Removing trees

[Tomispev]

Hi,

When I play EB, gameplay on the campaign map is veeery slow. I changed back to the vanilla seas, but that only sped things up just a bit. Then I noticed the large amount of forests and trees on the map, compared to the vanilla where they're far less. So I thought of removing them. I found a topic about speeding up performance, where there was a description about removing the .cas files from the \EB\Data\TERRAIN\AERIAL_MAP\TREE_MODELS.
But now every time I load on to the campmap I get an error message for every .cas file missing (I just backed them up). And I'm pretty annoyed pressing enter like twenty times each loadup. The game works smoothly without the trees btw.
So, how do I remove the trees without removing the .cas files? What file do I need to edit?

Thanks in advance,
TomiSpev