Urban greening solutions

Part of the materials and energy of the urban ecosystem are inputting from or outputting to the outside of the city. But many important living conditions, like clean air, silent environment, pleasant climate, beautiful scenery and outdoor recreational resources, cannot be improved completely by the input and output. To maintain the positive circle of urban ecosystem, a city needs adequate natural ingredients, the most important of which is green plants. The urban greening is an indispensable part of the city construction.