been filed.The pilot reported that he was transporting 500- to 900-pound bundles of Christmas trees on a 25-foot longline. He started flying at 0700; he flew 1 hour fuel cycles, and had been flying 6.5 hours. He had just placed a bundle of trees on the truck, and went to pick up another load. He located the ground personnel, and started his approach. About 100 yards out, he did a quick instrument scan, and noticed no anomalies. He looked back outside to set up for final approach to deliver the hook. Ground personnel did not indicate any problems with the hook or the helicopter. The pilot lowered the collective, applied a little aft cyclic to slow the helicopter, and applied right pedal to turn the helicopter, which allowed him the best possible view of the ground personnel. The pilot stated that just as he applied right pedal, the helicopter "banged hard," immediately started to shudder, and pitched forward violently with a left yaw. He lowered the collective, rolled the throttle to flight idle, and applied aft cyclic to level the helicopter. He set up for an autorotation landing; about 20 feet above the ground, he flared the helicopter to slow it and build inertia. He raised the collective to cushion the landing, and forward cyclic to attain a level attitude. The helicopter contacted the ground in a level attitude with slight forward speed. The pilot side landing gear collapsed. The pilot stated that at no time did he observe or feel the longline hook get hung or being dragged through the trees. Everything about the approach to the bundle seemed normal until he applied the right pedal. The pilot stated that the helicopter had a 100-hour inspection completed the previous night, and he had done a thorough preflight the morning of the accident. The weather was good with light wind, overcast sky, scattered showers, and temperature in the 40's. The pilot's door had been removed to aid visibility, and he was wearing a flight helmet with a clear visor, gloves, warm clothing, and rain gear. A Federal Aviation Administration (FAA) inspector examined the wreckage at the accident site. He retraced the path from the wreckage to the loading truck, where bundles of Christmas trees had been dropped off. There was a small hill that the pilot needed to fly over between the pickup point for the tree bundles, and where the trucks were being loaded. While walking along this assumed flight path, he found a portion of the longline cable and/or wire right beside a 7 - 9 foot Christmas tree. A section from the top of this tree was broken off. It appeared that the hook assembly had snagged the top of the tree. The tail rotor was found 20-30 feet away.