Welcome to visit Scientia Silvae Sinicae,Today is

Scientia Silvae Sinicae ›› 2026, Vol. 62 ›› Issue (3): 36-47.doi: 10.11707/j.1001-7488.LYKX20240712

• Frontiers and hot topics • Previous Articles     Next Articles

Cooling Effect of a Pinus tabuliformis Plantation in the Suburban Areas of Beijing and Its Environmental Driving Mechanisms

Lili Sun1(),Yanli Sun2,Jingli Wang2,Zeyuan Zhou2,Haiqun Yu2,Wenjing Chen3,Peng Liu1,Yun Tian1,Tianshan Zha1,*()   

  1. 1. National Key Laboratory of Efficient Production of Forest Resources,Beijing Forestry University Beijing 100083
    2. Beijing Landscape Planning and Resources Monitoring Center Beijing 101118
    3. College of Art and Design, Nanjing University of Technology Nanjing 210023
  • Received:2024-11-22 Revised:2025-10-22 Online:2026-03-15 Published:2026-03-12
  • Contact: Tianshan Zha E-mail:17805958627@163.com;tianshanzha@bjfu.edu.cn

Abstract:

Objective: In the context of exacerbated urban heat island (UHI) effect, the evapotranspiration cooling effect of suburban forests plays a crucial role in alleviating UHI and regulating urban heat island circulation. However, the cooling regulation process remains poorly understood. This study aims to quantitatively analyze the transpiration cooling [ΔT(Ef)] and soil evaporation cooling [ΔT(Es)] of Pinus tabuliformis plantation around Miyun Reservoir in Beijing, and determine the regulating factors of these two cooling processes at diurnal and seasonal scales, so as to provide scientific support for the formulation of strategies to mitigate the UHI effect in Beijing. Method: During the growing season from May to November 2021, thermal diffusion probes and eddy covariance methods were used to continuously monitor sap flow density (SFD) and evapotranspiration (ET) of the plantation. The forest evapotranspiration (Ef) and soil evaporation (Es) were calculated, and the major meteorological factors and soil water content (SWC) were simultaneously monitored. Mantel-Test and random forest algorithms were used to analyze the temporal variation characteristics of Ef, Es, ΔT(Ef), and ΔT(Es) in P. tabuliformis plantation and their influencing factors. Result: 1) At diurnal scale, ΔT(Ef) and ΔT(Es) dominated during the day and night, respectively. During the day, air temperature (Ta) had the most significant influence on ΔT(Es), while soil water content (SWC) and shortwave radiation (RSD) significantly influenced ΔT(Ef) (Mantel’s P<0.01, 0.2≤r<0.4). 2) At seasonal scale, ΔT(Ef) contributed more than ΔT(Es), and both ΔT(Ef) and ΔT(Es) were higher in summer than in other seasons. From July to September, the daily averages of ΔT(Ef) and ΔT(Es) were 3.49 and 1.66 ℃, respectively, while Ef and Es had daily averages of 1.64 and 0.77 mm. Ta and SWC were the main environmental factors affecting the seasonal variations of ΔT(Es) and ΔT(Ef), respectively. 3) After parameter optimization, the random forest model showed good simulation results for ΔT(Es) and ΔT(Ef) (R2>0.93). Conclusion: The proportions of transpiration cooling and soil evaporation cooling differ significantly at diurnal and seasonal scales. Thermal conditions (soil temperature and air temperature) and soil water content are the most important factors influencing soil evaporation and transpiration cooling, respectively. Compared to soil evaporation cooling, plant stomatal regulation allows transpiration cooling to quickly respond to the vapor pressure deficit and air temperature.

Key words: evapotranspiration, evapotranspiration cooling, urban heat island effect, sap flow density, soil evaporation

CLC Number: