by Joan Maloof

Earth, my dearest, I will. Oh believe me, no more
of your springtimes are needed to win me over —, one,
ah, a single one, is already too much for my blood.
                           — Rainer Maria Rilke, "The Ninth Elegy"

For years I have been telling my students that our area has no old growth left whatsoever, that this land the early explorers called Arcadia because of its numerous, stately, trees has been completely altered and not a single original forest remains. Depending on my mood the day we discuss this, I either note it with anger or sadness. Recently, however, I heard rumors of the existence of a twenty-acre remnant of old growth forest. In my thinking, twenty acres can barely be called a forest, but still I was anxious to see this scrap. So yesterday when I woke to a true blue dream of a sky I knew right away that this was a day I should visit—as in the e.e. cummings poem, “i thank you god for this amazing day,”—the leaping greenly spirit of trees.

The forest was more than sixty miles away, and detailed directions were necessary to find it down a dirt road. Even before the car stopped I could smell that smell—that sweet, rich, earthy smell—what I used to think was the smell of the mountains. But here I was still on the Delmarva Peninsula, on the flat land, and I was smelling the mountains. Could it be that my ground used to smell like this too—before the grandfather trees were gone? In a time when the tree's breath merged with the breath of the fungi and the birds and the insects?

Author Joan Maloof in an old growth forest. Photo by Rick Maloof.

When we discuss what we miss about forests after they have been cut, it is usually the sight, or the shade, or the species, that we mention; but now I am breathing deeply of a forest gift that I had forgotten: the air! Americans have largely ignored this dimension of the forest's allure, but the Japanese recognize it and have a name for it: shinrin-yoku, wood-air bathing. Japanese researchers have discovered that when diabetic patients walk through the forest, their blood sugar drops to healthier levels. The Japanese have hosted whole symposiums on the benefits of wood-air bathing and walking. I have certainly noticed that I feel better after a walk in the woods; I just didn't know there was a name for my therapy.

So what could be in the forest air that makes us feel better? In a study done in the Sierra Nevadas of California, researchers found 120 different chemical compounds—but they could only identify seventy of them! We are literally breathing things we don't understand; which also means, of course, that when we lose these forests, we don't know what we are losing.

Some of the compounds in the air are coming from the bacteria and the fungi in the soil, but most of the chemical compounds in the forest air are given off by the trees. Trees release volatile organic compounds from little pockets between their leaf cells. There are a number of theories about why they release the compounds: possibly to deter insects, or possibly they are just metabolic by-products and this is how trees eliminate them (having no excretory system). The scientific community is still undecided.

I like to think of the enticing fragrances given off by the trees as a sort of mutualistic reward for humans. If you love how something smells you may be less likely to chop it down. Sort of a Botany of Desire, where the trees are using one of the few wiles they have that work on humans. And I suppose it is not inconceivable that the trees may be altering our perception with their chemicals. The plant's volatile molecules evaporate into the air and come into contact with the sensory neurons in our nasal passageways. The olfactory nerves send messages directly to the limbic system in our brains. This is the system that deals with all our instinctive emotions, including sex, memory, and aggression. The limbic system can most certainly affect our physical bodies, and all of this can happen even without our perception of having 'smelled' anything.

Old-growth buddies: two trees intertwine among the forest's fresh air. Photo by Rick Maloof.

Aromatherapy practitioners work with these plant-produced volatile compounds. They call them essential oils, and they depend on folk wisdom about the effects various compounds will have on our limbic systems. There hasn't been much scientific research done on determining just what effect these oils have. Often I put lavender oil in my bath, because I love the fragrance; aromatherapists tell me it is supposed to be calming. I can't say for certain if it calms me or not. But I know that someone, somewhere, is planting more lavender because I like the way it smells.

The molecules from the trees don't just go up your nose, however. They are also part of the air that goes into your lungs, and, once in your lungs, some of the molecules enter your bloodstream. So when you walk through the forest inhaling that sweet air—the wood-air—the forest actually becomes a part of your body.

The most abundant compounds given off by trees are monoterpenes. There has been a great deal of research done on dietary monoterpenes, and the good news is that they have been shown to both prevent and cure cancer. Many chemotherapy drugs contain monoterpenes. Lemon rinds, in particular, are high in monoterpenes. I could find no research, however, on the effects of inhaling monoterpenes.

Aromatherapists claim that the monoterpenes in pine are anti-viral and antiseptic, good for asthma and respiratory infections. But not surprisingly, there is no medical research to back up their claim. Could inhaling the monoterpenes also be a cancer cure, like ingesting them is? Is shinrin-yoku a valid therapy? And perhaps an even bigger question: Why hasn't the Western medical community researched the physical effects of inhaling the monoterpenes so abundant in the forest air? Might it be because forest air cannot be patented, and consequently there is no money to be made from it?

It is popular to decry the destruction of tropical rainforests—citing the wonder drugs that may eventually be found there. Meanwhile, closer to home, we may have medicines of our own lurking right beneath our noses. Perhaps someday, when your physician asks you to “take a deep breath,” it will be the old-growth air that he or she is referring to.

I hope you don’t have to drive too far to reach it.

Joan Maloof teaches biology and environmental studies at Salisbury University in Maryland. She has an active interest in botany, especially native plant identification. Her current research is centered on a rare sub-alpine plant which grows in the Western U.S.: Corydalis caseana. She is studying plant-animal interactions with an emphasis on the role of bumblebee nectar robbers. She has work forthcoming in the Terra Nova book Progress and Evolution.

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