Jilly, if the model is already textured by whatever program its originated from, what you can do is pose it in Poser (if you have of course) and export as a bmp. In a Paint program, you can add or just leave the tree with a black background. In Vue, you can use this bmp file (jpeg, tiff etc...) on a plane. Not sure about Vue 2 but if its has a filter for alpha mask, you should do okay.