This is very nice, but it definitely could be better. The very most important thing when laying out a forest is to identify your number one, two and three trees. These are usually your biggest, next biggest and third biggest tree.
The placement of these three trees is crucial to the development of the rest of the forest. Other trees can equal these, but none should be bigger.
Draw an imaginary cross in the container, centered length ways and front to back. Position number one tree to the left of center and either in front or back of the center. Position number two opposite of the number one, other side of pot and if number one is to the front then number two to the rear of center line. Number three is positioned as a support tree for number one, close, but opposite side of the center line.
Once you have these three trees positioned you can add in the rest of the trees around them keeping your smallest trees for the rear position.
I think you'll see a great improvement in your design and layout of your forests.