Woodworkers prefer it because they are lightweight effortless to cut stain and hit a nail into.
Frame out garage door.
If the door is 7 tall frame the opening 7 1 5.
If you are installing a 9 wide door the opening will be 9 3 wide.
Header the header is ideally a minimum 12 wide micro laminated beam that spans the width of the garage door opening.
Header requirement 2 at minimum the header should be 12 wide with doubled 2 4 at opening and ceiling running the width of the door with a 2 4 in the center of the opening for the center bracket to attach to.
Frame the rough opening to 3 inches wider than the garage door size you have selected.
Pine is an excellent choice for a garage door frame.