How do I Fade Terrain Tree's to Blend with Billboard?

Hi.

I have a tree system that uses tree gameobjects rather than unity's built in system.

I developed a LOD/Billboard script to work with this tree system.

I'd like the tree game objects to fade out while the billboard fades in to avoid the popping effect.

I'm using nature/treeSoftOcclusion bark and leaves.

I tried fading out the materials alpha channel but it does not work with this shader.

I tried lerping from this material to a material that had a transparent/diffuse shader attached with an alpha channel of 0.0f but this resulted in the object reducing in size to nothing rather than fading its opacity to nothing.

I think that lerping between two materials with very different shaders is what caused the strange effect.

Does anyone have any ideas of a way to make this work? I'm running out of ideas.

[EDIT] I tried starting with the transparent/diffuse material with alpha channel 0.0f on the tree. Then lerping to the material with the nature/softOcclusionTreeLeaves. This sort of worked. It fade from nothing to a full tree, however the properties of the nature shader were not applied so the tree looked pretty bad.