Tree stands in urban noise abatement

Abstract

The aim of the paper was to study the characteristics of tree stands suitable for urban noise control and their application in urban forestry. The results show: that excess noise attenuation caused by trees can be, under good conditions, 60% of the attenuation caused purely by geometric spreading when attenuation is expressed in energy units; that the total amount of needles or leaves is the most important factor, although the density and height of the stand also have rather high values in predicting the behavior of noise in a tree stand; that the noise level at any distance from the noise source can be predicted rather precisely, if the sound level of the noise source and the tree species composition, height and density of the tree stands between the noise source and the observation point are known; and that early successional stages of stand give better attenuation than mature stands. On the basis of these results the nomograms were developed with which the noise level at a certain point can be predicted when the tree stand characteristics, the distance from the noise source and the sound level of the noise source are known and vice versa. The goals of urban forestry are discussed based on different functions that urban forestism must fulfill.