Biology Reference
In-Depth Information
recent investigation Fan et al. (
2010
) evaluated the level of noise absorption by six
species of evergreen plants: arrowwood (
Viburnum odoratissimum
), oleander
(
Nerium indicum
), Chinese photinia (
Photinia serrulata
), bamboo (
Oligostachyum
lubricum
), red robin photinia (
Photinia fraseri
), and deodar cedar (
Cedrus deo-
dara
). Every plant has demonstrated a specific spectrum response. The amount of
noise reduction depends not only on the single plant species but also by the
arrangement of different species according to the environmental noise specificity.
These authors have presented some useful suggestions such as use of species that
have a more similar noise reduction spectrum to environmental noise, and combin-
ing of different species is possible to improve the attenuation effect. They have
found that deodar cedar reduces the low-frequency noise much better than the other
five species considered and that some characters, such as leaf shape, leaf weight,
and leaf tactility affect directly the noise attenuation value. Attenuation peaks are
performed by the species but their arrangement is the major factor responsible for
degree of attenuation.
10.16 Design the Soundscape of Urban Spaces and Parks
In urban planning sound was considered at the end of the projects, when structures
and open spaces had been built, but in a new perspective sound should receive at
least the same score of visual esthetics components because the soundscape
contributes to the identity and specificity of this urban environment.
The acoustic design represents an important activity to improve sonic environ-
ment in urban spaces. High-frequency music and waterfalls of fountains can
adequately mask traffic noise, transforming open spaces into a comfortable dimen-
sion. The inclusion of greenery in the urban context creates natural barriers to traffic
noise and adds songs from birds and insects. In some cases playbacks by
loudspeakers have been used to imitate natural sounds.
Designing a quiet area does not mean to exclude every sound; a natural quiet
soundscape refers not to silence but to the presence of natural sound sources.
Components of the natural quiet include the wind blowing through a forest, the
babble of water in a stream, the howl of a wolf pack, the chirp of a bird, the rumble
of an avalanche, thunder and a rainstorm, the crash of ocean waves, and the
deafening roar of a waterfall, although in a urban context some sounds of the
wild cannot be present.
The benefits of a good urban park to extend environmental benefits to the largest
part of the population possible have created great interest in policymakers and
decision makers. The majority of park design is based on visual components such as
shape and position of vegetation, but a peaceful quiet place is characterized also by
a comfortable sonic ambience. For this reason the soundscape is an important factor
to rate the quality of an urban park. The sonic environment is the result of the
contribution of many different types of sounds that occur either contemporarily or
separately in time. For instance, bird twittering or falling water are pleasant sounds
while mechanical sounds are considered unpleasant and not welcome in a urban
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