不同木材结构树干液流对比研究

采用热扩散法,对东北东部山区代表主要木材解剖构造的水曲柳和樟子松树干液流密度动态特征进行研究,并同步测定光合有效辐射、气温、空气相对湿度、风速、土温、土壤容积含水量等因子。结果表明,水曲柳和樟子松在生长季不同时期晴天的树干液流密度日进程一般为单峰型,水曲柳日最高液流峰值为430.53 cm3.cm-2.h-1,明显高于樟子松(142.43 cm3.cm-2.h-1)。晚上及凌晨液流量占全天比例在生长季结束后,明显增加,其他时期低于20%,说明水曲柳和樟子松存在根压。水曲柳和樟子松树干液流密度变化呈单峰曲线,平均液流密度分别为12.26、6.49 cm3.cm-2.h-1。影响树干液流密度日变化的主导因子为光合有效辐射和水汽压亏缺,二者对主导因子敏感度相当。

Comparative study on stem sap flow of non- and ring-porous tree species

By the method of thermal dissipation,this paper studied the dynamic characteristics of the stem sap flow of Fraxinus mandshurica and Pinus sylvestris var.mongolica,the two major classes of wood anatomy,non-porous(coniferous) and ring-porous,at the Forest Ecosystem Research Station of Maoershan Mountain during growth season.Air temperature and relative humidity,soil moisture,and soil temperature were also measured.The results showed that on sunny days,the diurnal variation of sap flow density presented mono-peak pattern,mostly occurred from 9 AM to 14 PM.The maximum sap flow density was three times greater in F.mandshurica than in P.sylvestris var.mongolica.The ratio of sap flow quantity at nighttime to those in whole day was less than 20%,except in later autumn,indicating the effect of root pressure.After all leaves fallen till mid-October,there still existed sap flow.The seasonal average sap flow density was 48% higher in F.mandshurica than in P.sylvestris var.mongolica.Effective photosynthetic radiation and deficient vapor pressure were the dominant environmental variables affecting the diurnal variation of sap flow density on sunny days.