Abstract
Urban forests and street trees are not only a part of the urban landscape, but also having the function of regulating temperature and reducing air pollution. As global warming and extreme weather become more and more frequently happened, the environmental conservation functions of urban forest are receiving more attention at present.When urban green resources are designed poorly, or plants grow in unsuitable environments or are managed badly, the urban ecosystem will become degraded and the function of green resources will reduce. Moreover, there is no healthy seedling standard or regulation for urban purpose yet. Microenvironments around planting area are not well understood. Other problems include wrong planting arrangement and unsuitable planting technique and soil management. As a result, the governmental spend a lot of money on maintenance. It is known that trees have the ability of interception atmospheric pollutants, and urban forests also have the effect of reducing micro-temperature; however, these functions and effects lack effective data can be confirmed.This study will select suitable native plant species (such as antipollution, heat-island effect easing, flood detention, wind-resistant), and increase layers and biodiversity of green resources while considering public preference and forest therapy effect. Both aboveground plants (proper species and management fitting plant physical and growth characters) along with belowground soil ecosystem will be improved. The community is also encouraged to participate this project.This project is also proposed to select a number of common street trees to explore their effects of intercepting suspended particles, heavy metals, organic carbon and water-soluble ions, and to compare the differences of interceptive capabilities among tree species and seasons. Then the monitored intercepted amount will convert dry material deposition velocity data as an input item for the i-Tree model to evaluate the economic benefits of urban forest. In addition, the urban heat island effect is becoming more and more serious under the influence of extreme weather. It will affect the urban environmental quality and cause local climate change and its negative impact should not be ignored. The project will also to explore the differences in temperature and relative humidity among urban forest canopy, understory and surrounding environment at different seasons. The overall purpose of this study is to enhance the resilience and ecological functions in urban area and reduce economic losses of decision units.