Schematic diagram of karst landforms
At the beginning of the 20th century, when the European geologist Steiler was investigating the Mediterranean coast, he stumbled upon a unique landform landscape: the exposed limestone mountains on the plateau stretched endlessly, small funnels, depressions, and various strange mountain forms could be seen everywhere. Based on its rocky bare characteristics, the scientific community named it "Karst", which means the place where the rock is exposed.
Panorama of Guangxi Muron National Nature Reserve
In geology, "karst" is synonymous with karst landforms, but it is only a hundred years old. However Chinese the description and study of this landform has a long history. As early as the Ming Dynasty, the naturalist Song Yingxing made a more accurate description of the limestone karst landform in his treatise "Tiangong Kaiwu"; Wang Yangming, a university inquirer, also recorded it in the "Pingman Song Fold". The most detailed is Xu Xiake's "Travels of Xu Xiake", which not only introduces a large number of landform types (such as funnels, dry valleys, blind valleys and Tiansheng Bridges, etc.), but also explores the morphology and underground river characteristics of various accumulations in the caves and caves, which can be described as a treasure trove of research on karst landforms in ancient China.
Schematic diagram of the development process of surface rock lava
With the deepening of modern research, karst landforms have appeared in front of the world's eyes in a more scientific image. Originally, the karst area was once a sea, where a large amount of calcium-containing carbonate material was deposited, forming carbonate formations with a thickness of more than 10 kilometers.
Schematic diagram of peak forest peak cluster formation
Later, crustal movements lifted the formation onto land, and the carbonate formation was exposed to the surface of the water and directly subjected to external erosion. Since carbonate rocks are soluble rocks, precipitation is mixed with carbon dioxide to form carbonic acid, under the action of pressure, carbonate rocks are constantly dissolved, and after a long period of time, different karst landscape types are shaped, such as peak forests, peak clusters, caves, etc.
Karst landforms, famous for their exposed rocks and strange rocks, have a fragile ecological environment due to the shallow soil layer and a large amount of exposed rocks. However, the Maolan-Mulian Karst Forest at the junction of Guangxi and Guizhou in China is the largest surviving contiguous karst forest in the world's karst geomorphological areas, with the best preservation and the strongest primordial nature. Today, this karst primary forest is under the jurisdiction of Guangxi Muron National Nature Reserve (hereinafter referred to as Muron Nature Reserve) and Guizhou Maolan National Nature Reserve, which together constitute a magnificent picture of recklessness and beauty.
Schematic map of the geographical location of the Wood Theory Protected Area
Located in Maonan Autonomous County, Huanjiang, Guangxi, the Muron Nature Reserve covers an area of about 108.2 square kilometers and has a forest coverage rate of 97.1%. The karst landforms in the reserve are extremely developed, mainly peak cluster depressions and peak bush funnels composed of cone-shaped mountains, tower-shaped mountains and depressions between them, which are scattered among mountains, and from time to time you can see the karst valleys, basins and caves. The ecosystem is an evergreen deciduous broad-leaved mixed forest in the central subtropical limestone region.
How can such a unique forest be formed on the stone? This starts with the formation of the soil. The main body of the soil is composed of minerals and humus, and minerals are formed by external forces such as weathering and leaching of rocks, which require the accumulation of plants and microorganisms over the years for humus. In the karst region of southern China, strong precipitation also leads to strong leaching, making it easy for organic matter in the soil to flow into rock pores and into groundwater erosion, so soil formation takes a long time. According to scientists, the formation of 1 cm thick soil in the southern karst region takes about 40,000 years, which is much slower than in the non-karst area. After a certain thickness of soil is formed, some drought-tolerant and barren plants (such as orchids) can grow on it and transform the environment with microorganisms to gradually form a positive succession sequence of sparse grass → sparse shrubland → shrubland → shrubland → mature forest.
Vertical distribution map of plants in the woody nature reserve
In the reserve, the unique karst geological and geomorphological conditions have formed many small habitats suitable for the survival of different plants, which are ecologically called "micro-environments". Due to the different environmental conditions such as moisture, temperature and light in different microenvironments, the richness and diversity of plants are determined. The most obvious manifestation is the vertical zonal difference, taking the same mountain body as an example, the bottom depression is relatively sufficient in water, but the sunshine time is shorter, and the moisture-tolerant plants are the dominant taxa, but with the increase of altitude, the soil moisture is more scarce, but the sunshine is sufficient, and the dominant plants have changed to the sunny drought-tolerant taxa.
As far as the living conditions of vegetation are concerned, on the cliffs where the nine rocks are one point of soil, and the stone cracks are not seen, due to the shallow soil and poor water retention characteristics in the karst area, the karst forest plants around the river show more drought-tolerant characteristics, such as thicker leaves, developed root systems, etc. Many tall trees are even deeply rooted in the rocks, intertwined. Similarly, in terms of vegetation composition, the plants of the Huanjiang Karst Forest resemble seasonal dry forests, with the upper evergreen broad-leaved forest mixed with deciduous forest species, while shrubs, vines, herbs, ferns, and parasitic plants grow around.
Unisexual Magnolia
As an important treasure trove of species genes, the Wood Sanctuary not only preserves rich plant resources, but also serves as a breeding ground for many ancient and rare plants. So far, scientific expeditions have found a total of 1064 vascular plants, belonging to 183 families and 553 genera. Unisex magnolias that have been "missing" for more than half a century have also been found here, and even formed a continuous distribution. 20 species of national key protected plants such as southern yew trees, single-seated lettuce, palm leaf wood, and golden retriever have also been effectively protected here.
The reserve is also home to several endangered orchids, such as the chestnut-sloped orchid, the white-flowered orchid, the sclerophyll orchid, the leafy orchid, and the leafy orchid, whose discovery has made the wood theory the focus of the world's attention. In addition to vascular plants, the base of the trunk and the surface of the rock are densely covered with many mosses and algae, and dozens of precious underground fungi grow together, making the bare karst landscape environment a different landscape.
White-flowered orchid growing in the crevices of the stone
The complex ecological environment also provides a good living space for various animals. In the reserve, there are 234 species of animals listed on the Red List of Species in China alone, including the golden leopard, Tibetan chief monkey, black bear, big civet cat and pangolin. In addition, there are countless species endemic to China and insects endemic to Guangxi, such as the Huanjiang Longzhou locust, the tube-toothed plant ladybird, and the small orchid homogeneous bug.
Deep in the primeval forest, there is a long stretch of ancient trade routes, the Qiangui Ancient Road (also known as the Huanjiang Han Dynasty Ancient Road). The ancient road is 24 kilometers long, stretching from The Town of Huanjiangchuanshan in Guangxi in the east to Limingguan in Guizhou in the west. From the Han Dynasty to the Republic of China, the ancient road was once the throat of the Qianchuan region into the two Guangzhous, connecting the five provinces of Sichuan, Yunnan, Qian, Guizhou and Guangdong, and has been the only way for farmers, officials, merchants and the army for generations. In 225 AD, when Zhuge Liang of Shu was recruiting the people of Shuzhong, he transported the people to the border through the Qiangui Ancient Road, and the Dawn Pass in the Mulan Forest was the first pass of the Red Seventh Army from Gui to Qian, and the various departments met at the Panzhai Under the Dawn Pass.
The Maonan people are indigenous to the Muron Nature Reserve, and because they have lived deep in the mountains for generations, they have formed a folk culture that is completely different from the Culture of the Central Plains, the most distinctive of which is the "Dragon Splitting Festival", the sculpture of the noodles and the dance of the noodles.
Schematic map of the five provinces connected by the Qiangui Ancient Road
The special geological and geomorphological characteristics make the Maonan people living in the karst mountains have a special affection for rainwater, and the dragon representing precipitation is the spiritual totem of the Maonan people. Every year around the fifth month of the lunar calendar, the Maonan people hold a huge "Dragon Fen festival" to worship the dragon god and pray for smooth wind and rain and even precipitation. During the Dragon Festival, every household wears a costume, steams five-colored sticky rice and tamales, and folds willow branches and dips sticky rice into the middle hall, which means that the grain is abundant.
Stone mountains and forests everywhere have also given birth to the Maonan people's good at carving skills, the foundation and column of the dry railing building for daily living are made of stone that can be seen everywhere, even the threshold, pig pen, table, stool, cylinder, basin and other small objects are also carved from stone blocks. In addition, the wood carving technique used to carve the noodles is also listed as the intangible cultural heritage of Guangxi Province. Used for festivals and sacrifices, the noodles are divided into 36 sets of 72 kinds of faces in 4 categories: literature, martial arts, goodness and fierceness, which are lifelike, well-made and have high artistic value.