I need a bit more information about this. So you've created a map. But did you use any meshes you've downloaded, did you export it correctly, did she put the files in the right area? Okay, so now the map is working. Well, what trees and caves are you talking about? The default ones from Feral Heart or downloaded ones? If it was downloaded meshes then make sure you haven't put them in a default object folder or it won't appear in game. Make a new object folder and save the mesh in there.
Maybe some screenshots would help me understand this more, too?