It would be nice to be able to make temporary signs by putting together several pieces of paper and writing on them in large letters. You could post a sign next to an egg tree you were trying to get the last egg from - Please do not pet or water before harvesting - or around a wood tree, to ask the opposite.
Signs could be taken down by deimaginators after a certain number of hours in game, and you might need to get a permit before being able to post your signs, having the language approved by the beaurocrocs.