If you want to make a city or something, u can add realistic trees with this tutorial:
1. Put some BIZR anywhere on the screen
2. As it is falling, heat it
3. It forms a very realistic top to the tree
4. Make a trunk how ever you want (I recommend using wood or goo)
5. Done!

This a bonsai I made using the method:

LoadSaveBlock(76498);

Plz give credit if used

Try my method, and post the tree you make!

I use Bizr because it automatically forms the right shape. Using plant, u would have to go pixel by pixel to get the right shape.

P.S. When i say shape i am referring to how it has holes and its not just a solid blob