Circle of Magic: Air & Earth Books 3 & 4

Daja's book: While at Gold Ridge castle to the north of Winding Circle, Daja and the three other mages-in-training who have become her friends develop their unique magical talents as they try to prevent a devastating forest fire from consuming everything in its path. Briar's book: Briar, a young mage-in-training, and his teacher Rosethorn must use their magic to fight a deadly plague that is ravaging Summersea.