Dense forest : Individual or cluster foliage?

here, I want to make a large and dense forest, performance-wise, is it better to have individual trees and bushes models, or clusters?
Since it’s a dense forest, I’ll have a LOT of foliage instances, and I’m concern about the hit that would have the occlusion and the LOD computations.

The way I’m seeing this forest is with a lot of plants and bushes covering the ground, and quite large trees with overgrowth vegetation gwrowing on it, that would eventually occlude a large part of what would be visible in front of us; the manner a tropical virgin forest would be.

If any of you have already worked on a forest world, I’ll be glad to know how you manage it?