Study On Noise Reduction Function And Benefit In Different Types Of Road Protection Forest

This paper used road protection forest as research object,the test of noise reduction and spectrum analysis was used to explore the traffic noise attenuation effect and frequency characteristics of different types road protection forest.The regression model of noise attenuation of road protection forest was established.And the evaluation method of noise reduction effects of protection forest was studied. The theoretical basis and technical support for the planning, design and evaluation of traffic protection forest was provided. The research conclusions are as follows:(1)Ranking of the additional noise reduction of different types road protection forest(in wide 60m): mixed broadleaf-conifer forest > Ilex chinensis > Prunus lannesiana > Cedrus deodara>Prunus cerasifera>Zelkova schneideriana.(2) The additional noise reduction of protection forest was increasing while the mean surface density of protection forest was increasing. And the linear regression equation was: , R~2=0.877. Additional noise reduction was related to the mean surface density, which was at the 0.01 level significant correlation. The mean surface density of protection forest was an important factors that effect the noise reduction.(3) The regression equation of the additional noise reduction of protection forest is as follows: , R~2=0.936. The root mean square error of the regression model was less than 4.3%, so it achieved the expected accuracy.(4)The additional noise reduction of different types road protection forest in the frequency of 500 Hz was at the peak.Effect of mixed broadleaf-conifer forest traffic noise reduction was the best.Mixed broadleaf-conifer forest, Prunus cerasifera,Zelkova schneideriana and Prunus lannesiana should be applied when the forest wide was 20m(in 500Hz). Mixed broadleaf-conifer forest,Prunus lannesiana and Cedrus deodara should be applied when the forest wide was 40m(in 500Hz). Mixed broadleaf-conifer forest,Ilex chinensis,Prunus lannesiana and Cedrus deodara should be applied when the forest wide was 60m(in 500Hz).(5)Using equivalent replacement method respectively to the G312(K312+540m~K313+170m) south needle mixed broadleaf-conifer forest noise reduction efficiency evaluation. The result was 100000 yuan/(hm~2·a).