As said, depending on the tree and the bullets, it is not only possible, but documented in the Smithsonian museum. Follow this link for an image of a large tree cut off by rifle fire during the battle for Spotsylvania Courthouse during the American Civil War. http://www.civilwar.si.edu/weapons_stump.html
It depends on what tree size.
It is more an issue of how much ammo and the size of the ammo then tree size, but yes you can cut a tree down by shooting it.
That is the National Shooting Sports Foundation. They promote shooting sports. Gun control attempts to prevent ownership of guns used in shooting sports. No gun= no shooting sports.
Artillery, other airplanes, trench gun fire were all effective in shooting down airplanes.
Very dangerous. What goes up WILL come down again.
A shooting iron is a gun.
for mowing down large numbers, the M-60. for accuracy and precision shooting, the AK.
The question can't be answered without knowing what type of shooting and what "gun" you mean (hand gun, long gun, centerfire, rimfire, muzzle loader, etc..)
The carbon will darken the sights and cut down on reflection/glare.
The question can't be answered as asked. How big/thick is the tree? What kind of tree? What caliber machine gun? What are the specifications of the cartridge being fired? Even with that information, it will be hard to answer.
by shooting it with a gun.
practice
Shooting solder at a special solder shooting range
Gun clubs, shooting ranges