What are the functions in the garden?

First, the lung function of the city. With the concentration of urban population and the development of industrial production and transportation, more and more waste water, waste gas and burning smoke are discharged, which not only affects the environmental quality, but also directly harms people's health, resulting in headache, tinnitus, vomiting and hypertension. If there are a large number of garden plants, it can constantly adjust the balance of carbon dioxide and oxygen in the atmosphere, improve the environment and promote a virtuous circle of urban ecology. According to experiments, 25 square meters of lawn or 10 square meters of trees can absorb all the carbon dioxide exhaled by 1 person 1 day. Therefore, urban landscaping is called "the lung of the city".

Second, adjust the temperature function. In summer, trees in urban gardens and green spaces can not only block the direct sunlight for pedestrians, but also consume a lot of heat through their own transpiration and photosynthesis. According to the measurement, the temperature under shade in summer is about 3 ℃~5℃ lower than that in the open air. Green plants can absorb 60%~80% sunlight and 90% radiant energy in summer. The ground temperature of garden green space is lower than that of open space.

The temperature of 10 ℃~ 17℃ is 8 ℃~20℃ lower than that of asphalt road, and the temperature of the wall with vertical greening is about 5℃ lower than that of the wall without greening.

Third, the function of adjusting humidity. In daily life and work, people feel the most comfortable relative humidity is 30%~60%, and garden plants can evaporate water through their leaves. According to the measurement, 1 hectare of broad-leaved forest transpiration 2500 tons of water in summer, which is 20 times higher than that of bare land in the same area. 1 ha of Canadian poplar forest, the daily transpiration is 57.2 tons, so it can improve the air humidity, and the street trees in urban greening can also increase the relative humidity 10%~20%. In winter, due to the low wind speed in the green space, air exchange is weak.

Evaporative water of soil and trees is not easy to diffuse, so its relative humidity is also 10%~20%. Due to the increase of air humidity, the urban microclimate is greatly improved and people feel comfortable.

Fourth, the function of purifying air. Air pollution is a major public hazard in urban construction. Among them, smoke, sulfur dioxide, carbon dioxide, hydrogen fluoride and other harmful substances are the biggest threat to human living environment and the main pollutants in the city. Garden plants can absorb harmful gases and purify the air. According to the determination of relevant departments, after passing through the paulownia forest belt with a width of 15 meters, the average concentration of sulfur dioxide decreased by 53.7%, which shows that the greening trees can block and absorb various harmful gases. Therefore, rational allocation of urban landscaping plants can absorb and purify toxic gases and prevent dust from flying; A variety of lawns can prevent dust from coming back, thus greatly reducing human diseases. According to the measurement, the dust reduction of green belts or trees is 23%~52% less than that of non-green open spaces, and the dust is scattered.

The quantity is reduced by 37%~60%. For this reason, citizens call urban landscaping plants "filters" to eliminate dust pollution in cities.

Fifth, the sterilization function. Plants can reduce bacterial pollution and are natural "disinfectors". Because the urban garden green space is covered by flowers, trees and other plants, the dust on it is correspondingly reduced, and the pathogens attached to it are also reduced. In addition, many garden plants can secrete a bactericide, which has a certain bactericidal effect. According to the measurement, the content of bacteria in the air in places with green trees and flowers is obviously reduced by nearly 20 times compared with that in open places. It can be seen that greening plays a positive role in urban environmental sanitation, so landscaping is called the "purifier" of the city.

Sixth, the function of purifying water. Water bodies in cities and suburbs are polluted by domestic sewage and industrial and mining wastewater, which affects environmental sanitation and people's health. Trees can purify water quality, and opaque, colored and smelly water will become transparent after passing through forest belts. Studies have proved that trees can absorb dissolved substances in water, reduce the bacterial content in water and purify water.

Seven, purify the soil function. The roots of garden plants can absorb harmful substances in the soil and purify the soil. Plant root exudates can kill Escherichia coli in soil, increase aerobic bacteria by hundreds to thousands of times, absorb carbon monoxide in air, and promote the rapid generation of inorganic organic matter in soil. This not only purifies the soil, but also improves the soil fertility.

Eight, ventilation, windproof function. Roads, riverside and other green belts in the city are all ventilation passages in the city. If the green belt is consistent with the dominant wind direction in summer in this area, the air flow in the suburbs of the city can be introduced into the city center, which greatly improves the ventilation conditions of the city. In the event of a storm, the green belt can also reduce the wind speed, reduce losses (the wind is too strong to cause disasters) and play a windproof role.

Nine, noise reduction function. Urban landscaping trees can reduce noise interference and are natural "silencers". Due to the heavy traffic and numerous factories in the city, the noise is sometimes very serious. Urban noise is a public hazard, which has a great influence on people's work, rest and health. When the noise intensity exceeds 70 decibels, it will cause dizziness, headache, neurasthenia and other adverse symptoms. Green trees with dense branches and leaves have the function of absorbing and blocking noise waves. For example, planting trees such as cedar and Metasequoia on street trees can reduce the noise by 8 decibels. Therefore, people also call it "green muffler".

Ten, watch rest function. Urban landscaping also has beneficial effects on people's psychology and spirit. In the city, people can see pleasant landscaping, which not only has obvious ecological functions, but also has its superior ornamental value, adding natural beauty to the sultry city. Recreation in a beautiful and quiet garden is conducive to alleviating the tense and hurried pace of the city, eliminating the tension and fatigue caused by long-term work, restoring spirit and physical strength, thus improving the efficiency of study, work and production and bringing development to the city's better economic and cultural construction.

XI。 Ecological and cultural functions. The ultimate and highest goal of landscaping in China is to pursue the spiritual realm of nature, so as to achieve the realm of "although it is man-made, it is natural". It understands the connotation of Chinese culture, is an artistic treasure created by China's 5,000-year cultural history, is a portrayal of a nation's inner spiritual character, and is a magnificent cause that we need to inherit and develop today. Activities such as culture, entertainment, sports and popular science education in gardens can enrich people's lives, broaden people's horizons and learn more knowledge from them, thus enriching people's spiritual life. In the process of building a harmonious socialist society, urban landscaping is the most economical, effective and positive factor in urban ecology, and it is a long-term undertaking with extremely extraordinary significance.

In accordance with the requirements of building a resource-saving and environment-friendly society, we should fully implement Scientific Outlook on Development, adjust measures to local conditions, make rational investment, give priority to ecology, and make green scientifically, and put the concept of conservation into urban landscape planning, construction and management, so as to promote the realization of the national strategic goal of energy conservation and emission reduction, and guide and promote the transformation of urban development mode. And through the innovation of urban greening mode, vigorously build economical landscaping, improve the utilization efficiency of land and water resources, improve the utilization efficiency of funds, and use the least investment.