I want to create a new forrest. But how?

1
Hallo.
I hosted a new Server with own Map. I hosted it over Feudal.Tools and setted the Tree Density to high.
And after this i addeted 8000 oaks with Quallity 80.
Now i see the Server got laggs all the Time becouse of Terrain Blocks.

After this i addeted a Tree Script. To delete all Trees under Quallity 40 and also stumps.

Then i started the Server. First Time it works and i got no laggs.

But then the Server has created all the deleted Trees new becouse of high Density.

I got a few Hours later the same Problems with laggs becouse of the Terrain Blocks.

Then i was thinking about how to fix that Problem and i found the Forest Maintenance XML Generator on Feudal.Tools.

I setted the general Setting into my Server. And uploaded the XML file.

But only thing is now i got a few less laggs but there are still tarrain blocks and i got laggs.

Can anybody help me please to fix this Problem ?