So not just the arrow under "Target Land" on most Power Cards, but also, e.g., Range arrows in the text of Powers (eg, Unrelenting Growth) and Range arrows in Spirit Phase actions (like "Move a Presence 1" as a Presence-track ability). Obviously, Power Cards that boost Range (like Reaching Grasp) won't be able to help with Spirit Phase actions, because it's too late in the turn for that (and furthermore, Reaching Grasp is explicitly limited to Powers).
- They do not affect Gather or Push, because there is no Range arrow. (And the definition of those keywords involves "an adjacent land".)
- They do not affect "Your land" or "lands with your Presence" because there is no Range arrow. (And that wording is about what is in the land, not how far away the land is.)
- They do not affect Ranges on other players' Powers (even if played on you), because it is not your action.
It also doesn't boost the Range at which Flame Markers make lands vulnerable to damage/destruction in Rituals of the Destroying Flame.