邓恩桉优树的选择标准

以1988、1991年种植在广西柳州、桂林两地的邓恩桉为选优林分对象,用5株优势木对比法进行选优,同时研究了优树的入选标准.通过对50株候选优树和250株5株优势木生长量数据、分枝与干形得分值的分析,确定了本次选优的标准为:胸径≥优势木平均胸径1.2倍(或树高≥优势木平均树高1.06倍)、单株材积≥优势木平均单株材积1.44倍、分枝与干形二者综合得分5分以上(含),符合该选优标准的候选优树有26株,入选率为52%.该选优标准适合所研究的林分及与研究林分情况相近的邓恩桉林分的选优.

Study on Criterion for Superior Trees of Eucalyptus dunnii

A selective criteria of superior for Eucalyptus dunnii and the superior tree selections of Eucalyptus dunnii stands in Liuzhou and Guiling,Guangxi in 1988 and 1991 were studied by comparison of tree growth data,branch and stem form score between 50 candidate trees and 250 contrast trees.The results showed that as a superior tree,the DBH(diameter at breast height) was not less than 1.2 times of average DBH of 5 dominant trees(or the tree height not less than 1.06 times),the individual volume was more than 1.44 times compared with the average volume of 5 dominant trees,and the total score in the branch and stem form was more than 5.As this criteria,there were 26 trees selected from 50 candidate trees and the selected ratio was 52%.The selection criteria in the study would be suited for the other similar stands of E.dunnii.