城市植树新方法美国园艺家提出采用几株树集中一起栽的方法，能提高城市栽植树木的成活率，并使树木长势好。美国康奈尔大学园艺家巴次克认为，由于城市大量混凝土、沥青和稠密的人群使得树木和灌木丛的寿命降低，而且从外表上看，树栽完后显得单调不美。因此，他提出：保... New method of planting trees in the city American horticulturists proposed to use several trees together in a concentrated way to increase the survival rate of trees planted in urban areas and make the trees grow well. Bartz, a horticulturist at Cornell University in the United States, believes that the longevity of trees and bushes is diminished by the large amount of concrete, asphalt and crowds in the city. Therefore, he proposed: Paul ...