GREEN TRACK— THE REVIEW AND IMPLICATION OF OPEN SPACE PROTECTION IN NORTH AMERICAN METROPOLISES
梳理北美大都市开放空间保护目标的多样性趋势，分析十个典型区域的连接式保护模式，指出生态保护是其他目标的基础，并为中国提出整合现有空间、与城市增长管理有机结合的启示。
In this paper, diversity trends of open space protection goals in metropolis are elaborated, and the same as five highlighting targets such as ecological protection, recreation and well-being, corridor and trail, community reviving and green infrastructure. The form of connecting open space is the vital element to the achievement for the diversity targets and values in emphasized. Ten metropolis areas with their excellent open-space planning in North American are selected for typical examples. Based on the contrast and analyses of connected open space protection development and impact factors, it is indicated that goals conflict can not be completely avoided, so the goals of recreation, corridor and trail, community reviving must built on the basis of the goal of ecological protection, and green infrastructure should be a integrated thinking mode. Then it is summarized that the characters of North American green track embodies in the connecting of open space form, waterfront development and utilization, optimum and effective models of institutional structure and complex multiple, interacting scales and so on. Finally, with the consideration of open space protection reality in China, suggestions such as integrating existing open space, organic bond with open-space planning and urban growth management, a virus approach strategies are put forward.