中文摘要：

本文采用对比研究的方法,对中美城市树木的碳储存和碳封存状况进行比较,结果显示我国的主要城市树木平均碳储量高于美国,单位面积碳储量平均值低于美国,揭示了研究城市树木的碳储存和碳封存具有重要的现实意义,为我国进一步提升城市的生态环境以及城市树木的种植提供了有益思路。本文建议：在进行城市树木补植补造的同时,重视树木种类的选择和气候条件;加大城市绿化的投入力度,加强植被复层结构的管理;加强体制和机制的建设,关注城市树木的种植和养护。

英文摘要：

In this paper,the carbon storage and carbon sequestration of green land in urban areas of China and the United States were studied by using comparative method. The results showed that the average carbon storage of the main urban in China was higher than that in the United States,but the average carbon storage per unit area was lower than that of the United States. The paper also revealed the significance of carbon storage and carbon sequestration of urban forest,which provided a useful way to improve the ecological environment of the cities and the cultivation of urban trees in China. Some suggestions were put forward. Firstly,more attention should be paid to the selection of tree species and climate conditions in further replanting. Secondly,the investment in urban greening should be increased and the management on vegetation layer structure should be enhanced. Finally,the system and mechanism construction should be strengthened and attention should be paid to the planting and maintenance of urban trees.