三十多年来,北京的园林树木不仅数量增多,种类也不断丰富。由于北京气候等条件的限制,常绿树木种类较少,绝大多数为落叶树种。落叶后树木的冬态不太容易识别。而许多园林工作如起苗、假植、出圃,春季植树,冬季树木的修剪等常在落叶后展叶前进行,因此 For more than three decades, not only the number of garden trees in Beijing has increased, but the species has been continuously enriched. Due to the restrictions of Beijing’s climate and other conditions, the evergreen trees are rare and the vast majority are deciduous trees. Deciduous tree winter is not easy to identify. Many garden works, such as raising seedlings, fake plants, nurseries, tree planting in spring and pruning of winter trees, are often carried out before the leaf-setting leaves. Therefore,