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引言白榆(Ulmus pumila Linn),属高大乔木,广泛分布于东北、华北、淮北和西北平原等地。它具有喜光、耐寒、抗旱、抗风、耐盐碱,主侧根均发达,对土壤要求不苛、生长快、繁殖容易,经济价值高等特点。是我区平原绿化和广大的干旱草原、丘陵造林的主要的硬阔叶树种之一。然而,我区的白榆类型,绝大部分则存在干形不良、生长较慢等缺陷。这两大不利因子成为发展榆树的限制因子。
Introduction Ulmus pumila Linn, is a tall tree, widely distributed in the northeast, north, north and northwestern plain Huaibei. It has hi light, cold, drought, wind, salt, the main side of the root are developed, the soil is not demanding, fast growth, breeding easy, high economic value. It is one of the major hardwood species afforesting in plain plains and vast arid grasslands and hills. However, the type of elm in our area, most of them are poor dry-shaped, slow growth and other defects. These two unfavorable factors have become the limiting factor for developing elm trees.