Reyn: The texture names in your Shape were missing the "treeWillow_" prefix so they weren't matching with the originals. I fixed that, and also added the "tsMaterialsMeshName" block to the GMND so that it can use the recolours of the original willow tree as well.
Thank you so much! I'll work from this to make sure I get the other trees right as well. Pulling original textures is always nice when you can manage it, for things like this.
Reyn Silversong-Sim Architect