Rules FAQ

• Each players collect income individually, when he or she becomes the active player. So if you're the first player, you won't be able to use the gold provided by White Tree to marshal cards (because when your opponent, the second player, collects income, your opportunity to marshal cards has already passed).
• If a player collects 0 income (due to Naval Superiority, etc.), but they already have gold in their gold pool (due to Calling the Banners, Long Plan, etc.), White Tree can trigger.