Relationship between the Changing Urban Open Spaces  and Increasing Density in Mong Kok since the 1970s 

Abstract: Since the 1960s, the construction of tall buildings in Hong Kong has continued to increase. In highly dense urban areas, the urban open space (UOS) has changed significantly because of the limited land resource. This paper aims at unfolding the  relations between the pattern of UOS and the increasing density. This study chooses Mong Kok, one of the most critical inner areas in Hong Kong, and investigates three parts of the Mong Kok district to study the UOS system in highly dense built environments. The three parts are planned for comprehensive development or mix-used commercial areas. By examining the “form-logic” theories [1] and research methods of three major morphology schools (German-British school, Italian school, French school) [2], referring to dividing hierarchies from urban planning theories and inspiring from the “Level” conceptions from Open Building theories of J. Habraken [3], the multi-level framework for studying the UOS in high-dense is put forward. Four Levels are defined in this case study: district, community, block, and plot. Moreover, by considering three changing trends of UOS in a high-dense environment, eight major types of UOS are defined. More sub-types are located and defined also. All types of UOS are mapped in the maps of three periods (the 1970s, 1990s, and 2010s). Then, the representative sites of each type in each Level are selected for analyzing the evolution of pattern and building density. Apart from exploring the relationship between changing forms of UOS and increasing density, this study also discusses and interprets the socio-economic reasons and influences behind these tangible performances.  Moreover, the study methods and results can also offer a reference for well understanding for UOS in highly dense urban.