Chin J Plant Ecol ›› 2021, Vol. 45 ›› Issue (8): 880-890.DOI: 10.17521/cjpe.2021.0025

• Research Articles • Previous Articles     Next Articles

Influence of different de-trending methods on stem water relations of Picea meyeri derived from Dendrometer measurements

XUE Feng, JIANG Yuan*(), DONG Man-Yu, WANG Ming-Chang, DING Xin-Yuan, YANG Xian-Ji, CUI Ming-Hao, KANG Mu-Yi   

  1. and Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
  • Received:2021-01-19 Revised:2021-05-07 Online:2021-08-20 Published:2021-06-04
  • Contact: JIANG Yuan
  • Supported by:
    National Natural Science Foundation of China(41771051);National Natural Science Foundation of China(41630750);National Key R&D Program of China(2018YFA0606101)


Aims The high-precision data measured by the Dendrometer includes not only the stem radial growth process caused by the enlargement of xylem cells but also the reversible changes caused by the consumption and replenishment of the stem water. Our objectives were to assess the difference in stem water relations of Picea meyeri obtained by different de-trending methods and their responses to water conditions in soil and air.
Methods Hourly stem radius variations in P. meyeri and corresponding environmental factors were monitored in the lower limit of the coniferous forest on the northern slope of Luya Mountain, northern Shanxi Province, China. Gompertz growth model (GPZ), linear growth model (LG), and zero growth model (ZG), daily approach (D), and stem cycle approach (SC) were used to fit the stem growth trend in the growing season of 2015. Then, the growth trend and extract five different types of tree water deficit-induced stem shrinkage (TWDGPZ, TWDLG, TWDZG, TWDD, and TWDSC) were removed to characterize the dynamic of stem water relations. Moving window correlation (31 days) and ordinary least square regression were further employed to analyze the responses of different types of stem water relations to soil and air moisture conditions.
Important findings The results showed that: 1) stem water relations derived from different de-trending methods had contrasting trends and amplitude, which could be clustered into three groups: TWDLG and TWDZG, TWDGPZ, and TWDD and TWDSC. Each month, significant correlations between stem water relations in the same group or a lower clustering distance showed, however, TWDLG, TWDZG, and TWDGPZ had weaker correlations with TWD and TWDSC in August. 2) TWDD and TWDSC had a closer and more stable positive relationship with vapor pressure deficit (VPD) than TWDGPZ, TWDLG, and TWDZG did. The responses of all types of stem water relations to soil water content (SWC) varied greatly during the growing season. 3) All stem water relations significantly increased as the water stress (VPD/SWC) intensified (p < 0.05). When the stress was low, TWDSC was most sensitive to the changes of VPD/SWC (R2 = 0.39, p < 0.001), whereas it was not much different from TWDZG (R2 = 0.37, p < 0.001); when the stress was high, TWDZG showed the greatest sensitivity to VPD/SWC (R2 = 0.59, p < 0.001). Our results suggested that the zero-growth model was more suitable to detrend the stem radius variations during the growing season, and provided a crucial reference for predicting the stem water status and dynamics, especially under drought stress.

Key words: Dendrometer, growth detrend, stem shrinkage, moving window correlation, drought