Vigor and Health of Urban Green Resources under Elevated O3 in Far East Asia

*Laiye Qu, Yannan Wang, Cong Shi, Xiaoke Wang, Noboru Masui,Thomas Rötzer,Toshihiro Watanabe and Takayoshi Koike*

## **Abstract**

Conservation of urban greens is an essential action for city residents, however, declining symptoms and/or traces in the annual ring of trees grown are found in parks and forest stands in a city as well as its suburb with a high level of ozone (O3). Urban greens, including roof-green, provide comfortable conditions for the people and a moderate environment in a city. They are exposed to severe environments; heat, drought, air-pollutions, etc. even with intensive management of the people. How can we proceed with the conservation and wise use of urban greens? We should know the ecophysiological responses of urban trees to such a global environment as well as a local one. Defensive capacities of urban greens should be analyzed in terms of damages caused by biotic and abiotic stresses, and it is important to understand their interactions from the viewpoint of plant-insect/disease. There is a concern that some green areas are suffering from an outbreak of insects and diseases, reducing the vigor and health of urban greens. We discuss these based on specific examples, such as man-made forests, in cities in far east Asia for considering our approach to how to keep urban green resources.

**Keywords:** urban green, plant-insect interaction, ground-level Ozone (O3), nitrogen dioxide (NO2), heat island
