Most static abilities, like Warden's, only work on the battlefield:
112.3d Static abilities are written as statements. They're simply true. Static abilities create continuous effects which are active while the permanent with the ability is on the battlefield and has the ability, or while the object with the ability is in the appropriate zone. See rule 604, "Handling Static Abilities."
There are a bunch of exceptions to the rule "static abilities work only on the battlefield." Most of these exceptions are obvious:
112.6a Characteristic-defining abilities function everywhere, even outside the game. (See rule 604.3.)
112.6b An ability that states which zones it functions in functions only from those zones.
112.6c An object's ability that allows a player to pay an alternative cost rather than its mana cost functions in any zone in which its mana cost can be paid (which, in general, means it functions on the stack). An object's ability that otherwise modifies what that particular object costs to cast functions on the stack.
112.6d An object's ability that restricts or modifies how that particular object can be played or cast functions in any zone from which it could be played or cast.
112.6e An object's ability that restricts or modifies what zones that particular object can be played or cast from functions everywhere, even outside the game.
112.6f An object's ability that states it can't be countered or can't be countered by spells and abilities functions on the stack.
112.6g An object's ability that modifies how that particular object enters the battlefield functions as that object is entering the battlefield. See rule 614.12.
112.6h An object's ability that states counters can't be placed on that object functions as that object is entering the battlefield in addition to functioning while that object is on the battlefield.
112.6i An object's activated ability that has a cost that can't be paid while the object is on the battlefield functions from any zone in which its cost can be paid.
112.6j A trigger condition that can't trigger from the battlefield functions in all zones it can trigger from. Other trigger conditions of the same triggered ability may function in different zones.
Example: Absolver Thrull has the ability "When Absolver Thrull enters the battlefield or the creature it haunts is put into a graveyard, destroy target enchantment." The first trigger condition functions from the battlefield and the second trigger condition functions from the exile zone. (See rule 702.53, "Haunt.")
112.6k An ability whose cost or effect specifies that it moves the object it's on out of a particular zone functions only in that zone, unless that ability's trigger condition, or a previous part of that ability's cost or effect, specifies that the object is put into that zone.
Example: Reassembling Skeleton says "
: Return Reassembling Skeleton from your graveyard to the battlefield tapped." A player may activate this ability only if Reassembling Skeleton is in his or her graveyard.
112.6m An ability that modifies the rules for deck construction functions before the game begins. Such an ability modifies not just the Comprehensive Rules, but also the _Magic: The Gathering_ Tournament Rules and any other documents that set the deck construction rules for a specific Constructed format. However, such an ability can't affect the format legality of a card, including whether it's banned or restricted. The current _Magic: The Gathering_ Tournament Rules can be found at <
www.wizards.com/wpn/Events/Rules.aspx>.
112.6n Abilities of emblems, plane cards, vanguard cards, and scheme cards function in the command zone. See rule 113, "Emblems"; rule 901, "Planechase"; rule 902, "Vanguard"; and rule 904, "Archenemy."
Tarmogoyf has a characteristic-defining ability, which works everywhere:
604.3. Some static abilities are characteristic-defining abilities. A characteristic-defining ability conveys information about an object's characteristics that would normally be found elsewhere on that object (such as in its mana cost, type line, or power/toughness box). Characteristic-defining abilities function in all zones. They also function outside the game.
604.3a A static ability is a characteristic-defining ability if it meets the following criteria: (1) It defines an object's colors, subtypes, power, or toughness; (2) it is printed on the card it affects, it was granted to the token it affects by the effect that created the token, or it was acquired by the object it affects as the result of a copy effect or text-changing effect; (3) it does not directly affect the characteristics of any other objects; (4) it is not an ability that an object grants to itself; and (5) it does not set the values of such characteristics only if certain conditions are met.
