Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (2): 227-237.DOI: 10.17521/cjpe.2022.0100

• Research Articles • Previous Articles     Next Articles

Seasonal dynamics of radial growth and micro-variation in stems of Quercus mongolica var. liaotungensis and Robinia pseudoacacia in loess hilly region

LIU Mei-Jun1,2, CHEN Qiu-Wen1,2, LÜ Jin-Lin3,4, LI Guo-Qing1,3, DU Sheng1,3,*()   

  1. 1State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Northwest A&F University, Yangling, Shaanxi 712100, China
    2College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, China
    3Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, China
    4Xi’an Botanical Garden of Shaanxi Province, Xi’an 710061, China
  • Received:2022-03-18 Accepted:2022-07-06 Online:2023-02-20 Published:2023-02-28
  • Contact: *(
  • Supported by:
    National Key R&D Program of China(2017YFC0504601)


Aims The dynamics of radial growth and micro-variation in tree stems are jointly controlled by species-specific properties and environmental factors, and reflect the characteristics of trees in response to change of environments. Exploring the dynamic characteristics of diameter changes in various temporal scales and their relationships with environmental factors is an important way for revealing the species ecophysiological properties, particularly in semiarid areas where the trees are subjected to high risk of water stress. Our objectives were to clarify the year-round radial growth patterns and dynamics of micro-variations in stems of two semiarid afforestation species, Quercus mongolicavar. liaotungensis and Robinia pseudoacacia,and their response to major environmental factors.

Methods We used DC3 dendrometers to monitor stem diameters in order to investigate year-round dynamics of radial growth and stem micro-variations of the two species, Q. mongolicavar. liaotungensis and R. pseudoacacia, in the loess hilly region. Soil moisture dynamics and the main meteorological factors driving transpiration were simultaneously monitored for analyses on the relationship between stem micro-variation and environmental factors.

Important findings The year-round change of stem diameter in the two species could be divided into a contraction phase during the non-growing season, a transition phase and a growing phase during the growing season. The radial growth of Q. mongolicavar. liaotungensis and R. pseudoacacia started around April 7 and May 4, respectively, and ceased in late September. The diameter changes for the growing phase in Q. mongolicavar. liaotungensis and R. pseudoacacia could be fitted by the exponential saturation growth function and the linear growth function, respectively. The diurnal courses of stem micro-variation for both species were grouped monthly, which showed a typical non-growing (November to March of next year) and a typical growing season (June to September) patterns, while it differed between the two species in April and May, probably due to their species-specific phenological rhythm. The daily maximum diameter shrinkage for both tree species was negatively correlated with air temperature and air vapor pressure deficit during the non-growing season, but positively with those during the growing season. The diameter shrinkage and expansion during non-growing season were strongly influenced by air temperature, while those during the growing season were mainly caused by changes in water within the stem due to transpiration and replenishment. The daily variation of diameter could be used to characterize the water loss through transpiration. The water loss per unit of air vapor pressure deficit in Q. mongolicavar. liaotungensis showed significant difference under two periods differing in soil moisture condition, whereas that in R. pseudoacacia did not reach a significant level, indicating that Q. mongolicavar. liaotungensis adjusted its response level of transpiration to the driving factor. Those results may contribute to clarifying the mechanism of stem micro-variation in the two species and the species-specific strategies for regulation of leaf transpiration in response to changes in soil water condition.

Key words: Quercus mongolicavar. liaotungensis, Robinia pseudoacacia, radial growth, stem diameter micro-variation, diurnal variation, seasonal dynamic