NOISE REDUCTION BY VEGETATION AND GROUND
TRANSMISSION OF RANDOM NOISE THROUGH DENSE CORN, A DENSE HEMLOCK PLANTATION, AN OPEN PINE STAND, AND DENSE HARDWOOD BRUSH, AS WELL AS OVER CULTIVATED SOIL, WAS MEASURED. THE RELATION BETWEEN ATTENUATION AND FREQUENCY IN THESE DIVERSE CASES SUGGESTED MODELS THAT PERMIT THE PREDICTION OF ATTENUATION IN ANY CONFIGURATION OF VEGETATION AND SOIL. THE CORN CROP HAD AN EXCESS ATTENUATION OF 6 DB/100 FT FOR EACH DOUBLING OF FREQUENCY BETWEEN 500 AND 4000 HZ. ON THE OTHER HAND, 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%. FURTHERMORE, EARLIER CONFLICTING REPORTS OF NOISE ATTENUATION BY VEGETATION APPEAR RECONCILED IF GROUND ATTENUATION IS TAKEN INTO ACCOUNT. SCATTERING AND GROUND ATTENUATION ARE THE PRINCIPAL FACTORS IN SOUND ATTENUATION BY VEGETATION. BOTH FACTORS ATTENUATE RELATIVELY LESS SOUND AS DISTANCE FROM THE SOUND SOURCE INCREASES. HENCE MEASUREMENTS FAR FROM THE SOURCE CAN UNDERESTIMATE THE EFFECT OF A NARROW BAND OF VEGETATION OR SOIL /AUTHOR/
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Availability:
- Find a library where document is available. Order URL: http://worldcat.org/issn/00014966
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Supplemental Notes:
- Vol 51, No 1, PART 2, PP 197-205
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Authors:
- Aylor, D
- Publication Date: 1972-1
Media Info
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Serial:
- Journal of the Acoustical Society of America
- Publisher: Acoustical Society of America
- ISSN: 0001-4966
- Serial URL: http://asadl.org/jasa/
Subject/Index Terms
- TRT Terms: Ground cover; Noise; Noise control; Sound absorption; Vegetation
- Uncontrolled Terms: Attenuation
- Subject Areas: Environment; Highways; Safety and Human Factors;
Filing Info
- Accession Number: 00223705
- Record Type: Publication
- Files: TRIS
- Created Date: Mar 20 1972 12:00AM