不同修剪方式对元宝枫实生苗枝干生长的影响

Effect of Different Pruning Methods on Branch and Trunk Growth of Acer truncatum Bunge Seedlings

通过研究不同修剪方式对元宝枫实生苗枝干生长的影响,优化元宝枫绿化苗木修剪技术.建立4年生元宝枫实生苗修剪样地,采取重剪、轻剪和不修剪3种修剪方式,连续3年观测样本苗木的树高、树冠、地径、胸径、树冠长度、枝级枝数、枝长、枝粗.用观测值进行样本聚类分析和对应性分析.结果表明:①经修剪的苗木生长指标明显高于未修剪苗木,未修剪样本组内数值差异显著,呈两极分化态势;苗木地径以轻剪苗木平均值最大为6.25cm.生长指标变异系数以轻剪处理后苗木地径变异性最大,系数为33.12%.②轻剪样本评价为优的比例最高.③优树留冠长度与枝下高比例为:1.1~1.4.研究得出元宝枫重剪适宜于5年内幼苗,以调整主干与侧枝生长关系.修剪树冠长度与枝下高控制最优比例为1.0~1.5.5年后中龄苗木适宜轻剪,促进粗生长和树冠发育.

To study the effect of different pruning methods on branch and trunk growth of Acer truncatum Bunge seedlings and optimize pruning methods,the tree height,canopy,ground diameter,DBH,canopy length,branch number,branch length and branch diameter of 4-year-old A.truncatum seedlings under the three treatments were observed for three consecutive years.Cluster analysis and correspondence analysis were carried out on the seedlings samples.The results showed that:①The growth index of pruned seedlings was significantly higher than that of unpruned seedlings.The values of unpruned samples showed a trend of polarization,being significantly different.Light pruning had the maximum ground diameter,being 6.25 cm.After light pruning,the ground diameter variation of seedlings became the largest,with a coefficient of 33.12%.②The proportion of seedlings evaluated as excellent by cluster analysis was the most significant with light pruning effect.③The ratio of canopy length to underbranch height of excellent seedlings was 1.1-1.4.So the seedlings of A.truncatum landscape were suitable for heavy pruning within 5 years to adjust the relationship between the trunk and suitable for light pruning after 5 years to promote the diameter growth and canopy development.The optimal ratio between canopy length and underbranch height of pruned trees was 1.0-1.5.