Definition and threshold measurement of narrow land development intensity in province scale based on coordinated development

The coordinated development of Beijing-Tianjin-Hebei has become a major national strategy. Hebei Province in China, is not only the key bearing of the extracted non- capital function and where Xiong'an New District is situated, but also the crucial "short board" for the expected cooperation, demanding urgently to overcome various shortcomings, to undertake industries and to accelerate local development. Previous studies have directly or indirectly defined land development intensity as the ratio of the construction land area to the total area within a region, designating the area of the construction land as the numerator and the regional land area as the denominator. However, due to the constraints of natural conditions, development planning of ecological red line protection and arable land protection, part of the land within a region is not suitable for exploitation and utilization. Taking account of these limitations, in this paper, we adjusted the numerator and the denominator of the original land development intensity and tried to propose the concept of "narrowed threshold of land use intensity", which was defined as the ratio of the size of regional construction land to the natural land area suitable for construction. The threshold was the theoretical maximum under the red line constraint of ecological and farming policy in the region. The scale of development and construction accounts for the proportion of natural conditions suitable for the construction of land area. Taking Hebei Province as an example, we measured the current status, situation value and threshold of the narrow-scale land development intensity of the province, and proposed the feedback adjustment of the narrow development intensity threshold under the expected correction. Through defining the "narrowed threshold of land use intensity", we measured the largest demanded area of construction land in Hebei Province under the background of natural growth and industrial transfer, as well as the suitable development and construction area constricted by natural conditions and development planning. The result showed that narrow development intensity threshold in Hebei Province was 52.32%. Under the ideal prediction of safeguarding regional self-development and industrial transfer for construction land use, the province's narrow-scale land development intensity situation value in 2030 was 29.34%, which narrow-scale land development intensity in 2016 current situation was 26.79%, and the adjacent threshold coefficient was 0.56, which in 2016 was 0.51. Facing the relatively limited land use intensity threshold, it was suggested that Hebei Province should take the suitability evaluation of land space development and construction as the foundation, combine the reasonable demand of urbanization and industrialization and the requirements of ecological space protection, rationally arrange the transfer industry from Beijing and Tianjin, implement land agglomeration development and classified protection, as well as optimize the pattern of land space development, in order to provide land resource protection for realizing the optimal utilization and major development of Beijing- Tianjin- Hebei region. Furthermore, this paper provides reference for the implementation of provincial land use planning strategy and regional policy guidance in Hebei Province.