Any way to export the tree and grass data of the terrain?

I need to downgrade the version from 2020.3 to 2018.4. Because the version gap is too large, I can’t directly use unitypackage to import assets, so I want to import them manually, but it seems that only the terrain can be exported in the form of textures. In the 2018.4 version after importing the map, the terrain does not carry trees and grass, and I can't find that export option. I tried to search for related issues, but I only found tutorials about drawing but no export.