The private certificated pilot took off from a lake in the float-equipped airplane ferrying supplies and a passenger from a hunting camp under Title 14, CFR Part 91. The pilot reported that the airplane was slow to come up on step due to heavy chop, and described the winds as gusting to 30 knots. He said the airplane became airborne and then settled back into the water. The airplane lifted off the water again, and began to climb slowly. The pilot said the airplane climbed to about 100 feet above ground level as it crossed the shore, and then began to descend. He said the engine was at full power, and he lowered the nose to gain airspeed, but the airplane continued to descend. He said he maneuvered around some large trees before the airplane struck smaller trees, and settled onto the tundra. The float supports collapsed and right wing struck the ground. In a written statement, the pilot wrote that he should have departed with a lighter load, or waited for better weather. He also wrote that he should have re-evaluated the conditions after the airplane settled into the water following the first liftoff.