What Is a Windbreak?

The windbreak forest is a forest community that uses the functions of forest protection, greening, purification, wind and sand fixation, soil and water conservation, and water conservation to prevent natural disasters, maintain infrastructure, protect production, improve the environment, and maintain ecological balance. According to its protection purpose and effectiveness, it is divided into water conservation forest, water and soil conservation forest, windbreak sand fixation forest, farmland pasture protection forest, road protection forest, bank protection forest, coastal defense forest, environmental protection forest and so on. ^[1]

The tree species of coastal defense forests in South China are mainly Casuarina equisetifolia and Ligustrum lucidum; the main tree species for sand control and afforestation in the coastal areas of the south are Kulang trees; Hainan Coastal Defense forests, experts advocate the use of coconut trees, Casuarina equisetifolia and other tree species; Casuarina equisetifolium can be selected ,

Generally speaking, forest belts can be divided into three types: compact structure, dense structure and ventilation structure according to the ventilation coefficient and dredging degree of the forest belt. Protective forests to prevent wind damage and promote ecological balance. Windbreaks can reduce wind speed and protect farmland, orchards, and other production and living buildings from wind damage. The width of the windbreak forest belt can be determined according to the actual situation. In areas with severe sandstorms or frequent typhoon attacks, multi-row broadband windbreak forests that are perpendicular or at an angle to the wind direction are often established to prevent the reduction of large winds. Windbreak forests must be constructed with deep roots and tall trees, including poplar, willow, eucalyptus, and casuarina. Windbreaking should be strictly prohibited

The Three North Shelterbelt was completed from 1979 to 2050, a major forestry ecological project in northern China for a period of 73 years. It has been implemented for 35 years and completed the construction of the fourth phase of the project. The project includes the Northeast, North China, and Northwest, starting from the Uzibeli Pass in Xinjiang in the west, to Bin County, Heilongjiang in the east, 4480km in length from east to west, and 560-1460km in width from north to south, covering Beijing, Tianjin, Hebei, Shanxi, Inner Mongolia, Shaanxi, and Ningxia. , Qinghai, Liaoning, Jilin and other 13 provinces and municipalities, 55 county flags, construction area of 4.07 million km2, accounting for 42.4% of China's land area. The project spans the arid, semi-arid, and sub-humid arid regions from west to east, including desert Gobi, the Loess Plateau, arid deserts, mountain saline-alkali lands, and forest grasslands, with 83% of deserted land and 85% of desertification nationwide. The land and 67% soil and water loss area are distributed in this area. The natural conditions are very complicated and the engineering is difficult. Based on the natural conditions in the Three North Regions, a comprehensive shelter forest system combining belts, nets, patches, trees, irrigation, and grass was used in the project construction. Based on field visits, the author introduced the current situation and current situation of the Three-North Shelterbelt in detail through field investigations, analyzed the forest degradation status and causes of degradation in the Three-North Shelterbelt, and proposed restoration solutions for the forest degradation of each tree species. In addition, the characteristics, varieties and methods of repairing and updating the selected tree species for protection forest are introduced in detail in the future. ^[2]

Windbreaks and windbreaks affect wind erosion in two ways. The first is to reduce the wind speed on the leeward side; the second is to shorten the field length, thereby reducing wind erosion. At present, the following methods have been used as windbreaks: create 1-10 rows of windbreaks of trees and shrubs, plant narrow strips of crops, and build snow walls, wooden fences, stone walls and earth embankments. The effectiveness of each windbreak depends on the wind speed, wind direction, and shape, width, and porosity of the windbreak. When the wind direction is at right angles to the windbreak forest, the wind speed near the forest belt can be reduced by 70-80%, and the wind speed at a height of twenty times the belt can be reduced by 20%. ^[3]

In order to understand the effect of the width of the windbreak forest on the wind speed distribution on the leeward side, a model test of the windbreak forest was carried out in the wind tunnel. The drag force acting on the windbreak can be measured in the wind tunnel with a drag gauge. This drag can be used as a sign of the aerodynamic characteristics of the windbreak. The results show that the types of wind speed distribution on the leeward surface are significantly affected by the width of the windbreak forest.

Windbreak Agriculture and Farmland Windbreak

The current situation of windbreak forests in Hokkaido, Japan, have coexisted with the farmland development of the Toshiba period since ancient times. In 1896, the "Regulations on Colonial Zoning Facilities" was formulated in the Department of Public Affairs, and the establishment of windbreak belts was planned. According to statistics, the area of windbreak forests in 1981 was 40,885 hectares (including state-owned forests and privately owned forests), an increase of 4,910 hectares compared to 1963. In recent years, due to agricultural modernization, deforestation of paddy fields and dryland windbreak forests has been severe, especially in the diagonal slopes of eastern Hokkaido. The reason is that people have not fully understood the value of windbreak forests. The author's research results on windbreak forests believe that windbreak forests have a good effect on improving the climate. Therefore, how to change from logging to afforestation is worthy of research and discussion by forestry and meteorological experts. Effects of windbreak forests Windbreak forests, according to the purpose of disaster prevention. ^[5]

Windbreaks and wind-resistant cultivation of cloves

After Typhoon "Dawei" in Hainan, the wind damage of clove garden and clove tree in Wanning city was investigated and analyzed. The analysis results showed that: the wind damage index of the seedling lilac tree protected by the windbreak forest was 78.7%; the wind damage index of the dwarf lilac tree protected by the windbreak forest was 38.6%; and the wind damage index of the natural Casuarina forest was 32.4%. Clove is not a wind-resistant tree species, but after being dwarfed, its wind-resistance is close to that of Casuarina natural forest. ^[6]

Windbreak forest windbreak forest ecological restoration

The May 2009 spatial resolution (2.5 m × 2.5 m) ALOS remote sensing image was used as the remote sensing data source to analyze the land use type and current status of Dafeng Forest Farm. At the same time, it combined the field survey to summarize the ecological environment problems existing in the forest farm. Further proposed ecological measures and projects such as expanding the scale of ecological infrastructure, increasing regional biodiversity, and improving the stability of the overall ecosystem, with a view to improving the local forest structure, improving forest management and management capabilities, increasing regional biodiversity, and improving the overall ecosystem Stability and other purposes. ^[7]