在“三北”防护林体系建设中,有四大防护林种。其中有关农田防护林的建设和营造技术,在东北西部、内蒙东部、黄河河套、河西走廊、新疆绿洲等地区都有一整套的经验和实施方法。但对水土保持林,防风固沙林,牧场 In the “Three Norths” shelterbelt system, there are four major types of shelterbelt. Among them, the construction and construction techniques of farmland shelterbelts have a complete set of experience and implementation methods in western Northeast China, eastern Inner Mongolia, the Yellow River Loop, the Hexi Corridor and Xinjiang Oasis. However, soil and water conservation forests, sand-fixing forests, pastures