An investigation of sound attentuation by tree stands

The thesis had two main objectives: namely to provide information on the sound attenuating abilities of tree species of the lower mainland region of British Columbia and to ascertain what stand characteristics cause trees to attenuate sound. After an extensive literature review an experiment was designed to investigate sound attenuation in eighteen tree stands, comprised of four species, at three distances, for eight different sound frequencies. The exerimental work was done during the winter of 1969 and the summer of 1970. Prior to this the tree stands were enumerated and various tree parameters measured. No patterns could be found which significantly correlated the measured stand characteristics with the amount of sound attenuated. Little significant difference was found between the summer and winter attenuations and it was found that stands reacted independently of the season. Tables are presented in the Appendix showing the attenuations for each stand, at each distance and for each frequency. Mean values together with their standard deviations are given for all stands within a species. Suggestions are given for future work on this topic and the implications of the results on various design fields are discussed.Forestry, Faculty ofGraduat