C-GGQL, a Far West Helicopters Bell 206B, was departing with two passengers on board off a helipad at an elevation of about 2500 feet ASL, 4 nautical miles north of Port Renfrew, BC. During the vertical ascent to rise above tree height, the torque gauge was indicating about 90-95%. Upon reaching an estimated 100-150 feet, the rotor RPM (Nr) was down to about 97%. The pilot reduced the collective slightly in an attempt to recover to 100% Nr. When the RPM did not recover, the ascent was stopped (at tree top height, approximately 200-250 feet) and the pilot immediately initiated a descent back towards the helipad. Almost immediately, the rotor RPM had decreased to 90% Nr and the low rotor RPM caution light and horn activated. The landing was hard, the left skid wedged under a helipad log and tilted backward. The main rotor blades struck the ground as the throttle was being rolled off and the helicopter came to rest on its right side. The occupants were not injured and evacuated unassisted.