The implication of green area in ur

The implication of green area in urban form
The causes of Urban Heat Island (UHI) are heat stress and other effects triggered by the densely built
environment when the natural landscapes are with buildings and roads. The microclimate condition has
significant impacts on urban occupants, as the higher temperature in cities will result in increased energy
use for indoor and cooling and higher water demand for landscape mitigation. The high humidity in
tropical cities combined with high air temperature will create discomfort and undermine the function of
outdoor places. As a result, the demand for a better microclimate condition is more pronounced today
than decades ago. Shading from trees has proven to improve the condition of human energy heat balance
while doing outdoor activities and improve the indoor conditions of building by reducing the solar
radiation on the building facades. Previous studies (Akbari, Pomerantz, & Taha, 2001; Mohd Fairuz
Shahidan, Jones, Gwilliam, & Salleh, 2012) have verified that the density of the tree crown would reduce
the air temperature under the tree between 2 and 4 °C. When the UHI effect is correlated with the trees
density, the result showed that a significant value of green area or vice versa (Chow & Brazel, 2012;
Gago, Roldan, Pacheco-Torres, & Ordóñez, 2013). Besides energy consideration, high temperatures could
increase health risks and atmospheric pollution, as it is known that the greenhouse effect contributes
towards global warming, higher energy demand and emission. Hence, the urban green areas and
infrastructure should be maintained in tropical hot and humid cities to guarantee the well-being of the
urban communities (Mansor, Said, & Mohamad, 2010).
Therefore, the strategies of planting more vegetation in urban areas are used to alleviate the
greenhouse effect since vegetation plays a significant role in regulating the urban climate. In a hot
climate, vegetation planted around buildings can alter the energy balance as well as cooling energy
requirements of buildings by sheltering windows, walls, and rooftop from strong solar radiation as well as

radiation reflected from the surroundings. Trees could help reduce the CO2 level, increase O2 and the
quality of life (Borhan, Ahmed, & Hitam, 2013).