How can I explain to a non-native speaker that while this is correct:
The felling of trees.
And this is also correct:
This is not:
To a non-native it seems very reasonable that since many trees are being felled and given that the felling of trees uses the plural, the inverse form would also use the plural and become trees felling.
To a native speaker such as myself, the latter is very obviously wrong, but I couldn't figure out how to formalize this into a rule that a non-native can understand.