A frame around the subject gives it emphasis, makes it the center of attention. Usually the framing objects are in the foreground revealing the subject behind, but that can be reversed.
Explanation of Framing from Guidelines for Better Composision and Composition Refresher.
See how expert photgraphers portray Framing:
Pony Express School, Framing
Framing 1, Beginner
Framing 2, Beginner
Framing 2.5, Borders.
See also Windows and
Framing with Radial Balance. See more at Radial Balance.
Boy Scout Troop 174, Yorktown, NY. Scouting Photography Pages at http://troop174.info