利用热扩散式边材液流茎流探针（TDP）和微型自动气象站组成的测定系统，对泰山林科院林场麻栎(Quercus acutissima)人工林树干不同高度边材液流及其相关环境因子进行了连续观测，对影响边材液流的主要环境因子进行了相关性和滞后效应分析。结果表明：同一立木，树干上位边材液流流速上升快，高峰期持续时间短，但高峰流速较高，最大流速在0. 002 cm•s－1以上；树干下位边材液流流速上升、下降慢，液流高峰期持续时间较长，最大流速不超过0.001 cm•s－1。太阳净辐射是麻栎边材液流最主要的影响因子，且成正相关，空气温度、空气相对湿度对边材液流的影响较小，空气温度与麻栎边材液流的影响成正相关，相对湿度与边材液流速率成负相关。边材液流与主要环境因子日周期波动在时间上存在延迟效应，延迟效应因树干高度和环境因子而变。树干上、中和下部边材液流与太阳净辐射变化的滞后时间分为80、20和30 min，与空气温度的滞后时间分别为60、130和110 min，与空气相对湿度的滞后时间分别为170、160和90 min。
Aims Water consumption of single trees can be estimated by measuring the sap flow rate in trunk sapwood. Previous studies of sap flow had problems
researching temporal correlations between environmental factors and sap flow because there is a lag time between environment and sap flow due to stomatal regulation in the leaf and water capacitance in the inner tissue of the trunk. Although this method has been used extensively for forest trees, it
has not been reported for Quercus acutissima.
Methods We used a micro-meteorological station and thermal diffusion probes to measure daily meteorological factors such as total solar radiation (Rs),
net solar radiation (TBB), air humidity (RHa), air temperature (TPa), wind speed (Ws), soil temperature (TPs), soil relative humidity (RHs) and the diurnal course of sap flow at lower (1.3 m), mid (4.5 m) and upper (8.0 m) heights of 40 a Quercus acutissimatrunk in May 2005. The research site was on a south-facing hillside of Tai Mountain at the Forestry Centre, Forestry Science Academy of Taishan. Weather factors were sampled at 30 s intervals and recorded as 10 min averages. Sap flow velocity (SFV) was recorded by a Delta-T data logger at 10 min intervals. The temporal response of SFV to climate forcing factors was investigated using cross-correlation analysis over a range of time lags from -100 min to +180 min.
Important findings Patterns of daily and diurnal SFV fluctuation were different at the three trunk heights. SFV in upper trunk sapwood changed quickly and peaked >0.002cm•s-1. SFV in the lower trunk changed slowly and was no more than 0.001cm•s-1.SFV in the mid-trunk was intermediate. The main environmental factors correlated with SFV were TBB, TPa, RHa, although their effects were not similar to each other (TPs and RHs were not significantly correlated to SFV ). TBB showed the strongest (positive) correlation with SFV. TPa and RHa had weaker correlations: positive for TPa and negative for RHa. Correlations ranged from 0.265 to 0 .944 for TBB versus SFV, from 0.409 to 0.869 for TPa versus SFV and from -0.406 to -0.159
for RHa versus SFV. The correlation of sap flow and environmental fact ors indicated that there were lags between SFV and TBB, TPa and RHa. Upper, mid and lower trunk lag times were about 80, 20 and 30 min, respectively, for SFV versus TBB, 60, 130 and 110 min for SFV versus TPa and 170, 160 and 90 min for SFV versus RHa.