JIEFENG KANG

Urban forest, as an essential urban green infrastructure, is critical in providing ecosystem services to cities. To enhance the mainstreaming of ecosystem services in urban planning, it is necessary to explore the spatial pattern of urban forest ecosystem services in cities. This study provides a workflow for urban forest planning based on field investigation, i-Tree Eco, and geostatistical interpolation. Firstly, trees across an array of land use types were investigated using a sampling method. Then i-Tree Eco was applied to quantify ecosystem services and ecosystem service value in each plot. Based on the ecosystem services estimates for plots, four interpolation methods were applied and compared by cross-validation. The Empirical Bayesian Kriging was determined as the best interpolation method with higher prediction accuracy. With the results of Empirical Bayesian Kriging, this study compared urban forest ecosystem services and ecosystem service value across land use types. The spatial correlations between ecosystem service value and four types of point of interest in urban places were explored using the bivariate Moran's I statistic and the bivariate local indicators of spatial association. Our results show that the residential area in the built-up area of Kyoto city had higher species richness, tree density, ecosystem services, and total ecosystem service value. Positive spatial correlations were found between ecosystem service value and the distribution of urban space types including the tourist attraction distribution, urban park distribution, and school distribution. This study provides a specific ecosystem service-oriented reference for urban forest planning based on land use and urban space types.

Urbanization provides both challenges and opportunities for biodiversity conservation, but patterns of urban plant diversity across land uses, especially in Asian countries, remains unclear. To determine these patterns of diversity, woody plants in 174 sample quadrats across various land use types in Kyoto City were investigated. Richness, abundance, and evenness were evaluated at city, land use, and quadrat scales, and biodiversity of different land use types was compared. At the city level, 223 species in 77 families were recorded. At the land use level, residential areas had the highest total biological richness, with moderate to low evenness, while commercial areas exhibited low richness. At the quadrat level, the low-rise residential area had higher species richness than the other land uses. Species abundance and evenness in quadrats were significantly different across land use types for the canopy layer but not for the understory. The results provide insights into urban biodiversity design and management by identifying prior land uses for biodiversity improvement and by highlighting the contribution of residential private yards. Urban heterogeneity, scale, and multidimensionality should be considered when measuring urban biodiversity.

The demand for urban ecosystem services increases with the rapid growth of the urban population. The urban forest is a crucial ecosystem services provider in cities. To achieve a better estimation of urban ecosystem services, an understanding of the link between heterogeneity and ecosystem services within cities is needed. Other than street trees and forest remnants, the contribution of dispersed green spaces should also be considered. In this study, a ground-based sample quadrat investigation of trees across a sequence of land types in Kyoto City was applied. The ecosystem services and monetary values of trees were further calculated using a customized i-Tree Eco tool. The ecosystem services calculated include carbon storage and sequestration, air pollutants removal, and runoff reduction. Ecosystem services of different land use classes were compared at both quadrat and single-tree levels. We found no significant difference across land use for all the ecosystem services at the quadrat level. However, ecosystem services were different across land use at the single-tree level. We performed a species-specific analysis and found that the pattern of ecosystem services at the single-tree level across land use varies with both the service tested and species. Our study suggests that the heterogeneity within a city should be considered when estimating urban ecosystem services. The results also provide insight into the urban green space management of Kyoto City.

A general framework for the analysis of the urban water-energy nexus (WEN) was proposed and a dynamic and quantitative WEN model was developed based on the Long-range Energy Alternatives Planning System (LEAP) and Water Evaluation and Planning (WEAP) tools. Using Xiamen, China, as a case study, eleven future scenarios were designed to explore the impacts of different factors, from both supply and demand sides, on urban WEN. Both water-related energy (WRE) and energy-related water (ERW) were studied to reveal the interconnected relationship between water and energy. We found that most WRE and ERW savings lie on the supply side, except for demand management scenarios, and most scenarios have larger trans-boundary effects than in-boundary effects due to the import of large quantities of energy and water. Industry structure adjustments (oriented toward energy or water savings) and energy-saving measures have better co-benefits in terms of energy and water savings than other measures. Promoting electric vehicles increases electricity imports and related trans-boundary ERW. Such effects should be considered before importing resources from outside city boundaries. Developing high-tech industries might also increase energy or water burdens. Finally, the boundaries of urban WEN research were discussed to promote additional comparable studies. (C) 2019 Elsevier Ltd. All rights reserved.

A water evaluation and planning model (WEAP) for Xiamen City was used to analyze trends in water use and demand between 2015 and 2050. This study was unique in that it considered the water resources of each of the city's five districts' separately, rather than the city as a whole. The water saving potential, water shortages, and water supply alternatives were analyzed under different simulated scenarios. The results show that future water consumption will greatly increase in Xiamen City, and that there will be a water shortage after 2030 without new water supplies. Water shortages will first occur in the Tongan and Xiangan districts, due to established water supply priorities and capacity. Industry restructuring (structural water-saving scenario, SWS) and advanced water-saving technology (technical water-saving scenario, TWS) can result in water saving potentials of 6.97% and 9.82% by 2050, respectively, while adopting both strategies (double water-saving scenario, DWS) can save 16.44%. The prevention of future water shortages requires the implementation of water-saving measures and the use of new water supplies.