On September 24, 2020, at 1624 Pacific daylight time, a Great Lakes 2T-AI-2, biplane, N3617L, was substantially damaged when it was involved in an accident near San Diego, California. The flight instructor sustained serious injuries and the pilot receiving instruction had minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that the airplane underwent a preflight and was fueled before the first flight of the day with the pilot receiving instruction. The pilot receiving instruction was on the flight controls for the takeoff and the airplane was climbing at 70-80 mph when he noticed a lack of climb about 350 ft above ground level. The flight instructor took control and started to troubleshoot by checking that the throttle, mixture, and propeller controls were full forward. The fuel shutoff valve was in the ON position. Due to obstructions straight ahead, he initiated a steep turn back to the runway and established a 75-mph glide. The flight instructor saw trees and tried to turn inside of them toward the runway while not departing controlled flight or getting too slow. The airplane subsequently collided with a tree and crashed in a parking lot outside of the airport perimeter. A video surveillance camera captured the airplane in a steep descent after the impact with the tree. A witness at the airport reported that he heard the engine sputtering and looked to see the airplane on takeoff, level off about 300 ft agl while making a right turn. The airplane slowed dramatically, and the nose of the airplane started going down. By the time the airplane had completed a 180o turn, the nose of the airplane was pitched down about 40o. The airplane recovered enough airspeed to bring the nose up when it hit a tree. The engine was partially torn from its mounting points and suffered significant impact damage. The exhaust system sustained crush damage, and the fuel servo broke away from the oil sump. The propeller had separated from the crankshaft, about 1 inch aft of the propeller flange. Both blades were intact and straight and did not exhibit evidence of chordwise scratches or leading-edge nicks. The fuel selector valve sustained impact damage and was found in the OFF position; however, fuel was found in the fuel lines and components downstream. The engine and electrically driven fuel pumps were intact. The crankshaft was rotated, and accessory gear and valve train continuity was established. All eight spark plugs were removed and displayed normal operating signatures. Magneto-to-engine timing was confirmed, and both magnetos sparked with the impulse coupling. A drill was used to rotate the magnetos to speed, and spark was produced on each remaining undamaged ignition lead. Examination of the engine and fuel servo revealed no anomalies.