北京市中心城区行道树结构的研究

Study on structure of street trees in central districts of Beijing

通过分层随机取样,对北京市中心城区行道树种类构成、应用频度、多样性指数、径阶结构、树高组成及季相结构进行研究。结果表明:北京市中心城区行道树共有13科21种,其中常绿与落叶的比例为24︰1;行道树种类丰富度较高,但分布不均匀;新城区在行道树树种丰富度上总体要高于老城区;行道树径阶结构分布上,老城区偏大,新城区则偏小;在行道树树高方面,二者差异不明显;中心城区行道树在季相结构上,以夏、秋为主,春季景观较薄弱。根据北京市现状,采取引入新品种、控制树种搭配等改进措施,可以缓解行道树绿化当前存在的问题。

Through stratified random sampling to the 142 transects, the structure of street trees in central districts of Beijing, differences in species composition, application frequency, diversity index,structure of DBH（Diameter at breast height）,composition of the tree height and aspection characters were investigated. The results show that the street trees in central districts can be classified in 21 kinds of 13 families, the ratio between deciduous and evergreen trees was 24︰1;the street trees possessed comparatively high species richness, but didn’t evenly distributed;the old districts had a lower diversity compared to the new districts;the distribution of DBH structure of the street trees in old district was relatively larger and the new district was smaller;the composition of the tree height between them had no significant difference;Taking account of seasonal phenomena structure, the street trees in the central districts displayed mainly with summer aspection and fall aspection and the spring landscape appeared relatively weak. These results highlight the needs to introduce new varieties of street trees, and to select an appropriate and diverse mix of deciduous and evergreen tree species for new planting.