The Yellow River: dragon tree, untameable river! This is China's other great civilizing river, a magnificent and terrifying river. Its name does not come from the imperial Chinese color, but more simply from its turbulent, muddy waters, which are richer in sediment than any other major river on Earth: each cubic meter of water at the mouth of the Yellow River contains an average of 34 kilograms of silt, compared to just one kilogram in the Nile, a river known for its remarkable sediment load.

These turbid waters, belonging as much to the world of water as to the world of earth, tell a story: a story that begins at the edge of the country, on the Tibetan plateau, where the river begins its slow and meticulous work of erosion, transformation, and transport of matter, like the sap that flows down from the leaves of a tree, laden with sugars produced by photosynthesis.

The headwaters of the Yellow River take shape up there, beginning their transition to the lower reaches in the Loess Plateau, where they do not swell to Amazonian proportions—northern China is very arid—but where they take on an opaque, muddy hue, spreading fertility during floods. The Loess Plateau takes its name from a type of sediment of the same name, beige or brownish in color, formed by wind erosion in desert and periglacial environments. It is found in large quantities in the region, and it is not without poetry that, after an aerial birth and a terrestrial life, the sediment embarks, despite itself, on a thrilling fluvial adventure.

However, this tree is home to the terrible river dragon, the two entities merging into a being that is both benevolent and destructive.

Dragons in Chinese mythology are born in rivers and grow up there for centuries, going through multiple phases of aquatic life to reach maturity. They are born in the form of an aquatic snake, grow a carp's head after a hundred years, become an eel-like creature covered in scales, and become a dragon if they manage to swim up the waterfalls of their birth river, sometimes called “Dragon Gates” in China. Sensory whiskers—reminiscent of those of a catfish—horns, and four clawed legs complete the creature. Upon reaching adulthood at around 1,000 years of age, it acquires supernatural powers, like Shen-Long, a winged dragon that brings rain by walking on clouds, fertilizing the earth as it passes. If he walks too hard, the wind and rain lead to disasters, so he was worshipped to ensure he walked at just the right pace. Even today, 10% of agricultural production still depends on Shen-Long. There is also Di-Long, the master of springs and rivers, who lives in the heavens in summer and in the sea in autumn.

These fascinating myths simply reflect the geography of the Yellow River, which makes for miraculous agriculture in a region with an arid climate and poor soils, it was not for the floods. Throughout history, these floods have been disastrous on several occasions, causing millions of deaths during violent overflows that could shift the course of the river, and particularly its delta, by several hundred kilometers, like a dragon whipping the air with its tail, undulating its entire body in the air, driven by an indomitable power.

It was not far from the junction of the Wei River branch with the trunk of the tree—near the present-day city of Xi'an—that the millennia-old Chinese civilization was born and developed this “hydraulic empire” that would change the history and geography of the continent. Today, the hydraulic empire may have gone too far: the river nicknamed “Chinese Pride” and “Chinese Misfortune” (depending on the season and the floods, undoubtedly) has lost its splendor with a greatly reduced flow, preventing the river from reaching the sea for several months of the year.

How can you keep a tree alive if you cut off its roots?

A tree would be a good candidate to reflect the Yellow River: the Japanese pagoda tree, Styphnolobium japonicum, a tree native to China, despite its name, which comes from the arid plains carved out by the river. In the past, the buds of this tree, which can grow up to 25 meters tall, were used to extract a yellow dye used to color the paper produced by this civilization of great scholars, while its leaves were used to make a decoction when infused in hot water.

The Pagoda Yellow River, Styphnolobium Huaghensis