Many people say they enjoy the distinctive smell of the Christmas tree. Conifer trees, such as pine, spruce and fir, have a sharp, fresh and woody smell. The major chemical compounds responsible for their aroma are alpha-pinene, beta-pinene and bornyl acetate.
Great amounts of these compounds are present in conifer resin. This resin plays an important role in plant defence against natural damages. When the tree’s bark is wounded, this resin is exuded from the tree to protect it. Conifer resin also acts as a chemical defence as it contains these compounds.
Conifer resin contains several chemical compound, such as alpha-pinene, beta-pinene, myrcene, limonene and d-camphene. They all belong to the terpene class. A diversity of terpenes are found abundantly in conifer resin. Alpha-pinene and beta-pinene as monoterpene hydrocarbons, are the major constitutes in conifer resin. These two pinenes are structural isomers. Bornyl acetate is also an oxygenated monoterpene with a camphorous and sedative odor.
Pine essential oil is extracted from different parts of the tree. Due to its pleasant odor, it is often used in aromatherapy to boost calm and fresh feelings.