Is oolong tea made from the STEMS of plant?

No, oolong tea is not made from the stems of the plant. It is made from the leaves of the *Camellia sinensis* plant.

Oolong tea is unique in that it is partially oxidized, meaning the leaves are allowed to partially ferment, which gives it its distinctive flavor profile. While the stems are sometimes used for other tea types, they are not a primary ingredient in oolong.