After you capture a piggy from a street, you can't take another piggy from that street for a week or so. (There is no such delay if you capture one in your back yard.)
How about the same delay for poisoning trees of any one type on any one street?
Right now, a small group of players with deep pockets repeatedly poison trees of type X (typically wood or spice) on the few streets where other glitchen expect to find an X-tree resource.
With the proposed code change, players who like to poison trees could continue to poison trees to their hearts' content. What they could not do is repeatedly frustrate a very much larger number of other players.
Furthermore, this rule would allow for some rough democracy. If players in general don't want X-trees on Street Y then the number of people poisoning X-trees will be large enough to overcome the desire of other players to keep X-trees alive and harvestable on a small number of publicly-known and reliably-findable streets.