I tried out overgrown before, it had the same LOD issue as Vurts. I prefer Vurts tree models to Overgrowns though. I'm using a semi merged version of the two, using overgrowns grass with vurts trees, It's a pretty nice combo. May need to darken the grass texture a bit, but overall pretty nice.
On another note I found the file causing the 2D tree LOD issue with vurts. The file is called treedeadlod.dds, located in textures/landscape/trees.
I also deleted the entire textures/landscape/LOD folder Chuck mentioned.
