长汀水土流失区生长季马尾松树干液流密度特征

应用热扩散探针测定福建长汀水土流失区生长季马尾松东南西北4个方位的树干液流密度,并比较不同人工治理措施下马尾松树干液流密度的特征,利用自动气象站同步记录环境因子变化,以探讨先锋树种的水分生理生态特征及其对环境变化的响应.研究表明,马尾松4个方位的树干液流密度日变化均呈现单峰型变化规律;南向树干液流密度峰值最高,日变化幅度也最大;东、西、南、北4个方位的液流密度差异显著(P<0.01),但各方位液流间呈现显著的线性关系;树干4个方位液流的启动时间与太阳辐射之间存在约3个小时的时滞;4个方位液流与环境因子相关性均极显著(P<0.01),其中与液流密度相关性最强的是空气温度,其次为土壤温度和太阳辐射,4个方位液流受环境因子的影响程度存在差异;不同治理措施下的马尾松液流密度日变化规律相似,但数值差异显著(P<0.01),经过人工施肥的样地马尾松树干液流密度峰值明显高于未施肥的样地.

Sap Flux Density of Pinus Massoniana during Growing Season in the Soil Erosion Area of Changting County

By using thermal dissipation probe,sap flux density(SFD)of Pinus massoniana was measured at east,west,south and north orientations on trunk during growing season in the soil erosion area of Changting county.The SFD under different management patterns also was compared.At the same time,the environmental factors were recorded by automatic weather station.The characteristics of pioneer trees water ecophysiology and whole tree sap flow responses to local conditions were discussed.The diurnal changes of SFD appeared single peak,and the peak value of SFD on the south orientation was higher than the others,and its diurnal change range was wide.Within one tree there were significant differences(P<0.01)in SFD at four orientations on the trunk.However,the SFD at different orientations showed significant linear correlation.Time lag between SFD and PAR was about three hours,but strong correlation(P<0.01)existed between SFD and environmental factors.Air temperature was the most important factor and then soil temperature,solar radiation,influence of these factors were different to SFD at four orientations.Diurnal variation of stem SFD was similar under the different management patterns,but the SFD values of them were significantly differences(P<0.01).The peak values of SFD under fertilization were significantly higher than that under no fertilization.