This is a collection of pine tree models (three distinct types).
Redwood pine, cypress pine, himalayan cedar.
These are not made with Unity tree creator. They are made in 3ds max.
To place the trees on terrain, you can use the wonderful free plugin, "mobile foliage shader" by Frost.

Each tree model has three LOD versions. The final version being a very low poly billboard.
Each tree uses one material (leaves / trunks are all on the same texture).

Polycounts for the trees range from 2,000 --> 4,000
The LOD1 for each tree reduce the polygons by half, and LOD2 is a simple billboard with about 60 polygons