大树法选优及其增益估测的研究

Research on Superior Tree Selection with the Method of Dominant Contrast and Estimation of the Corresponding Gain

在开展火炬松、湿地松优树选择工作中 ,为使“五株优势木对比法”在应用上更简便快捷 ,在研究该方法的优良度与小样地法的缩差值相关关系基础上 ,筛选出运用优良度估测树高、胸径和材积缩差值的 9个回归方程 ,以及仅用胸径 (火炬松 )或树高 (湿地松 )优良度估测材积缩差的 2个回归方程 ;建立起以缩差 U查对入选率 P、选择强度 i的三维换算表 ,以及用胸径或树高优良度估测材积缩差及其估测误差查算表。提出了确定优良度选择下线的依据 ,简化了估测遗传增益和选择效果的方法。此外还发现 i值随 U值增加而逐渐迫近时 ,P值迅速下降 ,因此 ,要选出一定数量的优树 ,i值定界不宜太高 。

On the basis of studying the correlation between the degree of superiority of the dominant contract method and the differential value of the sample plot method, nine regression equations used to estimate the differential values of height, DBH and volume of Pinus taeda and Pinus elliottii by the degree of superiority of the corresponding trait, and two regression equations for estimating the differential value of volume by only the degree of superiority of DBH (for P. taeda) or that of height (for P. elliottii) were established. A three-dimension conversion table was established, in which selection rate (P) and selection intensity (i) can be found out directly according to the differential value (U). The basis of determining the prescribed minimum of the superiority degree was posed. The method of estimating the genetic gain and selection effect was simplified. Besides, it was found when the value of i increases and closes to the value of U, the value of P decreases rapidly, therefore, in superior tree selection, it is not a good idea to determine the value of i at a very high level, otherwise, few superior tree can be selected.