The best way to find out how to shoot thru trees and other handy tips and tricks is to get with me, I'll show how and why as well as how to!
The second best way is to watch for a tank on the other side of the trees. Shoot at him with your machine gun, move the gun back and fourth watching the hit sprites, some will hit the tank, ( between the trees) and some will hit the trees, once you've done that you will be able to see where to fire your round,,,, also, depending on the range,, your gun doesn't fire in the same exact line your sight sees, this is important when you are really close to the target.
I'm available for training Mondays wensdays and Fridays or anytime you see me in game,, just drop me a pm and we can go to the TA , there are Lots of tips and tricks to tanking and I'll be happy to show you all I know!