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榆树是米脂县荒山造林的“四大金刚”树种之一,造林面积占用材林总面积的80%。近年来,约60%的榆树相继死亡,严重地影响了该县林业生产的发展。据调查,米脂县栽植的主要是本地家榆和五丈榆,二者均具有耐寒、抗旱、耐干燥瘠薄和盐碱以及抗风等特性,在降水量不足20mm 的干旱草原地区和含盐量达0.2%的土壤上都能正常生长。而米脂县的地理位置、气候、土壤条件,均未超出榆树的适生范围,且该县冬季气温最低的年份也未发生榆
Elm is one of the “Four Diamonds” afforestation forests in Mizhi County, afforestation area occupies 80% of the total area of timber forests. In recent years, about 60% of elm trees have died, seriously affecting the county’s forestry production. According to the survey, the main planting in Mizhi County is local elm and Wuzhangyu, both of which have the characteristics of cold hardiness, drought resistance, dry and barren infertility, salinity resistance and wind resistance. In the dry grassland areas with less than 20 mm of precipitation and salt Up to 0.2% of the soil can grow normally. However, the geographical location, climate and soil conditions of Mizhi County did not exceed the suitable range of elm trees, and the lowest temperature in winter in winter did not occur in this county