30-06 is a great round. However, if you are in search of a great brush gun, there is none better than the Marlin 45/70 Guide gun. Have you ever heard of a 405 grain bullet deflecting?
www.garrettcartridges.com has stories about people shooting through trees to harvest game, through trees. It will take anything, has incredible knockdown power, and it will not fragment because the bullets are cast or not expanding bullets, because .45 caliber has enough bore size to open a great wound channel without it. Keep the 06 for long shots, grab a marlin for everything else.