Steeped in Tradition

An ethnobotanist traces the history of tea along ancient trade routes from southwestern China to the Tibetan plateau
Watch a slideshow of photos from the Tea Horse Road in Tibet and China. Photos: Michael Freeman
August 11, 2011


Selena Ahmed was sipping a cup of tea with her Ph.D. advisor in his New York office when talk turned to the tea that grows deep in the forests of Myanmar and Yunnan province of southwestern China. An ethnobotanist who studies human-environment interactions and how plants are managed and used in different cultures, Ahmed was intrigued.

She eventually embarked on a four-year adventure in which she learned how Camellia sinensis, the plant that produces tea, is grown, how tea is prepared and savored and what it means to the environment and those whose lives revolve around it.

“Tea,” notes Ahmed, “is the second most widely consumed beverage in the world, after water.”

Starting in 2006, Ahmed spent four years off and on in southern Yunnan and the Tibetan plateau, visiting the tiny mountain villages where people have been brewing and drinking tea for centuries. Tea thrives in sub-tropical Yunnan province. Some 1,300 years ago Tibetans acquired a taste for tea and, unable to grow it themselves because of their country’s high elevation, began trading their warhorses for it to meet China’s demand to protect its empire. The trade route became known as the Tea Horse Road, or Southwest Silk Road, the oldest tea trade network in the world.

“Tea is a whole world,” says Selana Ahmed.Ahmed’s research resulted in her doctoral dissertation, several scientific articles and now a coffee-table book called Tea Horse Road: China’s Ancient Trade Road to Tibet (River Books Press, 2011), written with the renowned photographer Michael Freeman. Those projects complete, she continues to travel to Yunnan for her new project as a postdoctoral fellow in the Department of Biology in the School of Arts and Sciences. She is assessing how climate change is influencing the taste and therapeutic properties of tea and how the farmers who grow tea are responding.

In the course of her journeys she has witnessed how the rapid development of the Chinese economy and the demand for organic tea from urban areas in China and other countries have affected many tea-growing communities and their surrounding environment.

She has also coped with frigid weather, endured relentless rainstorms and waded through knee-high piles of manure. And she has even learned to enjoy Tibetan butter tea, a salty concoction of yak butter and tea.

The Art and Science of Tea

The tea people drink in many households in Yunnan and Tibet is a post-fermented type called pu’er, and there is an art and ritual to its preparation. Households often prepare several infusions, pouring boiling water onto the tea leaves numerous times. Each infusion lasts between 30 seconds and a few minutes. The first infusion is usually thrown out, either to release the aroma, as some villagers report, or, as others maintain, to make an offering to the spirits. Still others say the reason is to eliminate the caffeine content or to simply clean the leaves.

These tea masters, farmers and connoisseurs know their tea intimately. “When you get people together,” says Ahmed, “they’ll say the third infusion is their favorite—or the seventh. Or they’ll talk about where they think the tea comes from: 'This was grown on a mountain with a southern-facing slope, and there must be a river nearby.’ ” Such an assessment may come after only a sip or two.

Tea is cultivated several ways in Yunnan. It grows deep in the forest, where tea plants soar some 50 feet high, and in what are called agro-forests, areas managed by indigenous communities where shade-grown tea plants are interspersed with other trees. Some indigenous communities also cultivate tea in fields with crops such as rice and corn. The majority of tea in Yunnan is found on the carefully tended, sloping green terraces that create the tea fields with which most of us are familiar.

In several respects, tea grown in that familiar way may be inferior. When Ahmed brought samples back to her lab in the United States, she discovered that the tea from indigenous agro-forests and mixed-crop fields was not genetically distinct from the tea grown in other systems, but had the most genetic diversity and phytochemicals, compounds believed to contain certain beneficial health properties.

Modern tea terraces are usually planted with clones—rooted cuttings that are genetically identical—and thus have less genetic diversity than the agro-forests and mixed-crop fields where several local types of tea are grown.

Regarding phytochemicals, Ahmed theorizes that tea from agro-forests and mixed-crop fields has to work harder to fend off pests and other herbivores and develops these compounds in response. Cultivated tea in terrace gardens, pampered with pesticides, herbicides and fertilizers, would have less need to develop such a phytochemical defense response.

Weathering Hardships

In conducting the research for her dissertation and book, Ahmed drank as many as 30 cups of tea a day during her travels. She reveled in the generosity of the villagers, who always offered her a place to sleep, sharing their one room and their best food and drink with her and her translator.

But there were hardships. The blanketing rain of the monsoon season left her feeling damp for weeks at a time. She gave up wearing boots, because they never dried out, and instead turned to flip flops and occasionally went barefoot; there was no way to avoid the mud. Manure, too, clung to her clothing when she found herself having to wade through a pool of knee-high fertilizer to reach a particular household for an interview.

On the Tibetan plateau she had to withstand the unrelenting cold that begins in November and lasts until March. Here, as in all the mountain communities of the region, she was able to find some respite. She learned to warm herself in the hot springs, which offered a dramatic view of snowcapped mountains. Looking out at that panorama, she could hear the ding, ding of yak bells and smell burning juniper incense.

These days when she returns to Yunnan, Ahmed is documenting climate change as well as changes that have occurred in the short time since she began her research. Pu’er tea has climbed in value. In the past decade, it has increased more than 100 times from around $1.20 per kilo to $140 at her main study site. The demand for organic tea from agro-forests has increased as people outside the region have become more concerned about the use of pesticides and yearn for the bittersweet taste of shade-grown tea.

At the same time, economic expansion in China has led to the expanded commercialization of natural resources and the introduction of roadways, electricity and in some cases even Internet access in remote areas. As a result, many households have more income and more opportunities to send their children to school.

Yet not all community members are necessarily pleased. In the past, says Ahmed, households focused on a sense of community and tea held multiple values. While some communities still hold ceremonies to thank their ancestors for the gift of tea, many young people are more interested in the money that can be earned from this ancient harvest. Even their diets are being affected. Traditionally, staples in Tibetan communities have been butter tea and roasted barley. Now young people, like their counterparts in western countries, eat potato chips and drink Coke.

Although she no longer drinks 30 cups a day, Ahmed still loves tea. She drinks everything from grassy Japanese sencha tea to sweet oolongs and black tea. When she brews a cup of the pu’er tea brought back from her travels, she relishes the bittersweet taste and the sense of time and place it summons. She can even tell which household prepared the tea, because she is able to discern how it was pan-fried and dried.

She often thinks about how tea connects farmers in one area to consumers in another area and how this relationship has evolved. “Tea,” she says, “is a whole world.”

Marjorie Howard can be reached at