Abstract:

Objective: By constructing the Yangtze River Delta urban forest construction level index, we reveal the spatial correlation of urban forest construction in the Yangtze River Delta region and the evolutionary characteristics of its spatial correlation, break through the previous barriers of inter-regional elements being independent of each other, and analyze the direct and spillover effects of each influencing factor on the long-term and short-term urban forest construction in the Yangtze River Delta in a spatial perspective. To provide reference and decision-making basis for the construction of differentiated urban forests, the integrated construction of the Yangtze River Delta forest city cluster and the integrated ecological green development of the Yangtze River Delta. Method: The entropy-weighted TOPSIS method is used to construct a comprehensive urban forest construction index, which incorporates the carbon sequestration benefits of urban vegetation and measures the urban forest construction level of 41 cities in the Yangtze River Delta from 2006 to 2019, and the dynamic spatial Durbin model is used to analyze the spatial spillover effects of urban forest construction and the short- and long-term indirect and direct effects of factors such as urban economic and social development and the creation of forest cities on the urban forest construction level. Result: 1) The spatial weight matrix based on the inverse of spatial distance is consistent with the extensive spatial relationship of urban forest construction in the Yangtze River Delta, and the global Moran index of urban forest construction in the Yangtze River Delta shows a fluctuating upward trend above 0.244 3. 2) Urban forest construction in 41 cities in the Yangtze River Delta exhibits stable spatially blocky cluster heterogeneity in space. “High-high”(H-H) value clusters, all concentrated in Shanghai, Jiangsu and Zhejiang, forming a development trend of coastal to inland diffusion; the“low-low”(L-L) value clusters are mostly concentrated in Anhui Province, and show a trend of diffusion first and then contraction. 3) The spillover effect of urban forest construction in the Yangtze River Delta is around 0.172, and the direct effects of per capita GDP on the construction level of urban forest in the short and long term are ?0.014 2 and 0.091 4, respectively. The direct and spillover effects of creating forest cities are significantly positive in the short term, but negative in the long term. There are differences in the short-term decrease and long-term increase of the effects of population density, tourism, and tertiary industry share on the construction level of urban forest. Conclusion: There is a significant spatial correlation in the construction of urban forests in the Yangtze River Delta region, economic development puts pressure on the level of urban forest construction in the Yangtze River Delta region in the short term, while economic development drives the development of urban forests in the long term. The increase in population density and tourism and the share of tertiary sector in the long term may force managers to focus on ecological conservation in the hope of obtaining greater ecological benefits. The increase in road area per capita improves the level of forest construction in the city in the short term and radiates to neighboring cities, but in the long term it limits the space for further development of urban forests; after the success of creating a forest city for a period of time managers may further improve the level of urban forest construction and have a positive impact on the forest construction in surrounding cities, but lacks sustainability in the long term.

Key words: urban forest construction, carbon sequestration benefits, spatial spillover benefit, dynamic spatial modle