Various types of urban green space, with its large leaf area, dense branches, blocking, filtering, adsorption air of dust, particulates, while also serving as retention, dispersion, absorption of air, the role of toxic gases, which Air can be purified. Forest is a special air purification "filter." For example, in a cement plant two rows of large poplars tied, the amount of dust in the air can reduce 33% ~ 52%. Shows a variety of green plants planted in town, on the regulation of air flow, clean the air has a very important role .
1.2 The climate regulation
First of all, garden plants can adjust the temperature. Landscaping can adjust the temperature, plays the role of cool. In the hot summer months, trees can shade a large leaf area, reflects solar radiation effectively, greatly reducing the direct sunlight on the ground. Evaporation of water through the leaves of trees, can reduce its own temperature, increase air humidity around. Thus summer temperatures than non-green space green space within the low temperature 3 ~ 5 ℃, lower than the temperature in the building area is about 10 ℃. Therefore, the urban green area, with high coverage, can improve the microclimate of the living area. Good place in the green, the summer people will feel fresh air, enjoy the cool air can be refreshing, summer cooling. Winter, trees can reduce wind speed, reduced the intrusion of cold air, woods and the back side, the temperature can increase 1 ~ 2 ℃. Second, the garden plants can regulate air flow. The green areas and non-green areas there are differences between the temperature, the temperature of green space adjacent to the non-green than the lower temperature. Law of diffusion with temperature down, and the air flow to the hot air areas, and sometimes flow rate of up to 1m / s, which can form a slight wind, makes people feel cool. Finally, garden plants can adjust the humidity, the temperature of the "regulator." Plants through leaf transpiration and water, large amounts of water to the land to be released into the air, the air humidity increased. According to the research, because the roots absorb almost all the water evaporates, so the air humidity of the forest is 30% higher than in cities around . As a strong tree transpiration, so that more water vapor, the air moist, and therefore, green areas than non-green areas humidity is 10% to 20%, so as to people in the production, life and create a cool, comfortable climate and environment.
Reduced noise 1.3
More serious noise pollution of modern cities, the noise not only affects the people's normal life, serious harm people's health can also affect the central nervous system and spirit of people's reactions, lead to there lack of energy, fatigue, blood pressure and other symptoms [ 3]. Use of large canopy trees and branches, you can absorb and isolate noise. It has been determined, in the absence of trees lined the streets of tall buildings, the noise intensity ratio of both sides of the street trees planted more than 5 times a large, visible, urban greening is important to reduce noise pollution.
Garden plants are an important part of the urban landscape. Plant mix, beautiful shape, rich spatial variation of the environment. The level of scattered trees, tree of the variety, the size difference between the crown, breaking the flat monotony of the building become a lively, vibrant, urban environment and thus deepened the sense of space and layering. Various types of plant changes with the seasons, showing a different seasonal colors, such as Acer mono, triangle Maple, autumn leaves of red Swiss wood species such as red, gold and silver honeysuckle, chicken and other tree species Viburnum Article persistent ear branches in winter, as cold winter's unique landscape. Flower color is vivid and, therefore, reasonable for the city green, can make the city become colorful, lively, beautiful...