China is home to the world's most diverse collection of plants and flowers -- some 30,000 species, many of them unique or seen only in fossil form elsewhere in the world. A project is now underway to catalog the species, many of them endangered, in the northern mountains of Yunnan Province in southwestern China near Burma. PNS associate Andrea Quong, who has spent two months with that expedition, writes from the field.

GONGSHAN, YUNNAN PROVINCE, CHINA -- This is wild, wild country. In places, the people live in complete isolation -- yet it also feels like the center of the world, the crossroads for an extraordinary variety of ethnic groups and nationalities.

That combination, in a sense, has drawn me here. This region is home to thousands of plant species found nowhere else in the world, many with unique medicinal properties. And many of those species are endangered by development projects designed to meet the needs of China's growing population.

I am here as a member for the second time in a year as part of an expedition dedicated to gathering specimens of the region's plants. We have just returned from a week of intensive hiking and collecting in the nature reserve that extends over much of this northern part of the mountains to Burma in the west and Tibet in the north.

They're building a road from Gongshan in the Salween River valley to Dulongjiang, a small valley in the upper Irrawaddy River basin. Massive upheavals of earth and rock have transformed the richly-vegetated rock faces that I saw last year, and blasting has dumped huge boulders and tons of earth in the Pulah (a tributary of the Salween), narrowing the river bed and swelling the river, already fierce from the rains. It's now pure force -- a muddy, churning, nauseating mess that rips out the stone/dirt path leading from Gongshan into the interior, the lifeline for people from the valley.

All along the path, people transport 150 pound loads on their backs and on pack animals. It's business (they are professional transporters) and survival.

We hiked up to the divide between the Salween and the Irrawaddy divide -- nearly 12,500 feet. It's routine for people passing in and out of Dulongjiang, but it's freezing up there, above treeline: frequently, the rain turns the stone path into a river, and people just wade through the water barefoot, in cotton, totally exposed to the cold and the relentlessly indifferent environment. I wonder how many people die of hypothermia -- obviously there's a higher physical tolerance for stress, but how much can the human body (and mind) take?

It's the midst of the rainy season, and this, combined with the visual shock of the landslides and blasting, has changed my whole perception of this landscape. I felt fear -- not common for me -- crossing this one-plank bridge secured by vines over raging white water, finding myself alone in the stormy alpine far from the life-saving warmth of the hearth fire at the station, realizing that the young men hired to guide had little in the way to protect them from the elements. But it was also totally exhilarating to climb up into a primary forest with giant trees as big as or bigger than the redwoods at home where there is no path finding orchids on the logs, and wondering what each step would bring.

I saw the man guiding me -- a Dulong (ethnic minority ) man -- call down his cattle from the forest, and his bull racing toward us to be fed from the hand. I saw a man holding another by the hair on the top of his head, a stone raised against him for thievery. I saw a lovely garden stretching from the path to a river that drew me down, where a young boy invited me in for apples, peaches, and tea, and told me the farm belonged communally to three Dulong households.

I've been asking questions about history, peoples' migrations, and religion. In one village there is a (Tibetan) Buddhist temple, a Catholic church originally established by French missionaries and rebuilt by a rich Tibetan whose family had been converted, and a Protestant church. In Chinese they refer to Catholicism as tian zhu jiao, referring to a sky (God), and to Protestantism as ji du jiao, defined by Christ. The history is so rich -- all of these minority peoples (who are not minorities in totality here) -- Nu, Lisu, Tibetan, Dulong -- moving across borders and religions, clashing, intermarrying.

There's remarkable isolation (one household head we interviewed had never even been to the prefecture capital) and then there 's a kind of cosmopolitanism that stretches my imagination (Burmese jade traders -- of Pakistani/Burmese/Muslim descent--in Gongshan with their extended families, speaking Chinese; a boy running jade stores in Xishuangbanna (tropical Yunnan) and dreaming of moving to Thailand, where his father works as a driver). Among locals, though, the lingua franca is not putung hua (Mandarin) but Lisu. In most villages, farmer couldn't understand putung hua -- but they welcomed us with copious quantities of corn or wheat or rice mash, oil tea (Tibetan influenced), or the white peaches now in season that are so plentiful they're fed to the pigs.