英國冬青灌叢林之減音效果

The Effectiveness of Noise Reduction by the Shrubbery of Holly (flex aquifolium)

本文旨在探討灌叢樹林的減音效應，以大面積的英國冬青純林篦材料，在不同樣區播放人工音源，以樹林深度及以可見度為變項，測量噪音在樹林中的衰減趨勢。樹林的衰減效果與距離呈現對數單調遞減的趨勢，離音源越遠衰減效果越好。樹林可見度越小，減音效果越佳，將聲音減低至背景偵所需的距離越小，可見度I.Im的樹林需22m深之距離，可見度3.4m的樹林需29m的深度，可見度7-ISm的樹林需37-50m。扣除距離效應之後，前20m的穿透損失效果最良好，25m-40m處的樹林次之，大於40m處的樹林最差。整合樹林可見度及深度等變項，提出噪音衰減的回歸方程式。最後以疊圖法求出樹林的減音效益分佈，具體提供有效的植栽減音建議。

The purpose of this study was to experimentally determine th e attenuation characteristics of noise for vegetation. The parametric study o f noise control was presented by /lex aquifolium. Th e experiment was performed by varying parameters ofvisibility(densess) and depth of plant. From the results ofth e experiment, by changing distance, three regions in th e attenuation could be found. The best effect of forest depth was o- 20m, the second 25-40111 and 45-50111 the third. The ower the visibility, the better the effect of noise abatement. This study also set up a regressive equation by the variable of visibility and the depth of shrub Finally, a map of the effect of noise reduction was also constructed.