“森林型生态城市”能速成?

近几年来,一些大城市继“草坪热”之后,又刮起了“大树”移植风——从农村和山区购买现成的“大树”移植进市区。不少城市都拟订好了规划,有的要实施“万棵大树移植工程”,有的要消灭“城区內无大树的历史”。有个城市。

A Comparative Study on Pattern of Urban Forest Patch and Its Ecological Benefit Evaluation in the Park of Hefei Based on the GIS Technology

Based on the GIS technology, CITYgreen computer model was used in this paper to estimate ecological benefits of urban forest in the park of Hefei city.It used this technology to make an analysis on urban forest ecological benefits. The research discussed how to use the technology of CITYgreen model developed in USA to account urban forest benefits in China. The results showed that forests in Xiaoyao Jin Park occupied about 52.62% of park land area and Xinghua Park13.00% respectively, indicating that Xiaoyaojin Park is dominated by large trees such as arbors, and Xinghua Park dominated by laws, with low coverage. Besides,the comprehensive eco-benefits of Xiaoyaojin Park and Xinghua Park were 5.150 3and 1.354 3 million yuan and per unit area eco-benefits were 144 000 and 47 400yuan/hm^2, which indicated that Xiaoyaojin Park makes the greatest contribution in ecological benefits.

“大树进城”反映浮躁心态

我国一些城市在绿化中继"草坪热"之后又刮起了一股"大树移植风".此风从上海刮起,迅速蔓延全国.当时就有许多园林专家呼吁刹住此风,但几年过去,此风反而愈刮愈烈.近几天又听到两则消息,一是大连将耗资2亿元"邀请"50万株大树进城,建设"森林型生态城市"(2002年10月28日<京华时报>);二是浙江余姚从广西、江西、安徽、湖南等地购买了500余株树龄在100-400余年的古树用来装扮城市(2002年12月8日中央人民广播电台<今日中国>报道).从移植大树发展到搬运古树,这种现象实在令人担忧.

古树名木为何“背井离乡”

建设“森林型生态城市”是发达国家20世纪60年代提出的主张,其目 的是呼唤人与自然和谐相处。1998年以来,上海、浙江、广东等一些大城市也相继走建设“森林型生态城市”这条路,借鉴新加坡等国的“成功经验”,纷纷加快城市绿化步伐,移植了数量可观的大树、古树进城。随即,很多大中城市争相效仿,大江南北刮起了一阵“大树进城风”,且愈刮愈烈。“大树进城”,究竟算一种什么样的“绿化”?它给生态环境建设带来的是什么?