The background was far harder to get right then each Goblin was. In fact, the Goblins were easy compared to the background. I had an idea of what I wanted in my head, but getting there took a lot of experimenting. I redid just about every aspect at least once, the tree trunks took about 4 tries to get to the stage I wanted them. First they where too tall and thin. I finally got the shape, size and texture right.
The foliage also took a lot to figure out. At one point the foliage and trunks were blending into each other. So I thought, lets darken the top of the trunks as if being shaded by the leaves, which lead to the thought of dappled light. That took a bit to get right. Eventually it all feel together.
I really learned a lot working on this, the background in particular. I had thought to try and do something different, like putting them inside a cave, as that would be easier, but I stuck with my idea, until I worked out a solution I was happy with.