城市绿地彩叶树种观赏价值综合评价与分级

为解决城市绿地景观色彩单调、彩叶植物配置不合理等问题,在详细调查兰州市城市绿地彩叶树种资源的基础上,以兰州市近年来主要利用的21种彩叶树种为研究对象,对其的观赏特性及生态习性进行详细的观察与记录。同时选择13个重要评价因子,建立城市绿地彩叶树种综合评价模型,采用层次分析法进行观赏价值综合评价,并根据评价结果对其进行观赏等级划分,结果表明:(1)在13个评价因子中耐寒性、呈彩期、耐旱性和抗病虫害对观赏价值的贡献率较大。(2)综合评价等级分为3个等级,Ⅰ级(M≥80%),观赏价值高的种类,共计4种;Ⅱ级(79%≥M≥60%),观赏价值较高的种类,共计13种;Ⅲ级(M≤59%)观赏价值一般的种类,共计4种。(3)Ⅰ级的种类建议作为兰州市城市绿地规划的首选物种,Ⅱ级的种类建议在城市绿地规划中大量使用,Ⅲ级的种类建议根据实地情况,在特定条件下选用。

Comprehensive Evaluation and Classification of Ornamental Value of Colored-leaf Tree Species in Urban Green Space

In order to obtain new poplar varieties suitable for Jianghan Plain in the middle and lower reaches of the Yangtze River, different varieties of black poplar used as parents were selected to hybrid. The growth traits and genetic parameters, such as phenotypic coefficient of variation, genetic coefficient of variation and repeatability, were determined and analyzed at the seedling stage of F1 hybrid progenies. The results showed that Fl generation showed obvious hybrid vigor. The variation range of seedling height and ground diameter was 2.9-5.7 m and 13.5-52.0 mm, respectively. The repeatability of seedling height and ground diameter was 16.7%-56.3% and 30.7%-64.7%, respectively, while the repeatability of ground diameter was higher than that of the seedling height in the same hybridized combination. A total of 234 clones from 6 cross combinations were selected through comprehensive evaluation. Average genetic gain of seedling height and ground diameter of selected clones were 6.7% and 10.8%, respectively, which meant they could be applied to comparative evaluation in the comparative experiment of field afforestation in the future.