This is tree bark which has been cut away. The city fathers try to discourage this because it wrecks the tree, but our guides told us it had medicinal value. It may be an intellectual property issue with the Swiss multinational that owns the genome of the tree, having bought it from the same guys who sold Manhattan, but I've done enough paragraphs on that. I think this is a Shea Tree, Butyrospermum parkii. The Shea Tree is valuable for its oil, called Shea Butter, and its suggestive Linnaean name. You can see why they wouldn't want you hacking the bark up.