THE PILOT OF THE CESSNA 180 FLOATPLANE STATED THAT HE MADE A POWER REDUCTION AFTER TAKEOFF FOR NOISE ABATEMENT REASONS, AFTER CLIMBING TO ABOUT 40 FEET. HE CONTINUED TO CLIMB TO ABOUT 50 FEET AFTER TURNING CROSSWIND. HE STATED THAT WHEN HE TURNED EAST (DOWNWIND) TO FLY THROUGH THE CHANNEL, HE ADDED FULL POWER, BUT THE AIRCRAFT CONTINUED TO SLIP TOWARDS THE RIGHT SIDE OF THE CHANNEL AND IT ENDED UP CRASHING INTO THE TREES ABOUT FIFTY FEET FROM SHORE.