Chin J Plant Ecol ›› 2021, Vol. 45 ›› Issue (11): 1191-1202.DOI: 10.17521/cjpe.2021.0106

Special Issue: 碳水能量通量

• Research Articles • Previous Articles     Next Articles

Responses of water vapor and heat fluxes to environmental factors in a deciduous broad- leaved forest ecosystem in Beijing

LI Xin-Hao1, TIAN Wen-Dong2, LI Run-Dong1, JIN Chuan1, JIANG Yan1, HAO Shao-Rong1, JIA Xin1,3, TIAN Yun1,3, ZHA Tian-Shan1,3,*()   

  1. 1School of Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
    2Forestry and Fruit Technology Service Center of Fangshan, Beijing 102488, China
    3Key Laboratory of State Forestry Administration on Soil and Water Conservation, Beijing Forestry University, Beijing 100083, China
  • Received:2021-03-23 Accepted:2021-05-24 Online:2021-11-20 Published:2021-06-28
  • Contact: ZHA Tian-Shan
  • Supported by:
    National Key R&D Program of China(2020YFA0608100);Fundamental Research Funds for the Central Universities(2015ZCQ-SB-02)


Aims The responses of water and heat fluxes of temperate forest ecosystems to environmental factors are hypothesized to vary with time scales. This study aimed to examine the variations of water and heat fluxes in a typical natural deciduous broad-leaved forest ecosystem in Songshan and their response mechanisms to environmental factors at different time scales.
Methods The eddy-covariance (EC) method was used to continuously monitor the evapotranspiration (ET), sensible heat (H), latent heat (LE), soil heat flux (G), vapor pressure deficit (VPD), air temperature (Ta), photosynthetically active radiation (PAR), normalized difference vegetation index (NDVI), and soil water content at a depth of 10 cm (VWC) in a typical deciduous broad-leaved forest ecosystem in Songshan, Beijing in 2019. The wavelet analysis was used to examine the regulation mechanism of biotic and abiotic factors on energy distribution and water vapor exchange at different time scales.
Important findings The mean annual Bowen ratio (β) was 1.53 in 2019. ET had obvious seasonal dynamics, increasing gradually from day 100, peaking in July, and decreasing to the lowest level on day 300. The maximum daily evapotranspiration was 5.01 mm·d-1, the cumulative annual evapotranspiration was 476.2 mm, and the cumulative annual rainfall was 503.3 mm. The main influencing factors of the water and heat fluxes varied with time scales, being mostly controlled by VPD at the daily scale, and by PAR at the seasonal scale. At the diurnal scale, water and heat fluxes lagged 3.36 h behind VPD. At the seasonal scale, water and heat fluxes lagged 8 days behind PAR. At the seasonal scale, PAR had an indirect impact on ET through its effects on VPD and a direct impact on β. The results indicate the time-delay relationships between water and heat fluxes and environmental factors at different time scales, which provides support for selecting the optimal input parameters of the models for quantitatively forecasting ecosystem processes at different time scales in northern temperate deciduous broad-leaved forests.

Key words: evapotranspiration, energy exchange, wavelet analysis, deciduous broad-leaved forest