What I am saying is I don't think the final scene with obj will represent the original scene with actual shader work. Reflections are not using texture coordinates from what I can see (looks the same with any patch size) so not the best gauge. When you apply PFs, or even images, with a 20 patch size the octaves of the PFs will be very low compares to the source PF, because of the UV normals from the patch size. And lowering the patch size dramatically increases render time.
Take a look at the OBJ rocks I was exporting, ill see if I can find a link. With patch size 20 there was almost no texture detail, bump, etc from the PFs for the default shader. I had to render with patch size 0.1 for 1m rocks. And said rocks end up being GB plus for a 1m obj. So that with a landscape... Yeah. Lol
I have done this a lot, for UE and stuff and the results are all garbage unless from a distance when fully textured.
I look forward to seeing your result.
PS trees are not a good example cause like I am trying to explain for a long time their normal/UV scale is much smaller, around the areas I am talking about, 0.1-1 in terms of patch size, which influences obj export. All these tests with just reflections don't mean much for normal/UV scale of the object for a scene standing in the mudpit with the characters in a foreground setting.