When Sylvan Primordial enters the battlefield, for each opponent, destroy target noncreature permanent that player controls. For each permanent destroyed this way, search your library for a Forest card and put that card onto the battlefield tapped. Then shuffle your library.
1/24/2013 You search and shuffle your library only once.
7/1/2013 If Sylvan Primordial’s enters-the-battlefield ability resolves but one of the target noncreature permanents isn’t destroyed (perhaps because it has indestructible or it regenerated), it won’t count toward the number of Forest cards you can put onto the battlefield.
2/1/2014 If an opponent has any legal permanents to target, you must target one of them.