Final answer:
Hermione uses the levitation charm, Wingardium Leviosa, to move a Christmas tree in The Prisoner of Azkaban.
Step-by-step explanation:
In Harry Potter and the Prisoner of Azkaban, Hermione Granger uses the levitation charm, commonly referred to as the Wingardium Leviosa spell, to move a Christmas tree. This spell is a basic charm taught to young witches and wizards which allows them to make objects fly or hover. To perform the charm effectively, a witch or wizard needs to swish their wand, point it at the object, and concentrate on the incantation 'Wingardium Leviosa' with proper pronunciation and emphasis on the 'Levi-o-sa'.