欧美杨107杨立木生长应变分布规律

Distribution Pattern of Growth Strain of Poplar 107 Clone Tree (Populus ×euramericana cv. Neva)

选取欧美杨107杨为研究材料,通过对正常生长欧美杨107杨立木表面轴向生长应变和伐倒木内部残余轴向生长应变的测定,分析表面生长应变和内部残余生长应变的分布规律。结果表明:正常木表面轴向生长应变的变化幅度范围为:-853.10～-213.43με。Z2和Z5在周向上表面轴向生长应变的变化幅度较大,而Z1,Z3,Z4变化幅度相对较小;在不同树干高度研究中,表面轴向生长应变在树干基部向上与整体树干高度10%位置之间,生长压应变(即生长拉应力)随着树高增加逐渐增大,随后数值开始下降;双因素方差分析表明,不同单株和不同周向位置对表面轴向生长应变影响不显著,但不同高度对生长应变影响显著;欧美杨107杨正常木内部残余轴向生长应变变化幅度范围-1279.00～960.20με,其径向变异模式为在树干外围表现为轴向压应变(即拉应力),由树皮向里,在中心板南侧第5或6年轮和中心板北侧第4或5年轮处,轴向压应变转换为拉应变(即压应力),随后Z2和Z5在中心板南向第3年轮处出现拉应变最大值,而Z3则在中心板北向第3年轮处出现拉应变最大值,各单株在内部残余轴向生长应变径向变异的整体趋势图如开口向下的抛物线,其顶点在髓心处,其二次曲线回归方程为Y(生长应变值)=815.02X2(测试点序号)-69.345X-1902.403,R2=0.775***。

The well distributed and planted poplar clone 107 was selected as studying materials in this study. Surface longitudinal growth strain and inner residual longitudinal growth strain were determined. Both variation patterns of the surface strain and the inner strain were deduced. The result indicated that varied scope of the surface strain was - 853.10 - - 213.43 με, and changing range of the surface strain among different periphery positions was relative narrower at tree Z1, Z3 and ZA, however, larger one was found at tree Z2, and Z5. When it came to variation along tree height, the surface strain increased from basement to upward as compression strain, namely tension stress, and reach the maximum at 10% of total height of tree, and then changed into decreasing. Result of double factor AVONA suggested that there were no significant effect was found both by different trees and different periphery positions on the surface strain, conversely, apparent effect of different heights on the surface strain was detected. Varied scope of the inner strain was - 1 279.00 - - 960.20 με. Radial variation pattern was that the inner longitudinal compression strain （tensile stress） was decreasing from the bark to inside, and turned into tension strain （compressive stress） at the fifth or sixth growth ring at north part of center board and fourth or fifth growth ring at south part of the board. The maximum of tension strain of Z2 and Z5 tree located at the third growth ring of south part of the board, and Z3 tree at the same growth ring of north part of the board. General radial variation trend curve of the inner strain was similar to a parabola with a downward opening, and the maximum value located at pith. Quadratic regression equation of the inner growth strain to number of growth years was Y（inner growth strain） = 815.02 X^2 （number of growth ring） - 69.345 X- 1 902.403, R^2 = 0. 775^＊＊＊.