How did a war, which occurred in the southern China current 2,000 years ago, could have a lasting impact that it still feels today on the agricultural land of the region? It was in fact enough of a military decision to shape for centuries the landscape and the environment of the Delta of the Pearl River, in the heart of the province of Guangdong, known for its titanic capital of 14 million inhabitants, Guangzhou.
According to a study carried out by researchers from the Chinese Academy of Sciences, published in the journal Science Advances, a war launched by the Han Empire-which reigned on China from 206 BC to 220 AD has led to major landscape transformations. Following a fire orchestrated by Han dignitaries in the city of Panyu, an entire species of cypress – the marsh cypresses – was practically eradicated.
The trees, pushing in swampy areas, would have burned until reaching the surface of the water, leaving behind their submerged strains, as explained by the magazine online Ars Technica. In the soils marked by intensive agriculture, only 2,000 km² of peat of water remains, remains of an old ecosystem of wetlands where elephants, tigers, crocodiles and tropical birds were prospered.
Important layers of peat – this organic matter composed essentially of dead plants – today cover the secrets of this agitated past, and tell us the story of a territory still bearing the stigma of the fire of a part of the province of Guangdong.
The result of a general in a disturbed spirit
Ning Wang, one of the main authors of the newly published study confirms: “These peat layers are locally called” buried old forest “, because many buried trees seem fresh and most of the stumps are still standing”. Ning Wang and his colleagues used carbon 14 dating of the exterior rings of the strains to estimate the end of trees, which occurred about 2,100 years ago.
The historical stories evoke a major disaster which would have taken place around 111 BC in the Delta of the Pearl River, then territory of the Kingdom of Nanyue, which dominated a large part of the current province of Guangdong. It would be an attack launched by the Han dynasty against the Nanyue. After having managed to take the city of Panyu, a commander called Yang could then had a fabulous idea: why not set fire to the whole city, to be sure of having settled this story once and for all?
Ning Wang thus confirms that the fire “Not only destroyed the city, but has also spread out of control in the surrounding forests.” These are the consequences of this uncontrollable fire that are still visible today for those who know where to look for.
The tigers, elephants, rhinos and green peacocks that populated the area all disappeared, quickly replaced by crops of rice, wheat and barley, as evidenced by the pollen grains found in the clay layers still covering the peat.
“Most of the populations of G. Pensilis (Cypresses of the Chinese marshes, editor’s note) are today small and fragmented, unable to fulfill the ecosystem functions which they once provided ”underline the authors of the study. Still according to the researchers, this quasi-space is undoubtedly attributable to the Han war against the Kingdom of Nanyue… occurred over 2,000 years ago.
