Reasons for the formation of dry-hot valley

The formation of dry-hot valley is mainly due to the rich light and heat resources, hot climate and serious soil erosion in this area.

Dry-hot valley is the result of complex geographical environment and local microclimate. When water vapor condenses in these areas, it causes heat release, water vapor humidity decreases and air temperature increases. In the valley with closed terrain, the forest vegetation here is difficult to recover due to excessive water loss caused by dry heat. The lack of water makes the land barren in a large area, and the topsoil on the slope of the valley loses in a large area, exposing a large area of bare soil and bare rocks.

Accompanied by the climate in the dry-hot valley, there is another peculiar natural phenomenon-wind burning. As the name implies, it is the general wind that can make foreign objects burn. Some people call it the "Flame Mountain" wind. Once there is a burning wind crossing the border, the climate will become hot and dry, just like a sauna. Warming will make crops and fruits premature, and strong wind burning will lead to drought and forest fires.

Distribution and influence of dry-hot valley;

Dry-hot valleys in China are mainly distributed along Jinsha River, Yuanjiang River, Nujiang River and Nanpanjiang River, such as Panzhihua, Yunnan and Guizhou. Dry-hot valleys are mainly distributed in the middle and upper reaches of major river basins in China, with a distribution area of about 40,000 km2 and a soil erosion area of 60. 15%. The typical section of soil erosion modulus in China reaches 1400 ~ 1500t/km2.

The climate is hot and dry, and the natural conditions are very bad. Under the influence of long-term strong human interference and natural factors, the ecosystem of dry-hot valley is extremely degraded, and its structure and function are on the verge of collapse. It is a typical ecological fragile zone and degraded ecosystem in China's river basins, and it is also the key and difficult area for afforestation in Yunnan Province and even the whole country.