NOISE REDUCTION BY VEGETATION AND GROUND - WITH DISCUSSION

EXPERIMENTS WERE CONDUCTED ON MEASURING THE LOSS OF NOISE TRANSMISSION FOR PLOTS OF (1) DENSE CORN, (2) DENSE HEMLOCK, (3) OPEN PINE, (4) DENSE HARDWOOD BRUSH, AND (5) OVER SOIL. WIND VELOCITY AND TEMPERATURE GRADIENTS WERE RECORDED. COMPARISONS ARE PRESENTED ON EXCESS ATTENUATION OBTAINED FOR UNITS OF DECIBELS/100 FT: THE CORN CROP HAS AN EXCESS ATTENUATION OF 6 DB/100 FT. FOR EACH DOUBLING OF FREQUENCY BETWEEN 500 AND 4000 HZ. THE STEMS OF THE HEMLOCK, PINE, AND BRUSH ALL REDUCED NOISE BY ONLY ABOUT 5 DB/100 FT. AT 4000 HZ. BARE GROUND ATTENUATES FREQUENCIES OF 200-1000 HZ, AND THE FREQUENCY OF MAXIMUM ATTENUATION DEPENDS ON THE SOIL PERMEABILITY TO AIR. THUS, TILLING THE SOIL REDUCED THE FREQUENCY OF PEAK ATTENUATION FROM 700 TO 350 HZ AND INCREASED MAXIMUM ATTENUATION AT 52 M FROM THE SOURCE BY NEARLY 80%. IN CONCLUSION, IT IS SUGGESTED THAT BANDS OF VEGETATION BE USED TO REDUCE NOISE. /AUTHOR/

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  • Accession Number: 00205213
  • Record Type: Publication
  • Report/Paper Numbers: No 1 Pt 2
  • Files: TRIS
  • Created Date: Apr 8 1973 12:00AM