Phenology- and light-based parameterization of stomatal conductance model for urban woody species in northern China.

Surface ozone (O 3) poses a significant threat to urban vegetation health, and assessing the O 3 risk across woody species is of vital importance for maintaining the health of urban infrastructure. In the present study, Jarvis-type stomatal conductance model was parameterized for ten urban species in northern China. Incorporating the effects of time of day and diurnal O 3 concentration significantly enhanced the model performance. For different plant functional types (greening trees, greening shrubs, and orchard-grown trees), three parameterizations were established to estimate stomatal O 3 uptake (POD 1 , phytotoxic O 3 dose over an hourly threshold of 1 nmol m−2 s−1). The differences in POD 1 between greening trees and shrubs were primarily due to the difference in their stomatal sensitivity to light. Orchard-grown trees displayed the lowest O 3 removal capacity (lowest value of POD 1) because of their shorter growing season despite of high stomatal conductance. These results indicated that plant phenology and light responsiveness determined stomatal O 3 uptake, and the three parameterizations developed here could be applicable to various urban species in northern regions. Among climatic factors for O 3 risk assessment, O 3 concentration was the most important factor determining annual variation of POD 1 , which was primarily driven by air temperature. However, when O 3 pollution decreased, O 3 concentration exhibited less dependence on temperature and more dependence on light. These findings provide crucial insights for urban policy-makers and environmental scientists aiming to mitigate O 3 pollution effects and enhance urban vegetation health. • Stomatal multiplicative model was parameterized for 10 urban species in north China. • Plant phenology and light responsiveness determined stomatal O 3 uptake across species. • Orchard-grown trees displayed low stomatal O 3 uptake due to short growing season. • O 3 concentration was the most important climatic factor determining POD value. [ABSTRACT FROM AUTHOR]