Temporal and spacial variation of sap flow of Chinese pine(\%Pinus tabulaeformis\%).
Sun Pengsen; Ma Lüyi; Wang Xiaoping; Zhai Mingpu. Journal of Beijing Forestry University (2000)22(5)1～6 [Ch,16 ref.] College of Resources and Environment, Beijing For. Univ., 100083, P.R.China.
Heat Pulse Velocity Recorder(HPVR) and Delta T Automatic Weather Station were applied to study the stem sap flow of Chinese pine (\%Pinus tabulaeformis)\%, which is the main afforestation tree species in north Beijing mountain area. In this article the daily variation of sap flow velocity at different depths below the cambium and the sap flow characteristics under different water stress were studied from April to September of 1999. Results of the statistical analysis by SPSS showed that solar radiation intensity, wind speed, and temperature of atmosphere are the main factors affecting the sap flow, and relative humidity and soil temperature have less effect on it. Statistical model to calculate the sap flow velocity by micrometeorological factors was also provided.