在北方地区,城市居民区的绿化面积逐年增加,养护管理的技术水平也在不断的提高,但是在园林树木的修剪上,还存在着许多错误的做法,例如部分花灌木的修剪时期不当,秋季修剪花灌木,把已分化的花芽大部分剪掉,影响明年的开花数量；垂榆砧木萌条不能及时修剪,轻者破坏了圆浑的伞形树冠,降低了观赏价值。由于砧木的萌条生 In the northern region, the urban greening area in urban residential areas has been increasing year by year, and the technical level of conservation and management has also been constantly improving. However, there are still many erroneous practices in the pruning of garden trees. For example, Pruning shrubs, the flower buds have been largely cut off, affecting the number of flowering next year; vertical elm rootstock sprouting can not be pruned in time, the light destroyed the round-shaped umbrella canopy crown, reducing the ornamental value. Because of rootstock sprouting students