Ahah, I've tried looking myself, you will find it very difficult to find one, after hours of googling, I found no result, any I did find where extremely high poly, and exported with missing polygons. They had a Treemagik Plus which was free, but there is a download no where to be found of it as its not supported any more.
So what I did was look at how trees are made and tried it, my texturing skills let me down, but I know the technique for both the modelling at the texturing (even if mine did turn out crap) and I interpreted that into a tutorial:
Its done in Cinema 4D, but everything done is generic and can be done the same way in almost every 3D app, and the photoshopping can even be done in Paint.NET or GIMP. You should be able to shape it a lot better, but the tutorial is to teach the technique, considering I wrote it over a year a go
http://www.ozarkgames.com/smf/index.php?topic=528.0