What would a specialized renderer be? I thought trees were going to be implemented in a traditional way, as in add 3D models with higher detail for what's really close and go reducing the quality after each LOD model to the point they become textures (which is what the engine does right now, right?).
That's it, the problem is only how one gets all the required LODs that will switch seamlessly and will be as efficient as possible.
Procedural tree generator is mainly about being able to generate vegetation geometry for the most efficient rendering, with all their LODs up to that billboard that we are currently using. But it's not just the generator that is meant to be procedural - it's also the rendering, which can make the individual trees varied in shapes, while they fall back into generic shapes with distance so they can switch to a lesser (and less varied) LOD there.
However, a procedural vegetation generator is a complex research project. This could be done in the traditional modeling way as well, to a degree ...
I could have sworn I saw something about using more traditional tree model's first, before eventually moving onto the 3rd procedural stuff.
... and that's why I wrote somewhere that we'll probably test that first. Might not be ideal with regards to performance and seamless transitions (lighting and geometry popping up), but faster to get some results.