Studies On The Noise Reduction Of Landscape Vegetation Types In Fuzhou City

Garden plants as an important part of urban construction. They can beautify the city, maintain the ecological balance of the city, and improve the urban environment. They also do great contribution in reducing urban noise pollution. In this paper, the test we set up" 田" shaped,7 m and 14 m measuring point, in the summer and autumn we researched within 7 large city parks in Fuzhou, and measured 7 different types of communities in 70 different plant communities to find out noise reduction capabilities. We also measured 7 different frequency noise and 7 kinds of structural characteristics of different types of plant communities. Factors were quantitatively measured and statistical analysis to explore the closely related plant noise impact factor. We reached the following conclusions:(1)Under white noise conditions in the summer and fall,7 kinds of plant communities of the average sound level A noise reduction capacity size:bamboo mixed evergreen broad-leaved forest> evergreen deciduous broad-leaved forests> evergreen broad-leaf forest> evergreen coniferous broad-leaved forest> coniferous evergreen forest> palm forest> coniferous evergreen broad-leaved forest of palm trees mixed forest, and noise reduction is better in summer than in autumn. Plant community noise reduction in the relative rate of 14m from the noise source is greater than 7m from the noise source.14m at an average A sound level of noise reduction capability up to 41.316%, which 5.467%more than 7m away from the noise source at the highest average sound level A noise reduction capability. Under the condition of equal distance, plant community noise reduction effect is superior to the control.;(2) Under the pink noise environment, this three plant communities noise reduction effect are better:Bamboo mixed evergreen broad-leaved forest, palm forest and evergreen broad-leaved forest. Under summer conditions at 14m from the noise source of these three types of average sound level A noise reduction capacity are 41.922%,38.533% and 37.669% respectively, under the conditions of autumn pitch noise source 14m at an average A sound level of noise reduction capabilities are 41.061%,36.715% and 35.854% respectively, noise reduction is better in summer than in autumn. Under the condition of equal distance, plant community noise reduction effect is superior to the control.As the distance increases, red noise reduction capability growth is greater than the white noise.(3) Best for brown noise reducing plant community is bamboo mixed evergreen broad-leaved forest. This type of community from the noise source 7m in the summer at an average A sound level of noise reduction ability is 31.792%,14m away from the noise source at the average sound level A noise reduction ability is 40.390%; fall away from a noise source 7m at the average sound level of noise reduction ability is 31.069%,14m away from the noise source at the average sound level a noise reduction ability is 38.537%. Under the condition of equal distance, plant community noise reduction effect is superior to the control.About average A levels, we compared pink and white noise reduction capability found that brown noise lowest average A levels noise reduction ability.(4)Community structure factors which effected white noise reduction capability greatest in proper order are bare land rate, coverage, average spacing, average DBH and average branch under high; Community structure factors which effected pink noise reduction capability greatest in proper order are coverage, bare land, average distance and average diameter; Community structure factors which effected brown noise reduction capability greatest in proper order are coverage, bare land, average distance and average diameter. The coverage and relative noise reduction capabilities are positively correlated while bare land, average spacing, average DBH and average branch under high are negatively correlated.(5)Tested 70 kinds of plant communities made noise peak at 6300 Hz, noise occurs in the valley at 500Hz and 8000Hz. Evergreen broad-leaved forest, coniferous evergreen broad-leaved forest of palm trees mixed forest, evergreen and deciduous broad-leaved forest, palm forest and Bamboo mixed evergreen broad-leaved forest showed another peak noise at 2000Hz.