And in Civ 4: - you can destroy roads (needed for some resources) - you can also occupy the tile or destroy the improvement (mine/plantation/camp/quarry/etc)

And in Civ 4: - you can destroy roads (needed for some resources) - you can also occupy the tile or destroy the improvement (mine/plantation/camp/quarry/etc) needed to harvest a resource - you can use diplomacy to deny a resource - you can use a spy to destroy an improvement