Study On Structure Of Road Greening And The Improvement Of Microclimate In Harbin

Street greening is the important part of city greening. It plays a role of connecting the separate green, afforesting and beautifying the city, purifying the air and reducing the sun heat, which can protect the road so that to creates the safe, happy, comfortable, beautiful and health environment for people.This article was performed to investigate the structural and species composition of street greening of main road in Harbin, and the effect on microclimate of different afforestation form was also studied. The main results are summarized as bellow: There are 32 species trees have be used in street greening of main road in Harbin, comprised 4 gymnosperms, 28 angiosperms, belongs to 21genera 15 families. Minority of which take up high range, such as Populus alba×beroleinsis, Ligustrum obtusifolium, Syringa oblata and so on. Comparing with the rich road greenbelt structure of the driving strips, the structure of street trees is single. The diameter class of the street trees in Harbin is low, which means that most of them are at juvenile stage. The main species of street greening in each part of Harbin is arbor; the species importance of arbor is much bigger than the species importance of brush. Diversity index of road tree in Harbin city is low, minority species occupied more than 50% in each part.Measured diameter, tree height and crown diameter of 14 street trees in Harbin, statisticed and analyzed the dates, the result shows that, the correlativity of diameter breast height and crown diameter are remarkable. The regression model of diameter-tree height is grow model, the regression model of diameter-crown is liner model.By measured the intensity of light, air temperature, relative humidity and wind speed of different street with different shadow area, analyzed the influence to microclimate, comfort degree and air movement of different street greening forms, the result shows that, it has the biggest effect to bating light, cooling and humidification of the street greening from bigger shadow area. The comfort degree of the street with the bigger shadow area on the street is easeful all day, it's good for health. The street greening form bigger shadow area on the street has the better effect for cooling, but between 12:00 to 14:00 the air of the street with smaller shadow area engendered eddying current, it can improved speed of air movement, it is good for the gas exchange between street and forest.