There is a map error in that corner...try map copying a group of Gaia trees from a pristine area of the map, and fill the corner (area were it crashes) with only Gaia trees.
I believe the error is being caused by the mix. In that you have originally put down a tree terrain, and edited with Gaia.
If Gaia is desired there, try completely removing the 'terrain trees' and replace with a grass type.
Then insert Gaia.
I doubt there is an amount that will cause your game to crash, unless you are working from an older com.
I have hundreds of Gaia trees in Dragonfly, and the map is an 8 player.
Did you ever notice that when you place terrain trees and then delete some of the trees it will then not accept the same trees back in those places? In other words the game engine continues to recognize terrain trees even after they are deleted.
I think the map error occurs when a designer attempts to mix in 'Gaia Trees' with 'Terrain Trees.' So to work the other way around is best.
"I take it that this is the Anastasia Scud pines for?" - Epic Commander
"What Ana said. Use sugar and the whip." - aka the Pilot
"I think you will realize the emphasis was on Ana and Cake." - Monk