While I don't believe the accuracy of the preceding sign, it is featured here as an example of how not to form a plural.
Plural: One tree. Two trees.
Possessive: The branch of the tree. The tree's branch.
Another such sign is at the other end of their carpark and the apostrophe has been removed post-production, along with the quote marks.
There are technically a few syntactical errors in this triptych, but the one I am focussing on is the apostrophe in Arch's, which ought to be Arches.
Oh, all right then... the others are the spelling of Artificial; and the capitalisation of common nouns (more in another post).
Last but not least for this set is sandwiches. (Yes, they also capitalise common nouns; and ice cream as two words is standard.)