华北落叶松Larix Principis-ruppre-chtii Mayr因其生长迅速,树杆通直,材质优良,耐寒,耐旱,适应性强等特点,已成为陇东地区主要造林树种,仅子午岭地区已发展5万余亩,国营正宁林业总场已营造2.5万亩。但由于受自然条件的制约(降雨量少、干旱、霜冻、高温),育苗难度较大,严重地影响到华北落叶松发展的进程。国营正宁林业总场自1982年以来,10年 Larix Principis-ruppre-chtii Mayr of Larix principis-rupprechtii has become the main afforestation species in Longdong area due to its rapid growth, straight stem, good material, cold tolerance, drought tolerance and adaptability. It has been developed only in the Ziwuling area More than 10,000 acres, the state-owned forest forestry total field has created 25,000 mu. However, due to the constraints of natural conditions (less rainfall, drought, frost, high temperature), seedling more difficult, seriously affecting the development of Larix principis-rupprechtii. State-owned Forestry Corps total field since 1982, 10 years