VERTICAL GREENERY IN IRAN - Attitudes and Prospects. Case Study: City of Tehran.

 

Abstract

Tehran is a mega city on a world scale as well as the most polluted city in Iran with large missed green space areas during last century. The shortage of unoccupied lands by buildings and high rise construction has been caused vertical green technology to become the most effective way for implementing greening now. To guard against climate change and the destruction of nature, we must design with an ecological integrated global network; we need to study mega cities with special conditions. Vertical greenery includes green roofs, roof gardens, living walls and green facades. This article reveals the main problems of current vertical greenery in Tehran and offers some alternatives. Tehran has a special semi arid climate and disturbed urbanism. Currently there is the lack of law and codes for Vertical greenery.
Vertical greenery is one of the best strategies to mitigate environmental challenges that climate change manifests, like increased pollution and urban heat island effects. Moreover, some of the main benefits of vertical greenery are the creation of microclimates, storm water management, water filtration and quality improvement, and the preservation or creation of habitat and biodiversity in the urban context.
Planning for green roofs and living walls as important components of green development in urban planning, as well as guiding suitable policy, providing standards and supportive regulations with sufficient awareness can improve and develop vertical greenery in Tehran and throughout urban areas of Iran. We need to go towards a green infrastructure framework for Tehran bolstered by the research and experiments of others.

 

1- Introduction

Today, we are thinking about compensating for what we did through several centuries on this planet, fighting against nature and fighting against ourselves! Our environmental transgressions have been a global mistake; and we need a global strategy for the restoration of nature and the restoration of minds! Greenery has many different applications and today one of the best construction examples is vertical, vegetative growth. Vertical greenery isn’t a new approach to urban greenery; in fact precedents can be found from many years ago.  In most examples such as green roofs, they created by nature and self grow native plants were flourished on top of buildings or cover facades; Except some countries, the majority in northern and central Europe, like Switzerland, Norway, and Germany people designed and installed green roofs, primarily for the thermal function. 

Today other factors are considered beyond the thermal benefits of green skins; therefore constructing them is a selected and suggested way for achieving sustainable and ecological demands. Protecting the integrity between structural elements, preserving the original pattern of ecological systems, will help to establish and enhance the ecological processes and flows in the urban and suburban environment. [1]
Establishment and conservation of urban greenery is a substantial component in sustainable urban development. Natural environments and vegetation in cities contribute to maintaining wildlife, improving well‐being and moderating the impacts of human activities including global warming. The greening of cities has been traditionally managed through urban parks, green corridors, suburban gardens and street landscaping. [2]

 

  2- From Garden Cities to Semi Modern Cities: The story of missing urban green areas in Iran

Figure 1: Isfahan and its Gardens in Safavid’s period; a perfect exemplar of an Iranian garden city.  [4, P 90]

 

In the past, many of old Iranian cities like Isfahan, Shiraz and Tehran were garden cities and nature was not separate from urban areas. After the arrival of modernism and the growth urbanism, modern homes and high rise habitats replaced gardens. Fast growing populations and changes in life style contributed to the destruction of garden cities. Only a few of these gardens exist now, most in Isfahan, Shiraz and north of Tehran. Very similar to other aspects of Iranian modernization, this urban development process was incomplete and semi-modern cities with a superficial modernism were born.

The travelers who visited Isfahan in the sixteenth century were astonished by the extent of its greenery and intensive garden complexes. “Indeed, the  city seemed like a huge, smooth,  green  stain,  crossed  by  a  blue  line   -the  river-  in contrast  to  the  rocky background of the desert.”[3, P 35]
Tehran, the capital of and largest city in Iran, has experienced rapid growth especially in the past three decades. Tehran has more than 12 million inhabitants and despite all the efforts by responsible organizations to improve environmental condition, it is contaminated with various environmental pollutants; and its ecological structure has experienced numerous destructions. Recent development of parks and public green space has not been able to restore the city’s an ecological network fragmented as a result of unplanned and uncontrolled growth.
During the reign of Pahlavi II in the 1960’s, concurrent with the development of Tehran and subsequent population increase, public parks were built after the fashion of western parks. From these eras on, these parks replaced old gardens in Tehran and, as a result, traditional Iranian garden construction sank into oblivion. Now, after the Islamic revolution, the remnants of natural and manmade ecological patches (ancient gardens, modern parks, open spaces, hills, and boundary forests) are under constant pressure of destruction due to urban development and the scarcity of land in increasingly heavily built-up metropolitan areas. [5]

 

3- Vertical Greenery

3-1- Why vertical?

Vertical vegetation is vegetation growing on, or adjacent to, the unused sunlit exterior surfaces of buildings in cities. Vertical vegetation can improve the energy efficiency of the building on which it is installed mainly by insulating, shading and transpiring moisture from foliage and substrate. Several design parameters may affect the extent of the vertical vegetation's improvement of energy performance. Examples are choice of vegetation, growing medium geometry, north/south aspect and others.
Additional research suggests that the integration of vegetation within the building envelope is a sustainable design strategy for the built environment. Another incentive to focus on vertical vegetation is its potential to cover large surface areas of building walls that are otherwise not used. In the urban context most vertical surfaces are merely a maintenance challenge whereas if “greened” these surfaces can serve as cooling engines, air purifiers, carbon sinks and be pleasing to the eye at the same time.[6]

In recent years, sky rise greenery has come into vogue as green building certification moves into mainstream consciousness in major cities across the world. Much has been published about incorporating vegetation into urban planning [2] But why vertical? Aren't there other choices? While we don't take advantage of green spaces on lands correctly, why do we need to implement vertical green spaces that consume more time and money? Don't forget, the design and construction of vertical vegetated systems require sufficient skill, room for experimentation and finally: technology! In Iran we do not have ample resources; therefore can vertical greenery substitute a missed garden city?!

Figure 3: Self growing plants on a natural green roof, north of Iran

Urban parks have recreational as well as environmental significance and are valued as relaxation and refuge spaces within the city. However, large parks have the sustainability disadvantage of breaking connectivity between different urban functions and therefore increasing car usage. From an ecological perspective, parks are sometimes being criticized as being too artificial (and therefore less sustainable than a wildlife area) and disconnected from the natural environment. In addressing that issue, green corridors were introduced along railways and waterways to allow interconnection of natural spaces and wildlife migration. [2]
There are many benefits for vertical greenery right now in middle of polluted and crowded cities like Tehran. The main reasons for utilizing vertical greenery are:
1- Shortage of unoccupied lands for urban greening in most metropolitan areas.
2- High-rise construction and the growth rate of overall of grey surfaces where flat green spaces can't develop more. 
3- More benefits through utilizing vertical green skins rather than ordinary green spaces.
4- The possibility of making an integrated green space network by greening each building and attaching separated parks and green spaces to them.

3-2- Past experiments

From many years ago in Iran, the façade and walls of traditional and semi modern buildings were covered by climbing plants like Ivy (Hedera Helix) and Grape ivy (Ampelopsis). It seems that using these plants refers to an ornamental view to vegetation and never been heard people say “Green wall” to them or use for ecological benefits as a consciously selection.
After the arrival of a new wave of global awareness about environmental problems and climate change to Iran, many environmental activists and elites are beginning to be aware about this environmental crisis and its impact on urban areas. Recently, the research of vertical greenery has escalated in universities, environmental NGOs and architectural magazines. Still in some schools of architecture, there is a decorative viewpoint to vertical greenery by professors and tutors! But encouraging change is beginning.  

 

Figure 3: An extensive green roof, Tehran. greenroof.ir

 

 3-3- Green roofs

Green roofs are simply vegetated roof covers constructed atop and across a roof deck. They sometimes are called ecoroofs, sky gardens, even skyrise gardens. As living roofs, they contrast starkly with the average inert, hot, barren roof. The greatest potential of green roofs lies in their capacity to cover impervious roof surfaces with living, breathing, permeable plant material. Green roofs are healthy, sustainable, and regenerative roof landscapes that can help protect our environment by diminishing developmental impacts on our communities. They are one sustainable design element in the palette of today’s ecological designer. [7]

Figure 4: Green façade; the center for humanities and cultural studies, Tehran. 

 

Although green roofs have been part of the vernacular architecture for centuries, the contemporary green roof with the required technology to match modern city buildings was developed and gained social and political support in Europe, mainly by the German speaking countries in the last 40 years. [8]

They can:
1-reduce ambient air temperature, energy use, and utility costs;
2-help cleanse the air and water;
3-utilize local and recycled materials;
4-extend the life of the roof;
5-improve aesthetics; and
6-create green space for humans and wildlife while providing a psychological
7- and physical respite from urban surroundings. [7]

Figure 5: Ivy wall, the simplest way for creating a living wall.

 

3-4- Living walls and facade greening

The term “vertical garden” is used to define the growing of plants on, up, or against the façade of a building. Strategies for vertical garden development include: planting in the ground at grade; planting in planter boxes (at grade, attached to walls, on window ledges, balcony rails and as part of horizontal and vertical sun screens over windows, doors and glazed areas); and planting in a vertical hydroponic system. Suitable plants include a wide variety of perennial and annual vines as well as espaliered trees.

Fig. 6 Qeytarieh residential complex, Tehran. http://archnet.org

 

A vertical garden is essentially a living cladding system with many of the benefits of a green roof, and often without the added weight or cost implications. Vertical greening has more potential to impact the area per building, with greening of a building’s façade encompassing four times the area of the roof. For a high rise building, this can increase to twenty times the area of the roof. In fact, vines can be trained to cover a low roof as well as the walls of a building. [9]

1-3-4- Green facades

Green facades are a type of green wall system in which climbing plants or cascading groundcovers are trained to cover specially designed supporting structures. Rooted at the base of these structures, in the ground, in intermediate planters or even on rooftops, the plants typically take 3-5 years before achieving full coverage. Green facades can be anchored to existing walls or built as freestanding structures, such as fences or columns. Self-clinging plants such as English Ivy have commonly been used to create green walls. Their sucker root structure enables them to attach directly to a wall, covering entire surfaces. These aggressive plants can damage unsuitable walls and/ or pose difficulties when the time comes for building maintenance and plant removal.
Technological innovations in Europe and North America have resulted in the development of new trellises, rigid panels and cable systems to support vines, while keeping them away from walls and other building surfaces. Two green facade systems that are frequently used are Modular Trellis Panel and Cable and Wire-Rope Net systems. 

2-3-4- Living Walls

Living wall systems are composed of prevegetated panels, vertical modules or planted blankets that are fixed vertically to a structural wall or frame. These panels can be made of plastic, expanded polystyrene, synthetic fabric, clay, metal, and concrete, and support a great diversity and density of plant species (e.g. a lush mixture of groundcovers, ferns, low shrubs, perennial flowers and edible plants). Due to the diversity and density of plant life, living walls typically require more intensive maintenance (e.g. a supply of nutrients to fertilize the plants) than green facades. There are various forms of living walls, with the main differences occurring between interior and exterior designs. [10]

4- Programs and Barriers

Recently, rules about green roofing in large cities have been approved; they include incentive programs, i.e. the ability to increase building density on top of public and governmental buildings if a green roof or roof garden is installed.  Also the Headquarter of Vertical Green Space Development”, a governmental organization, began its work in the “Tehran organization of green spaces and parks”. Some municipal branches and “Park and green space organization” headquarters have a green roof now, or their facades became green during last years; although the quality is questionable!

Additionally in the past few years, at plants and flowers fairs in Tehran, a handful of companies presented their new products and catalogues. These public fairs are very important public relations for the green industry today. The presence of foreign companies’ participation would improve the quality and diversity of methods and technologies with the possibility of making more connections. 

The main barriers to future development are created by the lack of understanding of the role of green skins among people and environment-construction managers. Knowledge through education and exposure to existing technologies is critical. Other barriers to developing green systems are economic, lack of access to technology, and the deficit of research for professionals.

Figure 7: Living wall, Tehran plants and flower fair, 2011.

 

5- Existing exemplars

Generally facade greening and living wall projects have greater limitations for implementation in Iran except for those traditional examples of green walls made of self growing or climbing plants requiring minimal technology, watering and maintenance. Contemporary examples are very restricted and new. 

Figure 8: ‘District 10’ of Tehran Municipality. parks.tehran.ir
 

In addition, vertical vegetation systems are typically very expensive (e.g. living wall panel systems) or very slow to mature (e.g. climbing vines on trellises) or both. Therefore, when vertical vegetation projects are considered, it is beneficial to be able to make informative design decisions at an early stage. [11]
In recent years, few professional Iranian companies have been established to work under other foreign licenses with imported products and technology from companies in Germany and France. The office of Zinco Company (Zinco-Iran) opened recently but there is no specified information about their implemented works until recently.
The acceptable exemplars with minimum of standards are limited. A semi arid region is not a heaven for green roofers but choosing plants intelligently, using suitable layering systems and an irrigation system are the mysterious components of successful green roof that normally are not specified in most of these exemplars! Certainly ecological and environmental benefits of a green skin are the last or forgotten part of it here!
In facade greening on "District 10 of Tehran Municipality", the plants only cover a small surface on the bottom part of northern facade while other facades (even the western facade!) have been left grey! This half done greenery probably comes from emphasizing the eye level views of a high rise building. Furthermore, this green facade has been installed in order to comply with regulations of the municipality’s greening codes without attention to other functions of a green facade like energy efficiency. (Figure 8) 

 

The Ekbatan green roof project located in midst of a concrete and glass blend; an early example of modern urbanization. Using a green wall and a green roof both on rooftop creates an interesting and making balance between hard and soft landscape. That's one of the acceptable examples right now. (Figure 9, 10)

Figure 9: Ekbatan green roof project, Tehran. greenroof.ir

Figure 10: Ekbatan green roof project, Tehran.

 

 

 

 

 

 

 

 

6- Critical assessment: Necessity of changing minds!

The worst thing underway in vertical greenery in Iran is an ornamental view to it, an orchard on rooftop! From this standpoint, decorative beauty and large space are more important than other benefits. In many of green roof designs in Iran there are no significant differences between landscaping on land and on rooftop!
The broad usage of lawn which is common in contemporary landscaping in Iran has continued on green roofs. (Figure 11) The necessity of shifting opinions comes from this misplaced ornamental view of ground level greenery on green roofs. The plant selection and style of landscape designs are the strongest reasons for this claim. Heavy elements like large trees, heavy stones, and dominance of hard landscape against soft are also other problems that made by inexperienced green roofers and designers. (Figure 12). 

 

 

Figure11: The excessive usage of lawn needs high amount of watering in a dry place!

 

Unused spaces in some green roofs or only making margins around (Figure13); ornamental flowers and decorative pruned trees are other reasons too. Sometimes seems that views from bottom of building for people are more important than of a perfect space for landlords!
We require educational and learning programs. The change must be happen in two main portions:
1- Shifting traditional view points about vertical greenery.
2- Adapting laws, codes, regulations and incentives in works and designs of law makers, designers and contractors.

Figure12: Is it landscaping on a rooftop or on the ground?!

 

 

 

 

 

 

7- Conclusion

 

Totally, we are on the beginning of a long way in Iran. There are a few programs which are partially working and some architects and environmental designers are trying to develop and use green skins. However, we need the experiments and knowledge of pioneers, particularly from similar climates.  Many years ago European and North American countries established associations, institutes and communities for educational and networking purposes while hand in hand influencing or assisting governments to implement incentive and strategic programs. We can see the results of them in successful cities like Toronto, Chicago, and Stuttgart.
At least educators must start to introducing vertical greenery in university classes and all architecture, landscape architecture and environmental design students must take courses in this field. Definitely the future of architecture and construction will be ecologically; that’s not a selection or prediction!

Figure13: The minimum usage of roof capacity filled by ornamental and seasonal flowers and plants!

 

 

Acknowledgment: Special thanks to Karla Dakin, American landscape architect and green roofer, for her great help.

References:
[1] Behbahani Irani, H; Khosravi, F; “Iranian Garden: A Place of Coexistence: City-Nature-Landscape, Case Study: Tehran Gardens in 19th century”, Environmental Sciences, No. 13, pp. 79-87, 2004.
[2] Loh, Susan; Stav, Yael, “Green a city grow a wall” In: Proceedings of the Subtropical Cities 2008 Conference: From Fault-lines to Sight-lines: Subtropical Urbanism in 20-20, 3-6 September 2008, State Library of Queensland, Brisbane, Queensland.
[3] Hooshangi, Farideh “Isfahan, City of Paradise A study of Safavid urban pattern and a symbolic interpretation of The Chahar-Bagh gardens”, Master of Architecture Thesis, Carleton University, School of Architecture, Canada, 2000: http://www.collectionscanada.gc.ca/obj/s4/f2/dsk1/tape2/PQDD_0026/MQ5237...
[4] Moghtader ,M. R. and  Khansari, Mehdi , “The Persian Garden: Echoes of Paradise”; Mage Publishers, First edition, 1998.
[5] Bahrami, B; Salehi, E; Jafari, H; Irani Behbahani, H; “Urban Ecological Landscape Planning and Design From the Garden City toward Modern City- A Case Study: Tehran City in Iran”; International Journal on“Technical and Physical Problems of Engineering”, Issue 11 Volume 4 Number 2 Pages 128-134, 2012.
[6] Skinner, J.; “Urban Density, Meteorology and Rooftops”, Urban Policy and Research, 24:3, 355 – 367, 2006.
[7] Velazquez, Linda S.; “Organic Greenroof Architecture: Sustainable Design for the New Millennium, Making the most of your building's "fifth façade"”, © Wiley Periodicals, Inc. Environmental Quality Management, Summer 2005.
[8] Dunnett, N. & Kingsbury, N., Planting green roofs and living walls, Timber Press: Portland, Or. and Cambridge, U.K., pp. 254, 2004.
[9] Steven W. Peck, Chris Callaghan, Monica E. Kuhn, and Brad Bass; “GREENBACKS FROM GREEN ROOFS: FORGING A NEW INDUSTRY IN CANADA”; Prepared for Canada Mortgage and Housing Corporation, March 1999.
[10] GRHC; “Introduction to Green Walls Technology, Benefits & Design”, 2008
http://www.greenscreen.com/Resources/download_it/IntroductionGreenWalls.pdf
[11] Stav, Yael & Lawson, Gill M. (2012) Vertical vegetation design decisions and their impact on energy consumption in subtropical cities. In Pacetti, M., Passerini, G., Brebbia, C.A., & Latini, G. (Eds.) The Sustainable City VII: Urban Regeneration and Sustainability, WIT Press, Ancona, Italy, pp. 489-500.