Tree Optimization

I need to create a forest of a especific type of trees that i need to remove the branches because i am making a harvester simulator.

The tree creator doesnt allow me to remove the branches so i created my own tree , the tree is exactly as it is in unity but when i make a big number of them its slowind down in a way that the tree creator`s trees doesnt.

What should i do?

I have not played around with the Terrain engine much so this is just an idea.

Use Unity’s trees and replace them with your trees when they need the branches removed. It might still slow your FPS down, but it shouldn’t be as much as it was when it was only your trees.

I need to cut every tree in the scene and i have 3 different models , wasnt it be too rough for the user to see the replacement?

I need to cut every tree in the scene and i have 3 different models , wasnt it be too rough for the user to see? the replacement?