SWEATING IN THE WILD: There are no children here, and if there are, they were abandoned like kids in a fairy tale. Jennifer Zwick

I decide to enter the forest because I am tired of the world. It is under water, it is on fire, its president is getting crazier by the minute, it is detonating mountain-shaking bombs for no good reason.

There is a sign planted at the foot of a forest path. It depicts a human on legs and a human on a bike. The one on the bike is in a circle with a line across it. This urban forest invites only hikers.

But the sign is not needed. This forest is obviously too wild for even the most adventurous mountain biker. However, the park across the street—Columbia Way—the 10-acre Cheasty Greespace at Mountain View, does need a sign because its trails have been cleared, are inviting, and alive with kids, parents, and grandparents.

The forest on the other side of the street, the one I'm about to enter, is much larger, around 40 acres. It shares a border with the Jefferson Park Golf Course, which was designed by the Olmsted Brothers, the princes of the king of American parks, Frederick Law Olmsted (the man who designed the most famous park on earth, Central Park), and is called, somewhat confusingly, Cheasty Greenspace or Cheasty Boulevard. There are no children here, and if there are, they were abandoned like kids in a fairy tale. This forest is pretty wild and accessible only to those who really want to flee the city.

Jennifer Zwick

The north section of Greenspace is officially a "natural area," and so is much closer to a protected habitat than a park. The wild Greenspace even has a wetlands.

There has been a lot of talk about this forest in recent years. It's a battleground between sworn enemies: the group called Friends of Cheasty Greenspace at Mountain View versus the group called Friends of Cheasty. The latter group wants to keep this forest open to pedestrians and closed to bikes. They feel that bikers and increased human activity will ruin everything. The Friends of Cheasty, however, is clearly run by cranks. They call recreation "wreckreation" and want to keep things as pure as possible. The other group, Friends of Cheasty Greenspace at Mountain View, is a touch too moralistic for my tastes. They are proud of having tamed their 10-acre section of forest, which, according to their website, was filled with homeless people, junkies, and prostitutes until they imposed a trail system on it. They believe the same can be done to tame the rest of Greenspace.

The wild Greenspace, 1.2 miles in length, begins a block from the Columbia City Station and ends where the elevated Link train leaves Mount Baker Station and turns to the underworld of the Beacon Hill tunnel. The reason why the forest is here is simple to see from a Link train: It's on a steep slope. At the bottom of the forest is the Rainier Vista developments and rows of homes, apartments, businesses, and churches. And at the top of it is the golf course and Beacon Hill residents on 25th Avenue.

Occasionally, power lines cut through the forest, but for the most part it is a space orphaned from human designs and schemes. It has been left alone to grow as it pleased. And grow it has.

In the summer months, this wilderness in the heart of South Seattle is spectacularly green and dense. This is why I'm visiting it now. I want to bathe in its greenery before the leaves turn red and gold and begin to fall. This process, which turns the forest into sticks, usually begins in the middle of October. And a denuded forest is no good for what the Japanese call shinrin-yoku, or "taking in the forest atmosphere through all of our senses." Also known as forest bathing.

According to "Physiological Effects of Nature Therapy: A Review of the Research in Japan," written by the scientists Chorong Song, Harumi Ikei, and Yoshifumi Miyazaki, researchers have found that forest bathing (also called forest therapy) reduces the "stress state" (measured by the cortisol in your saliva), the heart rate, and one's blood pressure, while improving one's immune system. These benefits are experienced almost immediately.

Within 15 minutes of entering a forest, you are a better person. The explanation for these improvements, the researchers believe, is the fact that we, as an animal, have spent more time in forests than in any other environment. Humans have only been out of the woods (so to speak) for "0.01% of our species's history."

AHHHH: Within 15 minutes of entering a forest, you are a better person. Jennifer Zwick

When I enter the forest, almost immediately the temperature on the second-hottest August in recorded history falls.

What's unexpected is how quickly things change. It is like jumping into a pool. The forest has its own climate and even its own sun. The one that cooks the city's cement has an intensity that's not found in the one above these leaves, which are busily producing adenosine triphosphate (ATP), the energy currency of life, and glucose, the food of life.

Inside each leaf in the canopy are cities of chloroplasts—micromachines that, by photosynthesis, convert beams of light from the star in the sky into the stuff that makes life go. You and I are only here because of these micromachines. If they stop their prodigious productivity (the conversion of light, air, and water into food and fuel), we would soon have jack to eat. Every plant that's not parasitical has chloroplasts. Nothing else has come up with this trick (which is as amazing as making something appear with the word "abracadabra"). And if plants, which evolved from green algae, did not leave bodies of water some 500 million years ago and come up onto the land, we would never have left the bodies of water and evolved into mammals.

The light in Cheasty Greenspace is green-bright. And this is because chloroplasts reject that wavelength of light. Red and blue light, yes; green light, no.

And so all of this greenness that symbolizes the environmental movement is basically light that plants can't use. It's junk to them. Indeed, oxygen is also junk to a leaf. And the rise of oxygen into the air 2.3 billion years ago, due to cyanobacteria (the ancestors of chloroplasts—it's complicated), represented one of the greatest pollution events in the history of the planet. This catastrophe for the then-status quo makes our climate-changing times look like child's play. Oxygen is nasty stuff. But without it, large-scale life is not possible. Without it, animals have no protection from the sun's ultraviolet radiation. Without it, we can't burn food efficiently. Without it, trees can't make lignin, the hard stuff of wood—one of the most fantastic substances that evolution has chanced upon. Toxic oxygen made life visible. Remove it, and we go back to a form of life that makes mites look like giants.

WATER: Algae evolved into plants on land 400 million years ago. Jennifer Zwick

I'm walking down a path. It branches. One leads up the hill and the other down. I'm looking for a path that goes deeper into the forest. I head downhill in the hope of finding a northward path. I find one. I walk down it. It ends suddenly in thorny bushes. Life has reclaimed it. I go back to the downward path and continue looking for the one I want.

After the 30 minutes in this forest, I really feel relaxed. I'm sure if a scientist were to test my saliva, my cortisol levels would confirm this for me. It is not surprising at all that in 1984, the scientist Roger Ulrich published a study that showed that hospital patients with views of trees recovered faster than patients with views of walls. Shinrin-yoku is a real thing.

Though my body feels relaxed, my mind is harassed by scientific findings that Peter Wohlleben, a German forester, refers to in his marvelous book The Hidden Life of Trees: What They Feel, How They Communicate. The main finding is that trees live very stressful lives. They have lots of problems, so many things to deal with: bugs, competing trees, hungry mammals.

The peace one feels while sitting in or walking through a forest is mostly an illusion. Is it is like enjoying a few colorful frames of Gone with the Wind and having no idea that it's about a rape, about the South, about its plantations and the violent extraction and exploitation of black African labor, and about a war that tore a union to pieces. All you see is a manly man carrying a woman in a red dress up a red-carpeted staircase and plunge into darkness—and this is the whole of Gone with the Wind. This might be the view of the movie from the perspective of a mite that happens to be on your pillow or couch. It looks so pretty and peaceful—and it's over.

Finding serenity in a forest is just like this. It's an illusion projected by temporal differences. Trees live very slow lives by human standards. But if you sped their shit up, you would see some serious drama in the forest. Wohlleben writes that a farm is eerie because it's so quiet, but a forest is very noisy. Trees are talking in the air and also in the ground, where there is a root/fungal network that Suzanne Simard, a professor of forest ecology at the University of British Columbia, describes as a forest internet.

Simard and other scientists discovered that trees not only share food in the root/fungal network in the ground but also information. Just because you can't hear or see all of these underground exchanges, or the warnings in the air about leaf-eating pests, or the cries for help as a tree gets strangled by some invasive species, doesn't mean all is well.

Indeed, while walking on a path that promises to lead me deeper into the forest, I find a log on the ground that offers an opportunity for a little rest. I sit on it and look west, and find I have a view of a battlefield of a war between big leaf maples (the main trees in this forest) and English ivy (an invasive species loved by rats).

Think of that passage in George Eliot's Middlemarch: "If we had a keen vision and feeling of all ordinary human life, it would be like hearing the grass grow and the squirrel's heart beat, and we should die of that roar which lies on the other side of silence." The war between the invaders and the natives in Greenspace is very loud but, for humans, it is on the other side of silence.

INVASIVE SPECIES: Ivy versus trees. Jennifer Zwick

I walk down many paths, some ending in spots where teenagers got drunk for the first time, one leading to a water-greedy English holly that, with branches of a vine maple, is pulled by ropes attached to a black tarp into a shelter a homeless person once called home. While I walk, I remember what I read on the Friends of Cheasty Greenspace at Mountain View's webpage about prostitutes in the woods.

I begin imagining a forest of the oldest profession. Each big tree in Greenspace has a prostitute leaning on it and waiting for a date. And when the eyes of a hiker are caught by the prostitute, he or she or they nod to a bush where, for cash (no cards in the woods), a good time can be had.

But there are no prostitutes in this forest. There is a woodpecker that knocks on wood. There is a stream that is truly amazing to watch because it has not rained in ages. There is a rotting tire next to this stream. There is a dead tree on which I sit and look up at the sky and see the sun and the leaves and the whole meaning of my life. recommended