if you are going with bitmaps only, then this means that trunk texture can´t be tiled anymore - if it´s done the regular way . I know some cheats, but usually you have to cheat different in each application ;-)
So it would be interesting to see, if they have a "global" solution. The only global solution I have seen so far is, to ensure that trunk and each branch is really unwrapped "on it´s own", then you can paint seamless - but not tileable. That on the other hand means, you need really high resolution for the bitmap, otherwise it looks blurry.
As I said, I know several methods to do so, but until know it has been manual work and often had to be adjusted for each application.