Greenbound Summoning( Lost Empires of Faerûn, p. 8)
You are learned in a long-forgotten manner of summoning once practiced by the Eaerlanni elves of the High Forest. Creatures answering your call are automatically imbued with the powers of the forest.
Ability to cast any summon nature's ally spell,
All animals that you summon using summon nature's ally acquire the greenbound template (see page 173) for as long as the summoning spell lasts.