1. Department of Landscape Architecture, School of Architecture, Tsinghua University, Beijing 100084, China
2. Urban-Rural Ecological Landscape Construction & Research Institute, China Urban Construction Design & Research Institute, Beijing 100120, China
3. Department of Horticulture, Life Science and Technology College, Dalian University, Dalian 116622, China
4. Department of Environmental Art Design, School of Art and Design, Beijing Forestry University, Beijing 100083, China