Pine contains compounds called terpenes, like α-pinene and limonene, which are touted in wellness circles for their stress-reducing and mood-boosting properties. Aromatherapy brands frequently promote pine essential oils with terms like “refreshing” and “uplifting,” suggesting there’s something inherently calming in the chemistry of the tree itself.

But that idea doesn’t hold up scientifically, according to [neuroscientist Dr. Rachel] Herz. She says the perception of scent occurs in the amygdala-hippocampal complex, otherwise known as the primary olfactory cortex. It is this mechanism that drives pleasant experiences around particular scents.

— Read more in Why smelling a pine tree can instantly lift your mood at Popular Science.