when should i prune a japaneese maple? live above atlanta ga(zone)?

Answer 1

I would be very thoughtful and careful in pruning a Japanese Maple. Every cut may represent years of growth because they grow so slowly. Before you start, think about what shape you want it to have when you are through, and work as though you were fixing minor flaws in a true work of art.
For health sake, slant every cut so that water will quickly drain away from the cut. Do not cut or saw into the "eyebrow" wrinkles which wrap around the top of the junction between trunk and branch. Make your cuts about 1/8 inch outside of those wrinkles, so that the cuts will heal over well.
It is going to be a mild winter in Atlanta, so I think you should prune right now, before spring comes. In spring your Maple will "bleed" alot, which in and of itself is not bad, but this sap flow will draw borers. Borers like Ambrosia Beetles can turn your tree into firewood before you even know it has been attacked. Borers are most active mid-spring, and your Maple should be on the mend by then.