Hollow Trees

Land
Hollow Trees enters the battlefield tapped.

You may choose not to untap Hollow Trees during your untap step.

At the beginning of your upkeep, if Hollow Trees is tapped, put a storage counter on it.

{T}, Remove any number of storage counters from Hollow Trees: Add {G} to your mana pool for each storage counter removed this way.¹
Illus. David Seeley

Gatherer Card Rulings [Nov 2009]

• 10/4/2004: It is considered "tapped for mana" if you activate its mana ability, even if you choose to take zero mana from it.
• 10/4/2004: This enters the battlefield tapped even if a continuous effect immediately changes it to something else.
• 10/4/2004: If the land is tapped by some external effect, no counters are removed from it.
• 10/4/2004: Counters are not lost if the land is changed to another land type. They wait around for the land to change back.
• 10/4/2004: Whether or not it is tapped is checked at the beginning of upkeep. If it is not tapped, the ability does not trigger. It also checks during resolution and you only get a counter if it is still tapped then.

Format Legality	Legal in Vintage, Legacy Banned in Extended, Standard, MTGO Classic
Printings (2/7)	Fifth Edition (Rare) Fallen Empires (Rare (U1))