Physical attenuation effects of forest spaces on noises

Abstract

used a sound test to determine the physical attenuation effects of forest spaces on noises. We selected a 10(cid:186)50 m study area in a deciduous broad-leaved forest in Ohmi District, Sakyo-ku, Kyoto City. Oscillating sound was sampled at 80 and 95 dBs, and the sampling frequency comprised nine patterns : eight sine waves（125, 250, 500, 1,000, 2,000, 4,000, 5,000 and 8,000 Hz）,and white noise. The sounds were oscillated from a set oscillation point and recorded at the heights of 1.3 and 5.0 m at five sound recording points. The sound pressure levels of the recorded sounds were then analyzed. A sound test was performed twice: before and after the falling of leaves. We created a standing tree map and a crown projection diagram based on tree census data, calculated the volume of the space occupied by the branches and leaves in the tree crowns, and established the presence and absence of leaves. The differences between the measured and theoretical values of sound-pressure levels（hereinafter, the