Hello, I am an illustrator living in Portland, OR with experience working on fantasy trading cards, mobile games, and videogames. I wanted to see if my work might be of interest to you and below is a link to my portfolio site.
I'm very interested in your idea, but i'm not sure about your offer... how much for every piece, around 90-100$ per campaign piece? or for all the images?... If you want to pay that price, for (i dont know) ten pieces, you must sacrifice a lot of quality.
I might be able to help. I generally work in a 'semi-realistic' style with more of a painterly edge. If you're looking for trees with backdrops similar to the example you provided, I think I can fit the aesthetic. If needed, I can also provide you with examples outside of the work in my gallery that are more relevant to the graphic design skills needed to create the trees.