Is it permissible to eat from the fruits of a tree planted in a public place, without permission?

So long as this tree is planted in a public place, and its planter is unknown, and the official responsible for that government department has not taken possession of it, then there is no harm for anyone to benefit from eating its fruit. However, one should not monopolize it; rather, people are equal in sharing it, and its fruit should not be left to spoil.