City trees and municipal Wi-Fi networks: Compatibility or conflict?

Abstract

Conflict between city trees and infrastructure remains a problem in urban forestry. Municipal Wi-Fi, a city- wide wireless computer network, may become a part of urban infrastructure, and because trees can diminish Wi-Fi signals, potential exists for conflict between urban trees and municipal Wi-Fi. This study examines attenuation of Wi-Fi signals in the City of Mountain View, California, U.S. by positioning a wireless-equipped computerso that trees obstructed the line-of-sight (LOS) between the computer and a Wi-Fiaccess point. Signal attenuation ranged from > 2 dB to 19 dB (mean: 5.6 dB),depending on the number and types of trees present. Although trees significantlyattenuated signals, they did not diminish the average signal strength below -75 dBm (the minimum for a Wi-Fi connection) in any of the tests. A general linear model (r2 = 0.55) indicated that some tree characteristics (tree size, canopy depth,leaf type), but not others (number of trees in LOS, presence of leaves, leaf size, adshape) helped explain variation in signal attenuation. Aslong as the effect of urbantreesis taken into account during planning of Wi-Fi networks, trees should notinterfere with municipal Wi-Fi peration. © 2009 International Society of Arboriculture.