The airline transport pilot was departing from an off airport site on a flight to his home airport under Title 14, CFR Part 91. The pilot reported that just after liftoff, a wind shift caused the tailwheel-equipped airplane to descend uncontrolled, striking its tail and left main landing gear on the ground. He said the airplane became airborne again, and he flew it back to the airport. He reported that once airborne, he saw that the left main landing gear was damaged by the impact with the ground. An examination of the airplane by the National Transportation Safety Board investigator-in-charge, showed substantial damage to the left horizontal stabilizer and the left main landing gear fuselage attachment.