Below are screenshots of my progress of making the first setting. It is only in the animation for around 6 seconds and is the opening scene, where we first see the boy on his bike.
I began by modelling the path that is between the grass. I didn't quite know how to do it at first, and so I started by creating three spheres and then I tried to put them together, but it didn't like right and it didn't look like a hill, and would make it look like the boy would ride off an edge. I then decided to use a cylinder and make the path through edge loops and extruding. This looks a lot better and matches the animatic.
I then wanted to see how the trees would be positioned before going ahead and modelling them. I, therefore, placed an equal amount of cylinders either side of the path. Some of them had to be moved around a little, otherwise it would be hard to see the boy riding on the path.
I then used a cylinder and the edge loop tool to create the trees. I made them look very simple and almost christmas tree like. The trees still need a little more work, like the sharp point at the top, but I think they match the ones in the animatic and don't make the forest look like a scary place to be in.