Show S T I II I J t 1 lj i Jt t 4 i y i f J L I L S Quiet Pleases And Nature Has To Help It Happen If you dont don't have teen teen- teenagers teenagers agers around the house playing their rock music at its loudest possible volume you may think you are es- es escaping escaping caping today's sound pol- pol pollution pollution lution dangers Not so Granted the noise lev lev- lev level el most ost adolescents seem to require from their music may be a threat to an adults adult's sanity and physical well being but Information compiled by the green sur- sur survival survival vival people in the Amerl- Amerl Amen CM can Association of Nur- Nur Nurserymen Nurserymen indicates the nor nor- normal normal mal day day to-day cacophony around us can cause serious seri seri- serious ous damage without our realizing it For example In a re- re recent recent cent test involving two pairs of laboratory mon mon- monkeys monkeys keys on one pair was placed in ina ina a quiet the environment other listened continuously for nine months to record record- recordings recordings ings of the sounds many workers are subjected to daily The blood pressure of the noise exposed mon mon- monkeys monkeys keys quickly rose 25 per per- perc pert c nt higher than that of the monkeys living a quiet life Acoustical engineers know that lining a room with spongy wall boards 0 ox thick draperies can reduce the sound level drastically In- In Instead instead stead of having the sound waves bounce off hard sur- sur surfaces surfaces faces the loose fibres a ab- ab absorb b- b and deaden them By the same process the myriad surfaces of lof stems and foliage of trees and shrubs bs accomplish a similar beneficial silencing effect out of doors The first work with using screens of trees and shrubs for noise reduction was done in Germany to de de- de decrease crease the noise of highways which ran through residential residential areas Since then much work has been done by state and federal highway depart depart- departments ments in the US to de- de develop do optimal sound bar bar- barriers Noise reductions of six sixto sixto to eight decibels have been demonstrated with witha a foot wide belt of trees Human hearing begins to tobe tobe be damaged by exposure to more than 85 decibels of sound and heavy city traffic traffic fic measures 90 decibels It Itis Itis is apparent then that are a re- re reduction of six or eight deci- deci decibels bels in noise level can mean the difference between hearing hear hear- hearing ing health and danger Trees shrubs and grass growing in the yard of a residence accomplish the needed silencing service on a smaller scale scaler Coniferous evergreen trees perform somewhat better than deci- deci dious varieties the ones which shed their leaves in winter since the great num- num number number ber of needles work as sound screens all year Primitive man lived in a world with a very low noise level and survival often de- de depended depended on acute hearing St So our ears were simply not designed to the decibel level of the century environment Living plants are arc natures nature's way to help restore quiet quitt in n our O lives and quiet pleases I 1 |