The pilot, accompanied by a flight instructor, was conducting mountainous backcountry familiarization training. The flight instructor reported that they had taxied about 1,000 feet down the runway because the field was wet. During takeoff at a high altitude (6,370 feet elevation) backcountry airstrip, the pilot reported that the airplane became airborne near the end of the runway. During the initial climb, the flight instructor reported that the pilot pulled back on the yoke abruptly, which caused the nose of the airplane to pitch up and obstruct their forward view. The flight instructor further reported that he told the pilot to lower the nose of the airplane to build up airspeed and allow for a visual reference. As the pilot lowered the nose, the left wing of the airplane impacted a tree. The flight instructor reported that he and the pilot assessed the damage and controllability of the airplane, and decided to continue their flight since they did not want to do any more maneuvering than was necessary and they were already headed towards their destination airport. During cruise flight, the flight instructor noticed some "pulling" to the left and some visual damage to the left wing. The flight instructor further reported that they landed at their destination airport uneventfully. A postaccident examination revealed substantial damage to the left wing and aileron. The pilot reported there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. A postaccident mechanical inspection by the pilot's mechanic revealed a 20/80 compression on the No. 3 cylinder. A representative from the engine manufacturer stated that there would have been negligible power loss due to the low compression and that the postaccident compression test would be invalid because the test was conducted on a cold engine. Included in the public docket for this report is a copy of the service bulletin from Continental on the procedures for conducting a differential pressure test and borescope inspection procedures for cylinders.