Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (7): 998-1009.DOI: 10.17521/cjpe.2022.0091

Special Issue: 光合作用

• Research Articles • Previous Articles     Next Articles

Response of hydraulic architecture in Fraxinus velutina street trees to the percentage of impervious pavement in Beijing

WANG Jia-Yi1, WANG Xiang-Ping2, XU Cheng-Yang1, XIA Xin-Li3, XIE Zong-Qiang4, FENG Fei1, FAN Da-Yong1,*()   

  1. 1The Key Laboratory for Silviculture and Conservation of Ministry of Education, Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland Administration, Research Center for Urban Forestry, Beijing Forestry University, Beijing 100083, China
    2School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, China
    3National Engineering Laboratory of Tree Breeding, College of Biological Sciences and Technology, Beijing Forestry University, Beijing 100083, China
    4State Key Laboratory of Vegetation and Environment Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093
  • Received:2022-03-09 Accepted:2022-07-06 Online:2023-07-20 Published:2023-07-21
  • Contact: *FAN Da-Yong(
  • Supported by:
    The National Natural Science Foundation of China(32271652)


Aims Understanding and quantifying the variability of drought tolerance and the potential driving mechanism in urban trees are critical to the prediction and management of urban ecosystem stability under global climate change. The objectives of this study were: 1) to identify the branch hydraulic traits of trees at urban sites with different percentages of impervious pavements in Beijing, and 2) to investigate if the drought tolerance of urban trees is adapted to urbanization.

Methods The investigated species in the study was Fraxinus velutina. This species is widely applied to street planting in Beijing. We selected six sites along the north-south axis of the city with different percentages of impervious pavements as represented by normalized difference built-up index (NDBI). The NDBI and monthly surface temperature at each site were obtained by remote sensing. The bench dehydration technique was used to assess site-specific branch vulnerability to drought-induced xylem cavitation. Net photosynthesis rate, stomatal conductance, and maximal efficiency of PSII photochemistry (Fv/Fm) were also measured with a photosynthesis instrument.

Important findings The percentage of impervious pavements was positively correlated with the water potential corresponding to 50% loss of hydraulic conductivity (Ψ50), while Ψ50 was found to correlate with pre-dawn xylem water potential (Ψpd) and vapor pressure deficit. A significant trade-off relation was found between specific conductivity and Ψ50, but not between leaf specific conductivityand Ψ50. The embolism repair ability was significantly positively correlated with Ψpd. The net photosynthetic rate decreased with the increase in percentage of impervious pavement, whereas the Fv/Fm did not show significant difference among sites. The results suggest that the percentage of impervious pavements is one of the key urban environmental indicators affecting the drought tolerance of urban trees. The hydraulic architecture of F. velutinashowed adaptability to the urban environment in the city. The study not only provides important research data for evaluation of the health, resilience, and stability of the urban ecosystems under the scenarios of rapid urbanization and global climate change, but also a theoretical support for decision-makers to formulate practical and feasible management strategies for street planting in Beijing.

Key words: normalized difference built-up index, urban trees, embolism vulnerability, hydraulic efficiency, stomatal conductance