生长季水曲柳树干液流密度的特征

应用热扩散技术测定帽儿山不同径级水曲柳样木生长季的树干液流，初步分析和对比优势木、中等木和被压木树干液流密度的特征及季节变化趋势。结果表明，水曲柳树干液流密度变化具有明显的昼夜节律性，中等木液流密度变化呈单峰曲线，被压木液流密度变化曲线近似梯形，优势木液流密度变化呈弧形曲线，水曲柳中等木液流密度明显大于被压木和优势木。不同天气条件下液流密度日变化规律大不相同，阴雨天液流密度值较小且变化曲线十分不规则，波动性较大，甚至出现多峰曲线。生长季，优势木和被压木日液流通量最大值均出现在7月初至8月耒，分剐为1032．481／（m^2·d）和l063．78I／（m^2·d）；中等木液流通量最大值出现在6月初至6月末，为2260．911／（m^2·d）；优势木和被压木日液流通量最小值出现在9月份，中等木日液流通量最小值出现在生长季未期。，随季节推移，生长季各月份液流密度均值基本逐渐减小，进入生长季末期（10月）基本处于微弱渡动状态。水曲柳优势木和被压木6月份和9月份液流密度平均值均小于中等木，7月份和8月份液流密度月平均值非常接近；中等木液流密度平均值6月份最大，优势木和被压木的液流密度最大月均值出现在7月份，

Study on Trunk Sap Flow Density Characters of Manchurian Ash in Growing Season

Trunk sap flow of manchurian ash sampling lrees in different diameter classes was measured by thermal diffusion technology during growing season, and the character and seasonal change trend of trunk sap flow density among dominant wood, medium wood, and suppressed wood were analyzod preliminarily and compared. The results showod that trunk sap flow density change of manchurian ash had olwious circadian rhythm, sap flow density change of medium wood showed a siclgle peak curve, sap flow density change, cttrve of suppressed wood approxinxated trapezoid, sap flow density ehange of dominant wood showed arc curve, and the sap flow density of medium wood of manchurian ash was significantly greater than suppressed wood and dominant wood. The diurnal change regulation of sap flow density under different weather conditions was different markodly, the flow density value in rainy clays was small and its curve was very irregular, volatile, or even multi-peak curve. In growing season, the diurnal sap flow flux maximum of dominant wood and suppressed wood appeared from early July to August last, respectively 1 032.48 L/ （m^2·d） and 1 063.78 L/ （m^2·d）. The diurnal sap flow flux maximum of medium wood appeared from early June to June last, as 2 260. 91 IV （m^2·d） ; The diurnal sap flow flux min- imum of dominant wood and suppressed wood appeared in Seplember, the diurnal sap flow flux minimum of medium wood appeared in the late gruwing season. With the season going, the sap flow density mean of every month in growing season decreased gradually, and remained weak fluctuation slate in the late growing season （October）. The sap flow density mean of dominant wood and suppressed wood of manehurian ash in Jane and September was less than medium wood, and the sap flow density mean was approximate in July and Oetoher. The sap flow density maximum mean of medium wood was in June, but the sap flow density maximum mean of dominant wood and suppressed wood appeared in July.