EFFECT OF SHADE-TREES PLANTATIONS ON THE NOISE LEVEL OF URBANIZED TERRITORIES
It is pointed out that the high rate of noise pollution associated with increased transport flow requires the finding of optimal ways to reduce the noise level. The purpose of the research was to study the ability of shade-tree plantations to noise suppression. The objects of the study were trees-and bush plantations and the levels of noise along the traffic flow in the vicinity of public and residential buildings. When comparing the data obtained on the noise level with the sanitary standards including 19 measurements, only 9 of them are corresponding to the equivalent and the maximum standard levels, while in 10 cases an excess of the permissible noise pressure has been observed. In the process of studies it was found that most often the distance between the trees is at 1.5-2 m less than it is required by the corresponding building norms and regulations. Many tree-plantation belts are located, on the average, at 1 m nearer to the public roads. As shown by a comparison of the various tree plantation characteristics the mixed tree stands which consist of multiple tiers have the most significant noise protection capability. Higher rates of noise protection can be achieved by the combination of such tree stands factors as storiness of plantations, crown density, the width and average height of the tree stand, although they are not equivalent as to this ability. There has not been found any distinct advantages of one type of tree plantations over the other, but it was observed that plantations including several tree species were significantly more effective than those consisting of single tree species.