You have a land card in hand, and are able to play a land this turn.
Steps
Play a land card from your hand.
The land enters the battlefield, triggering Tireless Provisioner, creating a Food or a Treasure token.
The Food or Treasure token enters the battlefield as a 1/1 Saproling artifact creature that is also a Forest land due to Titania's Song, Life and Limb, and Xenograft.
Tireless Provisioner triggers, creating a Food or a Treasure token.