Painting Trees is the first of our step by step tutorials for Jungle DVD and Painter. It provides an illustrated walk through of the tools and techniques necessary to paint tree textures for use in Bryce, Terragen or other 3D applications as well as 2D scenes.
The birch tree is actually a 512 pixel texture map that took about 10 minutes to paint. This image is from the rendered scene. The precision masking that distinguishes the tree comes from painting the tree as a layer. The shadow below is a texture too, but that's another tutorial.
The files below contain everything you'll need including a nozzle library, trunk portfolio, lighting and brush library. The PDF tutorial takes about 20 minutes. Just follow the steps and have fun.