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利用乔木柳 12年生无性系对比试验林的材料 ,研究了 13个柳树无性系木材基本密度株内径向和纵向的变异模式 ,并对密度选择的时期和取样位置进行了探讨 ,结果表明 :( 1)在 1.3m高度 ,乔木柳无性系各年轮组木材基本密度径向变异多数为“M”型曲线 ,即从木芯向外第 1至第 3年轮组 ( 1～ 6a)的木材密度逐渐增加 ,第 4年轮组 ( 7～ 8a)略有下降 ,第 5年轮组 ( 9～ 10a)又有明显增加 ,至最外侧年轮 ( 11～ 12a)木材密度则显著下降 ,根据各无性系的变异特点 ,分成 3种类型 ,其中无性系 2 2 1的变异较为独特 ,为典型的“N”型 ;( 2 )乔木柳无性系生长期密度变化的规律为 :1～ 2年生时木材基本密度相对较低 ,3～ 4a以后密度相对稳定并接近无性系加权平均密度 ,3～ 4年生时木材基本密度与 5～ 12年生时的测定值相关系数为 0 .789～ 0 .985 ,均达到极显著相关水平 (α =0 .0 1) ,5～ 12年生乔木柳无性系木材基本密度的变异为 6 2 .2 %～ 97.0 %与 3～ 4年生时木材基本密度的值有关 ,3～ 4a作为乔木柳木材基本密度的选择年龄最为合适 ;( 3)供试群体木材密度株内纵向变异模式大多也可用“M”型曲线加以描述 ,具典型的散孔材纵向密度变异特征 ,根据各无性系的变异特点 ,分成 4种变异类型 ;树干高 1.3,3.6和 7.2m处的木
Based on the materials of 12-year-old clonal climber in Jialiu Liu, the variation patterns of radial and vertical distributions in 13 basic tree species of willow clones were studied, and the period of density selection and sampling location were discussed. The results showed that: (1 ) At the height of 1.3 m, most of the radial variations of wood basic density in the climatic cycles of Q. mongolica were “M” curves, that is, the density of wood from 1 to 3 years from the wood core (7 ~ 8a) decreased slightly in the fourth year, and increased significantly in the fifth year (9 ~ 10a). The wood density decreased to the most outer ring (11 ~ 12a) Clonal variation characteristics are divided into three types, of which the variation of clones 2121 is more unique and is a typical “N” type. (2) The law of the density changes of clones in the clonal growth stages is: 1 to 2 years old The basic density of wood was relatively low, the density was relatively stable after 3 ~ 4a and close to the weighted average density of clones. The correlation coefficient between the basic wood density at 3 ~ 4 years old and the measured value at 5 ~ 12 years old was 0.789 ~ 0.985, Reached a significant correlation level (α = 0. 01), 5 to 12 years The variation of the basic wood density of 6.22% ~ 97.0% was related to the basic density of wood from 3 to 4 years old, and the 3 ~ 4a age was most suitable for the selection of the basic density of the wood of Willow juniper. (3) Most of the longitudinal variation patterns of the wood density in the test groups were also described by the “M” curve with the typical variation of longitudinal density of the scattered porous material. According to the variation characteristics of the clones, the patterns of vertical variation were divided into 4 types: Wood at 3.6 and 7.2m