6.3.6 Pot Plants on Plinths and Other Acts of Ecological Reductionism

“Our reasons for valuing nature in cities needs to move beyond the “selfie” view that puts a bit of greenery in the frame of urban portraiture.” Downton, 2018.

No matter the quantity thereof, ecologically, plants that reside in pots atop balconies on the exterior of glass, steel, and/or concrete tower blocks amount not to ‘forests’, ‘urban’ or otherwise, for forests constitute not mere collections of individual plant specimens, but highly connected networks of specimen populations. Nonetheless, glorified pot plant assemblages, as exemplified by Boeri Studio’s Bosco Verticale [Fig. 69] (Stefano Boeri Achitetti, 2018a) are awash in the industry press and media.

Acts of “overly simplistic” ecological reductionism (Davies and Doick, 2017), though promoted as “biological” habitats (Frearson, 2014), in not one, but several ways, the ilk of Bosco Verticale reduce biota to baubles. Within forests of all variants, different ecological functions typically operate at different strata [ground, surface, or canopy], wherein, species are both physiologically and behaviourally adapted to particular spatial relations both between their populous, and other variables, both biotic and abiotic. Shift a specimen’s relation to those variables and its capacity to maintain processes such as reproduction, dispersal, and symbiosis, will likewise shift. As relates to natural hazards, such as drought, heatwaves, disease, and storms, the exchange of information and nutrients across root and mycorrhizal networks that extend across the forest floor is fundamental to resilience, therein in removing species from the horizontal to the vertical plane one increases their exposure to these, and other environmental hazards. However, absence of ecological integrity is, arguably, the lesser of the failings inherent in proposals which, like Bosco Verticale, suggest not notion that, carbon-based, in and of the right conditions [i.e. a dry storm] their baubles are both conductive and flammable.

What evidence is there to suggest that Bosco Verticale and its vertical forest-kind may present a fire risk? In 2017 a casually discarded cigarette ignited a potted plant, which then ignited the balcony where it was placed, from which fire spread inwards and upwards, incinerating three floors, and the apartments therein in the process (Giordano, 2017). As evident from earlier chapters, that carbon-based materials are combustible is indisputable. Likewise, that ignition sources come in many and varied sources is not a matter of dispute, but of fact. Consequently, whereupon flora is being placed in abundance on building exteriors, reasonable is the speculation that, somewhere, sometime, be the ignition source an act of arson, accidental, an electrical discharge that heats the atmosphere to c. 20,000°C [lightning], or other, that fire will be no stranger to vertical forests is not so much a matter of speculation as probability.

Of course, fire is by no means the only threat posed by vertical urban forests. Indeed, some risks, such as that of a tree, or number thereof, toppling during a storm is yet more accentuated whereupon those trees are upon tower blocks than within forests of the none-anthropogenic variant. But, in the former instance [i.e. a tree falling from several floors high] the risk of injury to both people and property is many times greater than the latter, the extent thereof calculable using Newton’s Second and Third Laws. Yet, as architecture critic Mark Minkjan has pointed out, even the ilk of MVRDV have produced vertical forest proposals as are so absent of attention to the very particular risks posed thereby as to be devoid of balustrades upon balconies containing trees, shrubs, and assorted other foliage (Minkjan, 2016). “Is architecture today anything more than make-up for real estate projects” Minkjan asked, adding, “Renderings hide the ugly sides of architecture and urban development, and the media buy it”. However, the media aren’t alone.

Awards to so-called ‘urban forests’ proliferate (Stathaki, 2017). Indeed, Bosco Verticale was celebrated by the RIBA no less. Beyond the architectural and into the wider built environment realm, oblivion to the fact that, as dendrologists from Evelyn onwards (1659) have recognised (Berg, 2016; Pyne, 2012), whether live or dead, in forests wild or cultivated, wood is flammable, is, again, rife. So wide-spread is use of imagery of vertical forests in social and other media as suggests some think them the poster-child of urban sustainability. Some claims go yet further still. Umpteen are they that be it in the print or pixels are hailing the scaling of Boeri’s tree-clad balconies from tower block to city as a means of mitigating climate change. According to the studio, whereupon their proposal for “the first Chinese Forest City” becomes a reality, some “10,000 tons of CO2” will be “absorbed” (Stefano Boeri Achitetti, 2018b). As discussed earlier, until the migration to mineral-based building fabrication, from the cities of the Zhou dynasty to the “Flowers [fires] of Edo” [Tokyo] and beyond, fires were as, if not more frequent in the cities of the East as West. Thus, in conjunction with climatological and hydrological trajectories [i.e. longer fire-seasons, less water availability], history suggests that if Boeri and his treescaper-hugging peers have their professional way, fires of the scale of they of Stuart London will ensue.

However, not merely are practitioners of architecture and the built environment proliferating concepts that evidence scant understanding of fire and its dangers. For example, whereupon a student project proposed to turn the “world’s largest trees” [they being fire-adapted sequoias] into “skyscrapers”, their aim to facilitate humanity’s “coexistence” with “nature” by ‘enabling’ said flora to “continue standing” [i.e. attempt to inflict permanency on a species of which the survival is dependent on temporality] (McKnight, 2017), it occurred not to the student, let alone the editorial team of Dezeen that the project, which was suggested for a Sierra Nevadan site, might pose a fire risk, let alone there need to address that risk within the proposal. Where some see ‘biomorphism’ another sees ‘bio-illiteracy’. Or, as Minkjan suggested, “green-wash” (2016). Arguably, architects, planners, and policymakers need recognise the fire risk inherent in vertical forests, and do so before, not after the advent of a case study, and having done so, reconsider the risks and opportunities of urban forests on the horizontal plane, like that depicted by Michael Sorkin [Fig. 70].

>Continue to Chapter 6.3.7 here.

The thesis is also available in PDF format, downloadable in several parts on Academia and Researchgate.

Note that figures have been removed from the digital version hosted on this site, but are included in the PDFs available at the links above.

Citation: Sterry, M. L., (2018) Panarchistic Architecture: Building Wildland-Urban Interface Resilience to Wildfire through Design Thinking, Practice and Building Codes Modelled on Ecological Systems Theory. PhD Thesis, Advanced Virtual and Technological Architecture Research [AVATAR] group, University of Greenwich, London.