I am currently using Lush Vanilla Trees SE with HQ Tree Bark and I love it. One thing missing though is the dead trees are untouched and in low resolution. So I check around the LE nexus and found 4K Parallax Treebark and Spooknik's - Tundra Trees HD. I combine these 2 mods and have great result. Both of the mods have open permissions so I guess I can share it on SE Nexus. Enjoy it if you too struggle to find HD models and textures for those trees.

This mod contains meshes and textures. Also include the aspen trees as bonus.
You can also use the original mod ports.

Compatibility
Lush Vanilla Trees SE - Compatible.
Skyrim Flora Overhaul SE - Should be compatible. Let this mod overwrites SFO.
Skyrim 3D Trees and Plants - The full version is probably incompatible but I am currently using the plants only version with no problems. There are 2 meshes conflict and I will let this mod overwrites for better consistency, but either way is fine.
Realistic Aspen Trees SE - Compatible patch provided.
SMIM  - Let this mod overwrites SMIM.
Bent Pines II - Let bent pines II overwrites this mod. Should be compatible now.

Credit
4K Parallax Treebark
Spooknik's - Tundra Trees HD