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我们知道,对树木合理的修枝,可以改善林分的通风透光条件,减少病虫害危害,使养分集中使用,促使树木加速生长,为培育高干、少节、通直优良的干材创造条件。但是过度修枝却会严重地影响树木的生长发育。据调查,四年生定植的小白杨,留2/3的树冠比留1/3树冠的树高和胸径生长分别高70％和8％。白榆幼林经过合理修枝,当年平均高生长量比不合理修枝的大60％—130％。修枝应注意的几方面:
We know that reasonable pruning of trees can improve the ventilation and light conditions of the forest, reduce the harm of pests and diseases, concentrate the use of nutrients and promote the accelerated growth of trees, and create conditions for the cultivation of high-dried, low-cut and straight fine dry materials . However, excessive pruning will seriously affect the growth and development of trees. According to the survey, four-year-old poplar planting, leaving 2/3 crown than the remaining 1/3 crown crown height and diameter growth of 70% and 8% respectively. Ulmus young forest after a reasonable pruning, when the average high growth than the unreasonable pruning 60% -130%. Pruning should pay attention to several aspects: