The dividing line of population density starts from Heihe River in Heilongjiang in the north and extends all the way to Tengchong in Yunnan in the southwest. This is China's famous population dividing line: Aihui-Tengchong Line, which is called "Hu Huanyong Line" internationally. Let's look at the dividing line of population density.
The dividing line of population density, 1, is a straight line drawn between Heihe City, Heilongjiang Province and Tengchong County, Yunnan Province, with a large population in the southeast and a small population in the northwest. This line, also called Hu Huanyong Line, runs from Aihui in Heilongjiang (1956 renamed Aihui, 1983 renamed Heihe) to Tengchong in Yunnan, and is a basic straight line with an inclination of 45 degrees. 42.9% of the land in the southeast of the line is inhabited by 94.4% of the population, with plains, water networks, hills, karst landforms and Danxia landforms as the main geographical structure, and farming has been the mainstay since ancient times; The population density in the northwest of the line is extremely low, and it is a world of grassland, desert and snowy plateau. Since ancient times, nomadism has dominated. It is precisely because of the difference in climate and topography that relevant scholars speculate that the Hu Huanyong line is the product of climate change.
During the Han and Tang Dynasties, the western Loess Plateau and Guanzhong area had warm and humid climates, which could carry more people, thus becoming the political and economic centers of China. In the middle of the Tang Dynasty, the capital was frequently moved from Chang 'an to Luoyang. In addition to political and economic explanations, frequent natural disasters in Chang 'an area are also one of the important reasons. After the Song Dynasty, the climate change showed the trend of "Hu Huanyong direction" day by day, and the population, culture and economic center of China gradually moved south to the Yangtze River basin. During the Ming and Qing Dynasties, although the government made great efforts to govern Gansu, the ecological environment to the west of Hu Huanyong Line was deteriorating, and food self-sufficiency became a problem.
Wang Zheng, a professor at the Institute of Science and Technology Policy and Management Science of the Chinese Academy of Sciences, said that the Hu Huanyong line is the influence area of the southeast monsoon in China. The abrupt climate change from 1230 to 1260 basically established the modern climate characteristics of China. Since this period, the spatial frequency distribution trend of various droughts and floods, especially large floods, has become more and more consistent with the Hu Huanyong line, and it has become more and more obvious in modern times. Therefore, the Hu Huanyong line shows the modern climate characteristics of China. Wang Zheng and other scholars also found that the agricultural production potential fluctuated due to climate change, and the population changed correspondingly due to the different regions of agricultural output, thus forming the Hu Huanyong line, which was later discovered by Hu Huanyong scholars as the geographical dividing line of population.
The 400 mm isoprecipitation line discovered in modern times is the dividing line between semi-humid and semi-arid areas in China, which basically coincides with Hu Huanyong line, and also reveals the high correlation between climate and population density. When the precipitation is less than 400 mm, the land will develop into desertification. As mentioned above, the northwest of the line is generally dominated by grassland, desert, plateau and animal husbandry, while the southeast of the line is rich in precipitation, with different geographical climate and developed agriculture.
"Hu Huanyong Line" draws two distinct natural and human areas. Due to the characteristics of population distribution, the "Hu Huanyong Line" has also become the dividing line of urbanization level to some extent in modern times. The urbanization level of most provinces, autonomous regions and municipalities in the southeast of this line is higher than the national average; The vast majority of provinces and regions in the northwest of this line are below the national average.
Hu Huanyong Line, the demarcation line of population density, was originally named Aihui-Tengchong Line, which was put forward by geographer Hu Huanyong in 1935, and was later called Hu Huanyong Line by American scholars, and was renamed Heihe-Tengchong Line with the change of place names. This straight line connecting Heihe River and Tengchong on Chinese territory is the dividing line of population density in China, but behind it is also the dividing line of agriculture, animal husbandry, economy and natural landscape in China.
"Hu Huanyong Line" represents the 400 mm isoprecipitation line in China. It is the difference of precipitation that causes the difference of climate on both sides of this geographical dividing line, thus forming the difference of natural landscape on both sides, and also making the two sides have different choices between farming and nomadic. So what kind of landscapes and humanistic customs are there in those areas just on this line?
Heihe River in Heilongjiang and Qiqihar
Heihe River, as the northeast starting point of Hu Huanyong Line, was originally named Aihui. This small town on the south bank of Heilongjiang faces Russia across the river. There are many historical sites related to modern times around the city. Wudalianchi, a volcanic site under its jurisdiction, is the most famous scenic spot in Heihe River. The western part of Qiqihar passes by the Hu Huanyong Line, and the most memorable scenic spot of this famous national historical and cultural city named he cheng is Zhalong Wetland, which is called "Hometown of Crane in China".
Inner Mongolia | Hulunbeier, Xing 'an League, Xilingol, Wulanchabu
Leaving Heilongjiang and entering Inner Mongolia, the difference in natural features between the two sides of the "Hu Huanyong Line" is more obvious: Hulunbeier, the largest prefecture-level city in China, has grassland scenery in the south, while Xing' an League is a large forest, from Aershan to Chaihe, and the volcanic lake in the forest is particularly dazzling; Although Xilin Gol is dominated by grasslands, there are also many desert landscapes like Hongshan Dake. The southern part of Wulanchabu, formerly known as Jining, has always been bordered by the Great Wall of Shanxi and Hebei, and the characteristics of the intersection of agriculture and animal husbandry culture are obvious.
Yulin and Yan 'an in Shaanxi Province
After the "Hu Huanyong Line" entered Shaanxi, part of it was accompanied by the Great Wall, and it was almost brushed all over the scenic spots such as the border area of Shanxi, Shaanxi and Mongolia and Laoniuwan. Longzhou Danxia and Yucha Grand Canyon are the double walls of Danxia in northern Shaanxi. Hongjiannao is a freshwater lake in the desert and the home of a rare seagull in the world. The Tongwan City in the wilderness is telling Helian Bobo's ambition of "ruling all nations", while the stone relics that emerged from the world have unveiled the veil of ancient civilization in China layer by layer.
Gansu Qingyang Pingliang Tianshui Longnan
The "Hu Huanyong Line" passing through four cities in Gansu often subverts people's impression of Gansu: Qingyang on the Loess Plateau is more peaceful and cooler than Shaanxi, but there are oil and terraces on the barren land; Tianshui in the south of the Yangtze River is proud of its "wheat accumulation and misty rain", but it is as low-key as a sleeping city, sitting in the second largest city in Gansu; Longnan region belongs to the Yangtze River basin and is the real northwest Jiangnan. Vientiane Cave is only found in the south, and Guan 'egou has a touch of Jiuzhai charm.
Sichuan | Mianyang, Chengdu, Ya 'an and Liangshan
If most of the northeast section of the "Hu Huanyong Line" coincides with the Great Wall, it will be natural after entering Sichuan-from Mianyang to Ya 'an, it coincides with the western edge of Sichuan Basin, Baima Wang Lang is dependent on Jiuzhai Huanglong, Xishan Qing Xue and Shushan Wang set each other off, Mengdingshan tea garden is shrouded in clouds, and Bifengxia trees are evergreen all year round. This line is obliquely cut from Daliangshan, and a super landscape circle is strung together, called "Great Shangri-La".
Yunnan | Lijiang, Dali, Baoshan, Dehong
Lugu Lake at the junction of Sichuan and Yunnan is the northernmost landscape on the "Hu Huanyong Line" in Yunnan, and its quietness is in sharp contrast with the movement of Tiger Leaping Gorge. After crossing the Jinsha River three times, the "Hu Huanyong Line" continued to cross the Lancang River and Nujiang River in the south. The ethnic customs of Naxi, Bai, Nu and Lisu along the line should not be missed. Tengchong is a top tourist city in southwest Yunnan, with excellent natural and cultural features, but there is a small town worth visiting in the southwest-Ruili, which almost crossed the "Hu Huanyong Line".
There is an invisible line in population density demarcation line 3. You may not know it, but it may have affected your life.
This line starts from Heihe River in Heilongjiang in the north and extends all the way to the southwest until Tengchong in Yunnan. From 65438 to 0935, Hu Huanyong, director of the Department of Geography of Central University, groped for this line bit by bit on the map through tens of thousands of data. At that time, he looked at this line from the perspective of population-the northwest of the line is a "lonely desert", accounting for 64% of the territory of the Republic of China, but the population is only 4%; At the other end of the line, there is a "small bridge with flowing water", with only 36% of the country but another 96% of the population. ...
This is the famous population dividing line in China: Aihui-Tengchong Line (called Heihe-Tengchong Line after liberation), which is internationally named Hu Huanyong Line.
In 2009, the Chinese Geographical Society launched the "Centennial Discoveries of Chinese Geography", among which "Hu Huanyong Line" was rated as one of the most important discoveries of China geography in the 20th century.
The luminous map of the National Aeronautics and Space Administration (NASA) also shows that China is brighter at night in the southeast of Heihe-Tengchong Line.
It is a clear dividing line that almost suddenly becomes sparsely populated from the hustle and bustle, just like China people will realize something when they approach this line from south to north, so they stop the pace of outward migration.
This made Hu Huanyong sigh in the paper: "Their numbers are very different."
However, the most embarrassing thing is that this line "does not move."
In the decades since the discovery of this line, many earth-shattering events have taken place: the construction corps stationed troops to defend the border, supported the construction of the third line in the northwest, and educated youth went to the countryside ... China people moved from the east to the west on a large scale again and again, shouting again and again that "man can conquer nature" and went to the vast world to create the future. However, on April 1 2065438, when the number of simultaneous online users of instant messaging software Tencent QQ exceeded 200 million, it was found that users still drew a clear boundary from the northeast to Yunnan-one side was full of QQ online signals, and the other side was dark, just like the population distribution map on the desk of a professor at Central University in 1935.
This line is now called "Hu Huanyong Line". In 2009, among the "Great Discoveries of Chinese Geography in a Hundred Years" selected by geographers, it ranked second only to "Everest Survey".