how can the architect design efficient landscape considering the local climate and the surrounding environment

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I Case studies
By: Mohamad Diab
Head of design
Energy City Qatar (ECQ)
Sustainable landscape
architecture
Efficient residential garden
Architect Mohamad Diab is the head of the design department
in Energy City Qatar (ECQ). He has held key positions in several
companies delivering a variety of project types in different sectors of
the design and the construction industry.
Diab has obtained a Master degree in architecture and has more
than 20 years of extensive experience in projects Management and
development, Urban Planning, Architectural and Landscaping projects.
His background lies in green building rating systems and he’s a
GSAS Certified Green Professional (CGP) and LEED Green Associate
accredited, as well as being an active member in QGBC and LGBC.
What is Sustainability?
Sustainability is a socio-ecological system process that reduces the negative
human impact which causes harm to the environment and further enhances
the microclimate and development efficiency and performance.
A microclimate refers to atmospheric zone conditions that surround the
building and the term may refer to areas as small as a couple of metres
squared such as private gardens. Microclimate conditions include sun
intensity and duration, soil quality, rainfall, air circulation and temperature.
Sustainable development
Sustainable landscape accounts for the following principles - environmental,
social and economical. The natural factors and site conditions should
be measured from the early design stage with high consideration for the
climate conditions in the region such as temperature, air pressure, humidity,
Imagesdrawnby:ArchitectMalakFarhat

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The First Specialised Landscape Magazine in the Middle East
precipitation distribution, sun path with the building orientation and seasonal
wind pattern. The landscaping elements should be incorporated with the
architectural building design in order to obtain the optimal design efficiency
and higher rating for the green building system. In other words it is necessary
to blend the art into man’s technology to create a functional, aesthetically
pleasing extension of indoor living to the outdoors.
Intelligent landscaping design can essentially enhance the building energy
efficiency. Simple considerations when landscaping the home and property
can make a big difference in the individual comfort and the efficiency of
heating and cooling systems. So what are the necessary implementations
and requirements to achieve the efficient landscape? Here are some factors
to consider. During landscape design preparation, an essential consideration
should be given to proper placement and selection of plant species to create
a stunning and efficient landscape and increase the property value and visual
enhancement as well. Plants should be selected on the basis of mature size.
The effective plants impact require identifying the size, shape, density and
location that can first minimise building energy consumption during summer
days by reducing heat absorption in shading and then protect the house from
the harsh wind in winter, especially plant windbreak. In general the shading and
windbreak terms are achieved and reflected respectively by the two main plant
categories - deciduous and coniferous.
Deciduous trees
Deciduous tree is a plant life form that responds to an unfavorable season
by shedding its leaves. The best placement of plant deciduous trees is on
the southeast, south and southwest sides to shade the building and to reduce
reflectivity of hardscape surfaces, building walls and roof-tops.
Effective deciduous tree placement
Maximum cooling savings and energy conservation of deciduous trees with
high, spreading crowns are planted to shade the southern walls in summer.
They keep the summer breeze passing through the trees (Figure 01).
Consequentially, such trees can have a cooling effect and reduce the air-
conditioning demand if used for natural home ventilation.
Figure 1
When the trees lose their leaves during winter, the deciduous trees permits
the natural sunlight to pass through the tree trunks and twigs therefore solar
heat may reach the windows (Figure 02). As such, this would enhance the
building heating system and decrease the fossil fuel consumption required for
heating. Trees with crowns lower to the ground are more appropriate to the west,
where shade is needed from lower afternoon sun angles. Large trees with dense
leaf growth provide welcome relief from the hot summer sun when positioned
between the roof of the home and the angle of the sun at midday and afternoon.
Figure 4
Coniferous trees
Coniferous trees are typically evergreen and retain its needles
year-round and require less water. They can inhabit in arid areas.
Coniferous trees have a variety of benefits- they are more watertight
and windproof.
Effective Coniferous Tree placement
Properly selected, placed, and maintained evergreen plants can
provide excellent wind protection which will reduce heating costs
considerably. High trunk conifers trees can be planted at the south
façade if there is an important view, the high trunk does not obstruct
the sight during the year. The canopy will provide shading on the roof
and façade and allow the summer breeze to cool the house during
summer months (Figure 03). In winter, the low sunlight angle will
reach the windows below the crown enhancing the house heating
efficiency (Figure 04).
Figure 3
Figure 5
Evergreen trees and shrubs planted to the north of homes are the
most common type of windbreak (Figure 05) that shelters homes
from heavy winter winds. Trees and bushes are often planted
together to obstruct the wind from ground level upwards and deflect
or lift the wind over homes. To use a windbreak effectively, plant
dense evergreen trees or shrubs to provide continuous shade the
year-round where needed. Windbreaks also provide barrier from
unwanted noise (Figure 06), dust and smells. Screen unsightly
views and provide privacy.
Figure 2 Figure 6

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How can the sustainable garden influence the development?
Reduces the urban heat island effect and minimize effects on
microclimates.
Mitigates the temperature transmission between inside and outside
and keeps the building warmer during winter and cooler during
summer.
Wind control. Using buffer plantings to create wind screens (blocks
harsh winter wind, direct rainfall, sandstorm, dust control and
intensifies the summer breeze).
Water quality protection. Filters pollution and reduces storm water
runoff.
Air Purification. Improves air quality by absorbing the carbon dioxide
emissions.
Soil protection. Controls the soil erosion caused by wind or storm
water runoff.
Sound insulation. Plants absorb, reflect and diffract noise.
Enhances the residents’ physical and mental health by creating safer
pedestrian-friendly environments.
Reduces the negative effects of sunlight reflection and glare.
Increases the social value of space.
Design principles
The landscaping elements can be physically described by the visual
qualities consisting line, shape, colour, size and texture. Some
general principles of composition that apply to planting design are
- proportion, symmetry, hierarchy, order, repetition, balance and
harmony and all serve as guidelines to assemble and organize the
features to create an esthetically pleasing or beautiful landscape.
In general, plants are organized and classified into families, genera,
varieties, etc. This, however, is not the only basis of classification.
Species can be grouped into life or growth-form categories such as:
Form: Upright, prostrate, horizontal and spreading, rounded, vase-
shaped, pyramidal.
Texture: fine/coarse, light/shade, heavy/light, thin/dense.
Colour ( foliage, flowers or fruits).
Consequently, what are the functional aspects of landscaping design
to be measured in terms of efficiency? Let us conclude with some
recommendations:
Minimise the grass amount that requires lots of watering and replace it
with the artificial mulch or gravel ground cover, to reduce evaporation
and soil erosion.
To reduce the required water consumption, use the native plants that
have adapted to the area’s climate conditions and soil.
Views should be identified and preserved by avoiding planting trees
that can block the attractive sightlines in front of windows.
Surrounding distractions must be identified such as noise, glare or
odors.
Minimizing the copious irrigation usage, adopting more efficient
watering techniques when necessary such as drip or spot irrigation.