过去的二十年间,美国已经营造了三千多万英亩的人工林和防风林。其中11%是直播的,但是大多数是用苗圃培育的裸根苗营造的。1954年阿伯特报道了美国森林苗圃中实行的这种培育法的作业情况。十二年之后,阿伯特和威廉逊报道了1955～1964年十年间苗圃育苗的主要变化。本文介绍了1974年收集的有关育苗技术的情况。 Over the past two decades, the United States has created more than 30 million acres of planted forests and windbreaks. 11% of them are live, but most are made from nude root nurseries grown nursery. In 1954 Abbott reported on the practice of this cultivation law, which is practiced in forest nurseries in the United States. Twelve years later, Abbott and Williamson reported on the major changes in nursery nurseries during the decade from 1955 to 1964. This article presents the 1974 collection of seedling technology.