A few years ago I spent a week doing a retreat next to a stream at the foothills of the Sangre de Cristo mountains in southern Colorado. The ground rules were fairly simple: retreatants were to live as close to “nature” as possible. Instead of sleeping in a tent, I slept either under the stars or under a tarp. I didn’t build a fire, but ate bread, cheese, dried fruits, nuts. I drank water from the stream, and steeped tea in a bottle warmed by the sun. I never used a flashlight and left books, paper, and pen behind.

Like any other heat-seeking mammal, I followed the sun as it climbed the hillside and by sunset I could look out across the broad valley which, millions of years ago, was the floor of a vast sea. During the mornings, I stayed in my sleeping bag until the sun reached the stream, and then, I sat under one of the great pines, and practiced, watching my breath come and go like a gentle wind. It was during one of these morning sessions that it suddenly occurred to me that the Buddha got enlightened under a tree.

This may seem obvious, at least to people familiar with the story of the Buddha’s life, but it nevertheless struck me as something of a revelation. All the Buddhist retreats I had attended in America had taken place inside—in polished black-and-white Japanese-style zendos, or rough-hewn reconverted “barndos,” in luminously colored Tibetan temples, or in city lofts or generic Holiday Inn conference rooms, or in cabins and maybe tents. Of course, I had walked, sat, and lay down under trees, in various states of contemplative ease, but I had never—nor had any of my fellow Buddhists, so far as I knew—meditated under a tree for a sustained length of time, as the Buddha had done.

Of course, there were good reasons for this. Sitting under a tree or beneath an overhanging rocky ledge exposes us to the weather as well as to animals and insects. In the Buddha’s own time, the forests of India contained tigers, rhinos, elephants, cobras, and scorpions. Nowadays, we seem to have reduced the dangerous to the merely distracting. We stay inside to avoid mosquitoes, flies, ants, spiders, stray dogs, and inquisitive neighbors.

Yet there is another perspective. The person who meditates outside for a few days may come to see dangers and distractions as messengers. Such messengers may arrive in surprising shapes. Midway through my retreat I found myself unable to crawl out of a particularly slippery and muddy hole of self-pity—until one morning a yellow jacket landed on my bare stomach, took a good bite, and flew off. Stung into awareness, self-pity and indulgence vanished. A small but crucial turning point, it worked just as well—if not better—than the “encouragement stick” wielded by watchful zendo monitors.

A little later, crossing the stream which divided our wilderness from the civilized amenities of base camp, I noticed a snake. Like the bee that had bitten me, it too was black with a yellowish stripe: a common Western garter snake, the field-guides would say. But there was something a little uncommon, even strange about this particular snake. Poised upright in an elegant S-shaped curve, it didn’t move at all, save for the flickering forked tongue, black as coal with two flame-red tips. We stared at each other. A field-guide might have attributed its unwavering gaze to the fact that snakes have two sets of transparent scales covering their eyes, but the intensity of its perfect stillness and the S-shaped pose made me think of the mythical nagas, the serpentine Indian water spirits reputed to guard treasures hidden beneath the surface of lakes and rivers. So I bowed slowly, three times, forehead to the ground and inhaled the pine resin of the earth. Still the snake did not move. The snake just looked not so much at me as through me, as if to say, “This is how to be, this is how to keep your meditation, in the world you are returning to.”

These outdoor encounters—with the yellow jacket and snake—made me wonder about the Bodhi tree under which the Buddha had attained enlightenment. In the library, I discovered that the Bodhi or Bo tree as it was known was actually one of more than six-hundred species of the Ficus or fig family; that its scientific name is Ficus religiosa, and that was also known in India as the Pipal, Peepul, or Ashvata tree. L.H. Bailey’s The Standard Cyclopedia of Horticulture, refers to it as “The beautiful peepul tree of India,” but H.F. MacMillan, Late Superintendent of the Royal Botanical Gardens, Ceylon, and author of Tropical Planting and Gardening, writes, “The tree is practically of no economic and little ornamental value.” In any case, the bodhi tree was sacred to both Buddhists and Hindus, who believed that the deity Vishnu was born beneath it. Consequently, MacMillan wrote, “Devout worshippers will not cut or injure the smallest seedling or branch of this tree.”

The present Bodhi tree, which grows in the Indian village of Bodghaya on the spot where the Buddha attained enlightenment, is very probably a direct descendent of the original tree. The Buddhist Emperor Ashoka paid homage to the tree in the tenth year of his reign, 259 B.C.E. According to one story, the emperor’s ardent veneration of the tree inspired his jealous queen to have it cut down in the night. Ashoka prayed to the tree and bathed it in milk, and the tree sprang up again within a few days. This time Ashoka built a ten-foot wall around it. Later in his reign, in 288 B.C.E., Ashoka sent a cutting of the tree to Ceylon, where it was planted with great pomp and ceremony in the capital city of Anuradhapura. This tree, according to Macmillan, is “supposedly the oldest historical tree known.”

With time my curiosity grew into an obsession, and three years after my retreat in the Colorado mountains I boarded an Air India jet for the two-day flight to Delhi; then took an overnight train to the market town of Gaya, in Bihar; and hired a tempo—a threewheeled motor-scooter—for the final journey to Bodhgaya.

The trip had taken three or four days, depending on whether you counted the day lost crossing the international dateline. The setting sun cast a dreamy orange glow over the open fields at the edge of town. I left my bag at the Burmese Vihar, showered, and walked through the market, past the open-air stalls selling incense, candles, and red and yellow flowers floating in shallow clay bowls, in through the outer gate past the ragged line of squatting beggars and urchins, and on through the inner gate to the temple complex itself. There were many trees, at least for this part of India, and a series of stone walkways and broad worn steps descending to the entrance of the Maha Bodhi Temple itself—180 feet tall, with buddhas and bodhisattvas carved into every niche.

The tree I was looking for was, in fact, totally obscured by the temple. I came upon it, in the course of my circumambulation, behind the temple in a sanctuary surrounded by a stone fence, six or seven feet high, which could be entered through an iron gate that was now padlocked shut for the night. The tree was shapely and well-proportioned, with four limbs branching out from a smooth trunk which was wrapped, on that first evening, in gold and white brocade. As soon as I saw it, the temple itself seemed reduced to the status of the merely ornamental—nice enough, perhaps—but hardly necessary.

I returned as early as I could the next morning. I was not the first one there. Tibetan monks in their rough red robes were doing prostrations on shiny well-worn wooden boards pointed in the direction of the temple and tree, along with a scattering of Westerners dressed in sweatpants and T-shirts. Tibetans, Bhutanese, and Ladakhis wearing dusty chubas spun prayer-wheels and fingered beads; Thais, Sinhalese, and Burmese laymen and women walked in silent contemplation or animated conversation. Japanese in white shirts and dark trousers walked briskly and snapped photos.

The iron gate to the tree was open this time. Inside were twenty or so Burmese, men and women, wearing the white of pilgrimage. Three saffron-robed monks led the kneeling group in chanting the three refuges in Pali: “Buddhanam saranam gochammi …” The oblong stone marking the diamond seat where the Buddha had sat facing east, his back to the tree, was strewn with flower petals, and shaded by delicate rice-paper parasols.

Over the next few days, I often joined pilgrims from around the world as they entered the little enclosure to pay homage and perform ceremonies. The Japanese, immaculate in black robes over snow-white kimonos, their freshly shaven heads glistening in the sun, chanted the Heart Sutra. Burmese, Thai, and Sinhalese chanted in Pali, Taiwanese in Chinese. Tibetans lit butter lamps and hung prayer flags.

One evening I sat next to a gray-clad Korean nun who sat on her knees, back straight, eyes downcast in rapt concentration. She stayed immobile all day and maybe all night too. The Indian caretaker locked and unlocked the gate to let various groups of pilgrims in as we went on sitting on the far side of the tree. The roots had broken through the circular concrete support, and were raising and breaking out of the confinement of the stone floor. The pale green long-stemmed heart-shaped leaves trembled in the slightest breeze.

Before the Buddha came here he spent years wandering the forests and mountains of India. According to one legend, a deva (or goddess) had appeared to him while he was pursuing his ascetic practices in a nearby cave, which is now the site of a small Tibetan monastery. “This is not the place for a Tathagata (perfected one) to perfect supreme wisdom,” the deva had said, “there is a Pipal tree fourteen or fifteen li from here, under which is a diamond-throne. All the past buddhas seated on this throne have obtained true enlightenment and so will those yet to come. Pray, then proceed to that spot.” And so, the legend says, “The devas going before, led the way and accompanied him to the Bodhi tree.”

The Buddha seated himself beneath the tree on a mat of grass. When he defeated the forces of Mara, he called the earth to witness his accomplishment by touching it with his fingers. The moment he saw the morning star rise in the east, he woke to final enlightenment. None of these events, of course, could have happened to a buddha sitting inside a temple, no matter how grand.

The Buddha spent the weeks after his enlightenment outside as well. He walked back and forth along a course now marked by a raised platform, eighteen stone lotuses representing the flowers that sprang up under his feet. He went up the hill, where “he gazed unwinking at the Bodhi tree,” as a sign now informs us, for seven days.

By the time he moved to the shore of Lake Mucalinda, six weeks after his enlightenment, the monsoon had started, and a great thunderstorm arose. My Rocky Mountain naga had appeared in the form of a garter snake, but the naga king that rose from the lake to shelter the Buddha was a seven-headed cobra. Today a larger-than-life statue in the center of the lake depicts the Buddha seated in meditation on the coils of thenaga king, whose seven flared hoods shield him from the rains like seven parasols.

Years later, the Buddha’s disciple, Ananda, asked the Buddha if a shrine could be built in the Jetavana monastery, so that people would have a place to make offerings during his absence. As recounted in theKalingabodhi-Jataka, the Buddha replied that it was not proper to make a body-shrine, until a buddha had entered nirvana, nor should anyone make a shrine containing an image, “because the connection depends on the imagination only.”

“But,” said the Buddha, “the great Bo tree used by the buddhas is fit for a shrine, be they alive or be they dead.”

“Sir, while you are away on pilgrimage the great monastery of Jetavana is without a visible symbol and the people have no place where they can show their reverence,” Ananda said. “Shall I plant a seed of the great Bo tree before the gateway of Jetavana?”

“By all means do so, Ananda,” the Buddha replied, “and that shall be as it were an abiding place for me.”

As time went on, bodhi trees were planted all over India and Nepal. There is one now in the deerpark in Sarnath, where Buddha first taught, transplanted from the tree the Emperor Ashoka first sent to Ceylon. There is another in Lumbini, the birthplace of the Buddha—a gnarled, twisty, old tree set against the stark sky. When I saw it in that desolate place I felt heartened as if I had come across an old friend who was making the same pilgrimage as myself.

But we cannot be too literal, either about buddhas or trees. As the Indian scholar Dipak K. Barna tells us, “the bo tree was not Ashvata in all cases, the different buddhas having different trees.” And since—according to the Buddha—we are all potential buddhas, any tree can be a bodhi tree. Which means, I think, that if we want to become buddhas we have to find our own trees. Buddhas and trees come together after all.