北京平原地区公路典型绿化带降噪功能初探

Study on Noise Attenuation of Green Belts in Plain Area

[目的]选取京开高速绿化带为研究对象,定量分析交通噪声在水平空间上的衰减规律,同时探讨绿化带的宽度、群落结构对交通噪声衰减的影响,以期为平原地区高速公路绿化带的树种选择、结构优化以及修剪管理提供一定的理论依据。[方法]选择3种典型林带类型的绿化带,建立9个20 m×60 m的样地,并在每个样地内按垂直于高速公路的方向设置不同宽度梯度的监测点,在定点连续监测的基础上,采用单因素方差分析(ANOVA)探讨不同林带类型、不同宽度梯度之间噪声值的差异性,采用Pearson相关分析探讨绿化带结构指标和绿化衰减系数之间的相关性。[结果]表明:研究选取的3种类型绿化带的降噪功能均较好,雪松纯林的降噪能力最强。绿化带在0 10m的范围内降噪能力最强,随着宽度的增加,绿化带的降噪能力逐渐减弱。绿化带的降噪能力是由多个林分结构指标协同作用的结果,并不能仅用某一结构指标表征整个群落的降噪能力,绿化带在同一高度水平上的断面积是影响其降噪能力的一个重要综合指标。[结论]高速公路绿化带可以起到良好的降噪功能,不同林带类型绿化带的降噪能力不同。在建植时,应优先选分枝点低、分枝多、枝叶细密的植物。在城市绿地空间不足的情况下,为完全消除交通噪声对居民生活的影响,还应辅助于其它技术措施。

Taking the green belts of Jingkai highway as sampling site to analyze the traffic noise attenuation characteristics in horizontal space and to study the impact of width and community structure of green belts on traffic noise attenuation, so as to provide some references for optimizing the vegetation structure of green belts as well as programming and construction of green belts. [Method]Three typical forest types were chosen, and 9 sample plots （20m×60m） were established. At each plot, the monitoring sites were set up in different width gradient perpendicular to the direction of the highway. Based on continuous monitoring, the difference among various forest types and width gradient were analyzed by using the one-way ANOVA. Pearson correlation coefficient was used to analyze the relationship between community structural indexes and noise attenuation. [Result]All the three types of green belts show certain functions of noise reduction, and the functions of Cedrus deodara pure forest are the best. The optimal width of green belts to reduce noise should be 0~10 m in the selected greening modes, with the increasing of width, the ability of noise reduction gradually declines. The ability of noise reduction is composed of multiple community structural indexes, while an indivial structure index could not represent the noise reduction ability. The sectional area of green belt in same height is an important indicator affecting the noise reduction ability. [Conclusion]The green belts of highway could play an important role in noise reduction. Different forest types of green belts have different ability of noise reduction. When establishing green belts, it is better to chose the species with low branching points, more branches of fine and dense. In the case of insufficient urban green space, other technical measures should be assisted to completely eliminate the influence of traffic noise on residents＇ life.