The trunk of a tree is directly attached to the roots of the tree. A stem is one of the two main structural axes of a vascular plant. The word ‘trunk’ is used while referring to a tree whereas the word ‘stem’ is used while referring to a plant. Read more: http://www.differencebetween.com/difference-between-stem-and-vs-trunk/#ixzz1NFygeIb0

What do you exactly mean when you ask: "What do you think?" It has nothing to do with what people think. stem = the stem of flower trunk = trunk of a tree