The Warehouse defines the maximum amount of resources your city can produce. It also protects a certain amount of resources from being looted by your enemies. Note that basic resource production buildings in your city also increase the amount of protected resources. Note also that once the total amount of a resource reaches the warehouse limit, your city stops producing it. The only means to fill the warehouse further in this case would be harvesting resources on the Kingdom map or defeating other players!
Last Updated: 15d