PHOTO: U.S.D.A. Forest Service
Imagine breathing deeply in a pine forest. Better yet, just go do it. Ah! Feel better? What is it about that aroma that’s so refreshing? There’s something special about conifers, the class of trees with needles instead of leaves. They hold such a distinctively fresh smell that cleaning product manufacturers have commodified the purity of pines, and with good reason. Researchers who study forests for their health benefits are finding that the smell is just an introduction to all that pines offer.
Describing an aroma is a subjective matter, and many variations exist within families of trees along with subtle differences in odor. Cypress, for example, is described as smokey citrus with mint and sage, the perfect combination to keep the grim reaper away. It was used for mummies’ tombs in ancient Egypt because the wood’s high concentration of essential oils makes it resistant to rot. Cypress has also traditionally been planted around cemeteries to cleanse the smell of decomposition.
The smells from other conifers such as cedar and juniper include spicy and sweet, freshly sharpened pencils, and gin. Cedar blocks or wood shavings repel moths in closets and drawers but have to be refreshed on a regular basis because the volatile organic compounds dissipate. Balsam firs win first place as the most fragrant Christmas tree, with spruces and pines also bringing the fresh scent of the woods indoors for the holidays.
Japanese researcher Dr. Qing Li has studied what makes the smells of conifers so special. As it turns out, the aromas are the product of the trees’ phytoncides. Phytoncides are the substances that naturally occur in many types of plants that ward off insects, other plants, diseases and other threats. Could it be that the trees are also surrounding us with antibacterial and antiviral protection?
Forest therapy, forest bathing, or shinrin-yoku, are new terms for an ancient practice—taking a slow walk in a deep forest and soaking up its healing powers. The intentional practice originated in Japan, and Li has been instrumental in making forest therapy a global movement.
Getting out into the pines works wonders for the mind, body and spirit. It’s common knowledge that trees clean the air, absorb carbon dioxide, contribute oxygen, slow stormwater runoff and cool cities. All those great things trees do for the environment, they also do for us as individuals. They help us slow down, get quiet, inhale and exhale, and chill out.
Li and his team look for certain sensory aspects in a natural space to be considered a healing forest. It doesn’t have to be a pine forest, but those appear to have more healing scent powers. Li’s team assesses the volatile organic compounds that the trees give off, especially alpha-pinene and D-limonene, the distinctive pine and citrus smells.
You don’t have to wait until Christmas to enjoy the scent of pine indoors. Li experimented with diffusing the essential oil of his favorite conifer, the Japanese tree honoki, in controlled indoor environments (in this case, hotel rooms). There was a significant increase in the study participants’ anti-cancer proteins and natural killer cells, which are types of white blood cells that attack and kill viruses and tumors. The participants also slept better and had decreased levels of stress hormones. Other studies used D-limonene in hospitals in Japan and the U.S. to lift moods and help balance the effects of workplace stress; as many as 84 percent of the participants strongly agreed that essential oils contributed to a more positive work environment.
Whether you turn on a diffuser with a few drops of pine essential oil or take a break to sit under a pine tree, get in the habit of inviting phytoncides into your airstream. A little bit of nature’s air purifier goes a long way towoard keeping our immune systems running strong.