连香树和榉树容器苗苗木分级标准研究

Study on Grading Standards for Cercidiphyllum japonicum and Zelkova schneideriana Container Seedlings

选择苗高和地径作为分级质量指标,采用逐步聚类分析方法,对连香树和榉树2树种8个月容器苗的苗木分级标准进行探讨。计算分析得出以下标准:连香树Ⅰ级苗,苗高≥34.65 cm,地径≥0.38 cm;Ⅱ级苗,34.65 cm>苗高≥28.35 cm,0.38 cm>地径≥0.29 cm;Ⅲ级苗,苗高<28.35cm,地径<0.29 cm。榉树Ⅰ级苗,苗高≥26.0 cm,地径≥0.29 cm;Ⅱ级苗,26.0 cm>苗高≥19.5cm,0.29 cm>地径≥0.20 cm;Ⅲ级苗,苗高<19.5 cm,地径<0.20 cm。

The stepwise cluster analysis method was applied to establish the classification standards for 8-month-old container bred seedlings of Cercidiphyllum japonicum and Zelkova schneideriana tree species by choosing the seedling height and basal diameter as the quality indicators for classification. The grading standards for the con- tainer bred seedling of Cercidiphyllum japonicum tree species were as follows ： height ≥ 34.65 cm and basal diameter ≥ 0.38 cm for grade I seedlings; 34.65 cm 〉 height≥28.35 cm and 0.38 cm 〉 basal diameter ≥ 0. 29 cm for grade 11 seedlings ; height 〈 28.35 cm and basal diameter 〈 0.29 cm for grade m seedlings. The grading standards for the container bred seedling of Zelkova schneideriana tree species were as follows ： height ≥26.0 cm and basal diameter≥0.29 cm for grade I seedlings ; 26.0 cm 〉 height ≥ 19.5 cm and 0.29 cm 〉 basal diameter≥0.20 cm for grade Ⅱ seedlings; height 〈 19.5 cm and basal diameter 〈0.20 cm for grade Ⅲ seedlings.