I cannot ELY5 because I don't find that simple nor obvious and it would also require explaining the distinction of "unimproved" land value, but: "Ground-rents a

I cannot ELY5 because I don't find that simple nor obvious and it would also require explaining the distinction of "unimproved" land value, but: "Ground-rents are a still more proper subject of taxation than the rent of houses. A tax upon ground-rents would not raise the rents of houses. It would fall altogether upon the owner of the ground-rent, who acts always as a monopolist, and exacts the greatest rent which can be got for the use of his ground." - Adam Smith