辽西樟子松树干液流运动规律

Stem-Sap Flow of Pinus sylvestris var. mongolica in Western Liaoning Province

为深入研究辽西防风固沙林主要造林树种樟子松的耗水特性,应用热脉冲技术,于2007年8月份观测与分析了辽西章古台地区樟子松在不同天气、不同方位和不同木质部深度的树干液流的变化,结果表明:樟子松树干液流日进程随天气而变化,晴天变化曲线呈双峰型,两次高峰出现在10:00和14:00左右,液流速率分别为19.550、18.118cm·h-1,日累计液流量为41.08L,晴-多云天气次之,雨天最小;樟子松不同方位上液流速率日变化趋势基本一致,但各时段、各方向液流量占该时段液流总量的比例呈不同的变化趋势;樟子松木质部不同部位输水能力差异较大,液流速率最大的位点位于15mm处,10mm次之,20mm及5mm处依次降低,且外层受环境影响较大。

An experiment was conducted to study stem-sap flow of Pinu.s sylvestris var. mongolica, a major species for sand-shifting control forest in Western Liaoning Province, using heat impulse technique in August in Zhanggutai in order to study the transpiration of P. sylvestris var. mongolica. The changes of stem-sap flow were analysed under different weather conditions, different orientations, and different xylem depths. Results showed that diurnal change of stem-sap flow of P. sylvestris var. mongolica changed with weather conditions. Diurnal change of stem-sap flow exhibited a double-peak curve on clear days with two peaks at about 10：130 and 14：00, and the sap flow velocities were 19.550 and 18.118 cm·h^-1 respectively. The diurnal capacity of stem-sap flow on clear day reached 41.08 L, and then followed by cloudy day and rainy day from high to low. The diurnal changes of stem-sap flow in different orientations showed similar tendencies, but the proportion of sap flow in every orientation at each time period to the total quantity of sap flow at the same time period exhibited different changing tendencies. For xylem, water-transferring ability was obviously different at different positions. The sap flow velocities revealed 15 mm〉 10 mm 〉20 mm and 5 ram, and the sap flow velocity in the outer layer was affected greatly by environment.