ctbuh.org/papers

Title: A “Flight Manual” for Air Plants

Authors: Stuart Jones, Technical Director, Hyder Consulting Grant Harris, Principal, Ironbark Environmental Arboriculture

Subject: Sustainability/Green/Energy

Keywords: Green Roofs Green Walls

Publication Date: 2015

Original Publication: CTBUH Journal, 2015 Issue III

Paper Type: 1. Book chapter/Part chapter 2. Journal paper 3. Conference proceeding 4. Unpublished conference paper 5. Magazine article 6. Unpublished

© Council on Tall Buildings and Urban Habitat / Lloyd Godman; Stuart Jones; Grant Harris Sustainability/Green/Energy A “Flight Manual” for Air Plants The green fabric that clothes the earth is fraying. Sadly, through overuse, the garment we depend upon is wearing out. The construction of buildings and urban infrastructure like roads and car parks become “dead pixels” in the living image of the planet. Repairing the old garment by stitching plants into the structures of our cities is a vital option. Incorporating plants into tall building design is an important aspect of this restoration project. This paper describes Lloyd Godman Stuart Jones the successful installation of plants on the exterior of Melbourne’s iconic Eureka Tower (see Figure 1) and provides an example of a selective vertical gardening system with a high Environmentally Sustainable Development (ESD) factor, which eliminates the requirement for plant growth substrate.

The Importance of Vertical Gardens years. The urbane tall buildings we now see may quickly become historic symbols of a past From simple organisms, evolving through age, when architecture was less connected to Grant Harris millions of years to complex biological systems, nature. vegetation has obeyed its innate compulsion Authors to cover the planet with a living green Lloyd Godman, Ecological Artist membrane that supports all other life. Plants Vertical Garden Systems 90 Shaftesbury Ave., St. Andrews VIC 3761, Australia have waxed and waned in their fight to cover t: +61 44818 8899 geological surface since the Ordovician period Utilizing living plants as an effective façade e: [email protected] www.lloydgodman.net (495 million years ago), and as we progress poses many problems. Unlike metals, glass and through our current era, the Anthropocene, it is concrete, which are inert, plants require Stuart Jones, Technical Director Hyder Consulting evident that human actions are the primary nurturing. Concerns over increased Level 16, 31 Queen St., Melbourne determinant for the survival or extinction of maintenance costs (Zhang et al. 2012), damage VIC 3000, Australia t: +61 3 8623 4000 species. The exponential rate at which our cities to façades, and increased loading on structural e: [email protected] have expanded demands that we now plan systems (Wood et al. 2014) are barriers to the www.hyderconsulting.com and act to integrate our urban centers into the implementation of green roofs and walls. Grant Harris, Principal biosphere of the planet. The combined surface Zhang et al. provide a succinct definition of Ironbark Environmental Arboriculture 3/11 Coate Avenue, Alphington of high-rise buildings and other urban “intensive” and “extensive” green roof systems. VIC 3078, Australia infrastructure can provide significant areas to t: + 61 41560 7375 e: [email protected] support plants, and weave back the threads of Intensive green roof systems are characterized green fabric. by deep (greater than 15 centimeters) growing Lloyd Godman is an ecological artist and has an media, opportunities for a diverse plant palate MFA from RMIT University, Melbourne. He has had more than 45 solo exhibitions and been included in Integrating plants into the built environment on the rooftop, and high maintenance more than 250 group exhibitions. His current work improves air quality, moderates temperatures requirements. In many cases, intensive green explores living plant works and “super-sustainable” art. In 2011, he began creating suspended rotating plant (Saadatian et al. 2013), improves human roofs are being replaced by extensive green sculptures and since then has worked with plants on well-being, lifts the spirit (Townsend & roofs, which have a much thinner, lighter media tall buildings, including Eureka Tower, Melbourne. Weerasuriya 2010), and can provide habitat for (thus fewer structural requirements), and offer Stuart Jones has recently been appointed Technical other species (Oberndorfer et al. 2007). In fewer, but potentially more practical plant Director for Hyder Consulting in Melbourne. Previous to this he was the Owner/Director of Point March 2015, it was promising to see a law choices. 5 Consulting in Melbourne for 14 years. Stuart has passed in France, which mandates that over 25 years’ professional experience in all phases of project delivery and specializes in creative structural rooftops on new buildings built in commercial Building on Zhang’s categorization of green design, with extensive experience in Australia and zones must either be partially covered in plants roofs, the authors propose that incorporating throughout Asia. or solar panels. This mandate draws a line, vertical gardens into a building’s design can Grant Harris is the principal of Ironbark Environmental whereby inspiring contemporary architecture employ two systems, which are adaptive or Arboriculture, with more than 12 years’ experience in the arboricultural sector. He also holds a degree will be measured by the successful integration selective. in Environmental Science (Wildlife and Conservation of living green texture into the fabric and form Biology). His particular areas of interest are the use of green infrastructure to mitigate urban heat island of the structure. Imagination and Adaptive systems effects and urban ecology. experimentation have driven a welcome Analogous to intensive green roofs, adaptive expansion of roof and vertical gardens in recent vertical gardens require the environment to be

38 | Sustainability/Green/Energy CTBUH Journal | 2015 Issue III adapted to support the plants’ biological have no requirement for soil and tolerance of demands, which will vary depending on the extremes in moisture availability. Both of these ecophysiological characteristics of the selected are attractive characteristics when choosing species. This condition is met by mesh- plants for utilization in a selective vertical mounted plant growth substrate, irrigation and garden system. fertilization. The benefit of adaptive systems is that they allow a greater selection of species; Tall buildings present an extremely however, they have limitations, including the challenging environment for plant growth, cost of installing and maintaining structures to where consistently high wind speeds increase support plant growth substrates (Pérez et al. transpirational losses and thereby increase

2011). water stress on plants growing in these Figure 1. Eureka Tower, Melbourne. © John Gollings environments. Tillandsia bereri and a hybrid, Selective systems Houston, were selected to test the concept of leading to the colloquial name of “air plant.” Akin to extensive green roofs, selective systems a selective vertical garden system because This adaptation removes the requirement for use critical species selection to identify plants they have the following characteristics: a plant growth substrate to be installed on the that naturally grow in environments similar to building façade. The lack of water-seeking those encompassing an existing building’s Drought tolerance roots also negates building managers’ façade. They have the advantage of reducing or Bromeliads minimize transpirational water concerns about potential damage and eliminating the requirement for plant growth losses by utilizing the crassulucean acid maintenance costs. substrate and associated installation and metabolism (CAM) cycle, in which the maintenance costs. The limitation of selective stomata are closed in the heat of the day and Absorption of airborne pollutants systems is a reduced plant palette. open to uptake CO2 at night, releasing oxygen The trichomes of Tillandsia have a high during darkness (Benzing 1990). Moisture and absorptive capacity, which allows them to nutrient uptake occur through specialized absorb air pollutants rapidly (Li et al. 2015). Plant Selection trichome cells, further reducing transpirational The installation of large Tillandsia screens on water losses; these adaptations make tall buildings has the potential to act as an air Epiphytic plants are those that use other plants Tillandsia very drought-tolerant. filter for the building and surroundings. for mechanical support; a diversity of plant groups has evolved to fill this environmental No requirement for soil Minimal weight niche. Life as an epiphyte, high in the forest One adaptation of Tillandsias to the epiphytic Based on previous installations, the weight of canopy, exposes the plant to greater life-mode is the modification of the role of the a Tillandsia screen is estimated to be 3 kg/m2, fluctuations in moisture availability in roots from that of moisture and nutrient which is minimal in comparison to adaptive comparison to their terrestrial cousins, nestled absorption to that of “hold-fasts” that function systems that require plant growth substrates comfortably in the soil below. Tillandsia (see only to attach the plant to the substrate and supporting structures. The light weight of Figure 2), which is a genus of the Bromeliad (Benzing 1990). The leaves of the plant replace Tillandsia means they are perfectly suited for family, includes more than 1,000 epiphytic the role of the roots and sequester moisture use on screens (Pérez 2011) and can be species (Benzing 1990) that have evolved to and nutrients directly from the atmosphere, placed in arbitrary shapes on the building

The leaves of the Tillandsia sequester “moisture and nutrients directly from the atmosphere, removing the requirement for a plant growth substrate to be installed on the building façade. Figure 2. Tillandsias, the “air plants” chosen for the experiment. ” CTBUH Journal | 2015 Issue III Sustainability/Green/Energy | 39 Figure 3. Tillandsia plant cages installed at Eureka Tower.

exterior (Wang et al. 2011). Plant screens have ordinal health categories. These were dead farthest from the growing tip was observed. demonstrated effectiveness as passive (<10% live growth), very poor (<25% live This is attributed to the acclimatization of the energy-saving systems (Pérez 2011). growth), poor (<50% live growth), fair (>50% plants to the new environment. All of the live growth), good (>75% live growth), and plants maintained high levels of health, with excellent (>90% live growth). Plant health was the exception of one on Level 91. This plant Methods assessed by visual observation of each leaf of was located in the most sheltered position, an the subject plant. When an individual leaf was external stairway niche receiving the least rain The project team installed eight Tillandsia in a state of decline (>35% dead tissue) this and sunlight. plants in wire cages in groups of two, affixed to was categorized as dead. The relative secure points at four locations on the Eureka proportion of live and dead leaves was used During the February 25, 2015 inspection, this Tower. Plant cages were installed at Levels 56, to assign a health category to each plant. No plant was observed to be the only plant to 65, 91, and 92 (see Figure 3). The aspect of the supplementary irrigation or fertilization was have flowered during the experiment period building at which the plants were placed was provided to the plants during the installation and to have formed new “pups” (vegetatively determined by the location of available period. produced new plantlets). During the May 20, balconies and cage attachment points. Plants 2015 inspection, plants on Levels 56 and 65 were photographed and labeled prior to Weather records were obtained from the were also observed to be forming pups. placement in the cages. Eureka Tower meteorological station, and periods of low rainfall and high temperatures Plants were inspected four times in the period were identified during the survey period. Discussion between June 17, 2014 and May 20, 2015, and health categories were recorded for each The trial results indicate that Tillandsias are specimen (see Table 1 and Figure 4). The Results able to survive on the exteriors of tall proportion of living foliage was used to buildings without supplementary irrigation. evaluate plant health (Costello 2003) and During the October 16, 2014 inspection At approximately 300 meters above grade, the observations were assigned to one of six session, some leaf die-back at locations Level 92 installation is the world’s highest

Level Height Plant Date of visit (m) winter summer winter The trial results indicate that Tillandsias Jun 17, Oct 16, Feb 25, May 20, 2014 2014 2015 2015 “are able to survive on the exteriors of tall 56 179.5 B1   M M 56 179.5 H2   M M buildings without supplementary 65 208.5 B3   M M irrigation. At approximately 300 meters 65 208.5 H4   M M 91 292.3 B5   M M above grade, the Level 92 installation is 91 292.3 H6   M M the world’s highest plant installation on a 92 298.3 B7   M M 92 298.3 H8   M M building and a proof of concept for B Tillandsia bergeri H Tillandsia ‘Houston’ Flower MPups selective vertical garden systems. Plant state:  Excellent  Good  Fair  Poor  Dead ” Table 1. Tillandsias installation results over time. 40 | Sustainability/Green/Energy CTBUH Journal | 2015 Issue III plant installation on a building and a proof of or reticulated (pressurized) watering system, concept for selective vertical garden systems. whereas the climbing plants originally installed continued to struggle. By February Buildings within the urban environment are 2015, the climbing plants were still in place, essentially pieces of refined geology, so when but covered much less of the netting than in endeavouring to integrate plants into 2011, suggesting the effort to replant and high-rise buildings, one must first observe maintain them had exceeded the plants that inhabit similar hostile environmental reward. The simple experiment environments in nature. Basically, buildings offered a model for a larger project with City are high vertical cliffs of rock with no humus, of Melbourne – Airborne. Figure 4. The Tillandsias at Level 92 of Eureka Tower on often no water retention, and extreme May 20, 2015. Pups can be seen on the rightmost plant. temperature changes, which is the type of © Toby Reed The Airborne project environment to which some species of Supported through a City of Melbourne Arts Tillandsia have adapted and thrive in. Plants Tillandsia in Other Urban Greening Projects Grant in 2013, the Airborne project presented on tall buildings are subjected to high wind eight air plant sculptures, which were installed speeds and limited soil volumes, which places The CH2 building experiment for 13 months in central Melbourne with no great pressure on irrigation systems to provide In 2011, the opportunity arose to stage a soil or auxiliary watering system in a water to counteract transpirational losses. demonstration of the Tillandsia in a vertical demanding location: Les Erdi Plaza, Such demanding ecophysiological urban condition. Collaborating with Ralph Northbank, Melbourne, adjacent to a busy rail environments mean that, for some plant Webster, senior architect of the Melbourne corridor at Flinders Street Station. Despite species, no matter how much water is City Council, the opportunity came to prolonged periods of dryness, including provided to the root system, they are simply experiment with a few air plants in a record heat (with five consecutive days over not able to uptake water at the rate of demanding location on the new CH2 building 41°C), the plants grew and even flowered. transpiration. For adaptive systems the located at 240 Little Collins Street (see Figures functioning of the irrigation is critical, and 5, 6, and 7). Existing climbing plants had After 13 months, the growth habit of the there have been high-profile cases of green struggled to thrive along the north wall, plants had changed. They were more walls dramatically failing (Klettner 2009). The which is subject to very hot, dry winds, with compact in structure, with shorter, harder advantage of selective systems is that they are the wind tunnel effect of a narrow alley leaves, and more silver in color due to insulated from this threat. exacerbating the dehydration. After 18 increased levels of trichomes. However, pup months, the Tillandsias proved that, while they production was more prolific, with seven or grew slowly, they could thrive solely on their eight per plant, many more than in a less adaptive biological systems, requiring no soil stressful location, where pup production

Figure 5. CH2, Melbourne. © David Hannah Figure 6. CH2 north façade in 2011. The location of Figure 7. CH2 north façade in February 2015 shows the the Tillandsia is marked with the red circle. Note the climbers with less growth than in 2011. inconsistent growth of the climbing pants.

CTBUH Journal | 2015 Issue III Sustainability/Green/Energy | 41 Figure 8. The Airborne project, Melbourne. might normally be two or three. The authors supportive of the experiment, and there is The Future: A “Flight Manual” for Air Plants attribute the increased production to the potential for a larger project in the future. plants’ biological “insurance” – if one or more Buildings are statements; architects define pups die, then the plant has more reserve The authors continue to believe that “air plants” surfaces and geometries within the overall shoots from which to prosper. Also, a clump of provide a significant advantage over plants that structure through the use of metals, glass, plants creates greater shade, protecting other need to be supported by active watering and concrete, and synthetics. However, plants in the colony. Of several thousand fertilization systems, not least because of the responsible architecture in the 21st century individual Tillandsia used on the eight probability of “extreme events” that could rob not only considers the advantages of plants sculptures, only two plants died during the the plant of its water and/or nutrients. within the urban environment and simply 13-month installation. “tacks” a vertical garden onto a wall, but draws With a reticulated watering system, an extreme from the diverse array of possible living Rotating on swivels, the air plant sculptures event might be: textures of green, juxtaposing them against dissipated energy instead of becoming existing materials and textures, into the overall excited, as a fixed sail might. During this ƒƒ a pump failure, blocked pipe or drain visual design of the structure at the concept period, a storm with winds of up to 115 kph ƒƒ a weather event like wind, cold, heat, or stage. The addition of this new living material ripped a large sculpture from its mounts only drought offers an exciting potential for the future, a few hundred meters away, and tragically ƒƒ tracking, a condition where the liquid drips where imagination can soar to greater brought down a brick wall that killed three from the wall, down a leaf surface, and falls heights. people – but it had little effect on the living onto the ground below, which denies water sculptures. While vertical and rooftop gardens to the plants below this point Imagine tidal gardens with multiple screens occupy surfaces, the Airborne project proved that move independently at various rates up that air gardens can successfully step beyond Vertical and roof gardens most often fail and down a building’s façade. Imagine whole earthly confines to suspend between because these factors are not considered or façades of plants that shimmer on the wind structures in open space, providing living, maintained. Because Tillandsias have no need and move from aspect to aspect on a overhead screenings (see Figure 8). of soil medium or a reticulated watering building. Imagine a modular system, where system, the risk factors are reduced. Tillandsia are suspended across an open Importantly, there is also no risk of water public space like a plaza during summer, Biological Insurance ingress to an undesired aspect of a building, creating dappled shade, and then simply nor is there risk of roots penetrating and moved onto a building’s façade for the cooler The Eureka air plant experiment strongly damaging the façade or structure. winter months when the sun is welcome. suggests that Tillandsia plants can be grown Imagine roof gardens with suspended with no soil or auxiliary watering system on Therefore, even if such an experiment should Tillandsia screens designed to create the tallest of buildings in a city like Melbourne, prove a “failure” with widespread plant deaths, modulated shade patterns to complement and opens a portal for installing plants in a the lightweight characteristics of the Tillandsia other, less stress-tolerant plants that might creative but effective and environmentally would not pose the same kinds of issues as grow on the roof surface below. beneficial manner on high-rise buildings. The hard-tissue plants like vines, such as scarring on management of the Eureka Tower was very and penetrations in the façade, if at any time they were detached from the building.

42 | Sustainability/Green/Energy CTBUH Journal | 2015 Issue III Figure 9. Example of Tillandsia screen. Figure 10. View from inside of experimental movable living Tillandsia plant screens.

Tillandsia screens (see Figures 9 and 10) could The results of these experiments with Tillandsia PÉREZ, G.; RINCÓN, L.; VILA, A.; GONZÁLE, J. M. & CABEZA, be: over the past few years have shown that L. F. 2011. “Green Vertical Systems for Buildings as Passive Systems for Energy Savings.” Applied Energy. Vol. 88: designers can act with the knowledge and 4854–59. ƒƒ moved horizontally or vertically in parallel confidence that these systems work. Air from the building’s façade across a window gardens break new ground, offering fresh SAADATIAN, O.; SOPIAN, K.; SALLEH, E.; LIM, C. H.; RIFFAT, S.; SAADATIAN, E.; TOUDESHKI, A. & SULAIMAN, M. Y. 2013. “A ƒƒ rotated on a curved axis, so while they can dimensions by incorporating plants in our cities Review of Energy Aspects of Green Roofs.” Renewable and be set to block direct sunlight, they can also for high environmental benefit. They write a Sustainable Energy Reviews. Vol. 23: 155–168. allow a clear view out the window “flight manual” for plants to escape their earthly TOWNSEND, M. & WEERASURIYA, R. 2010. Beyond Blue to ƒƒ set on a swivel off the building and rotated confines in the urban habitat and occupy new Green. Melbourne: Beyond Blue Limited. ƒƒ positioned horizontally out from the and existing space within our cities.  building for shading, or hinged upward. WOOD, A.; BAHRAMI, P. & SAFARIK, D. 2014. Green Walls in High-Rise Buildings. Chicago: Council on Tall Buildings and Unless otherwise noted, all photography credits in Urban Habitat. this paper are to the authors. Because there is no need for reticulated liquid, ZHANG, X.; SHEN, L., TAM, V. W. Y. & LEE, W. W. Y. 2012. “Barriers to implement Extensive Green Roof Systems: A screens of Tillandsia can defy gravity in ways Hong Kong Study.” Renewable and Sustainable Energy that are restrictive for other vertical garden References Reviews. Vol. 16: 314–19. systems. They can be mounted on façades BENZING, D. H. 1990. Vascular Epiphytes. Cambridge: that overhang or have complex, intricate Cambridge University Press. geometric or organically curved surfaces. For COSTELLO, L. R.; PERRY, E. J.; MATHENY, N. P.; HENRY, M. J. & future green architecture, they offer a flexible GEISEL, P. M. 2003. Abiotic Disorders of Landscape Plants: A living texture which, with little maintenance, Diagnostic Guide. Richmond: University of California Agriculture & Natural Resources Publications. can be juxtaposed against glass, steel, or concrete. In fact it is possible to create living WANG, F.; ZHANG, X.; TAN, J. & LI, X. 2011. “The Thermal façades that alter their shape and form during Performance of Double Skin Façade with Tillandsia Usneoides Plant Curtain.” Energy and Buildings. Vol. 43: the day. 2127–33.

As bromeliads grow asexually, over time they KLETTNER, A. 2009. “Amazing Pictures: London’s First Living Wall Dies.” Architect Journal. http://www.architectsjournal.co. can be harvested to provide a bioresource to uk/news/daily-news/amazing-pictures-londons-first-living- create new material. A significant advantage wall-dies/5207086.article. of integrating Tillandsias into a green building LI, P.; PEMBERTON, R. & ZHENG, G. 2015. “Foliar Trichome- design is that a “living wall” can be completed aided Formaldehyde Uptake in the Epiphytic Tillandsia in sections, along which, over time, the plants Velutina and Its Response to Formaldehyde Pollution.” are harvested and assigned to the next Chemosphere. Vol. 119: 662–67. section of a wall. A high-rise façade might be OBERNDORFER, E.; LUNDHOLM, J.; BASS, B.; COFFMAN, R. R.; completed several levels at a time. Unlike DOSHI, H.; DUNNETT, N.; GAFFIN, S.; KÖHLER, M.; LIU, K. K. Y. current vertical gardens, there is no operating & ROWE, B. 2007. “Green Roofs as Urban Ecosystems: Ecological Structures, Functions, and Services.” BioScience. Vol. cost of water, pumps, and no need for 57: 823–33. replacement plants.

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