Panarchistic Architecture :: Chapter #4 [4.5]

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.

PyroFutures: Wildland Fire Trajectories

“As to the precise form this future will take, even with the best will in the world modelling something as complex and interactive as the Earth’s climate may simply never be able to provide us with an accurate picture of what our planet will look like 50 or 100 years from now... Maybe then, the best way to gauge the nature of the world to come is to look back rather than project forward”. McGuire, 2013.

4.5.1 Overview

The parameters of Earth Systems ever shifting, having discussed the emergence of fire regimes at the local, regional, and global scale, and examples of floral and faunal evolutionary events that were catalysed thereby, the foci now shifts, sensu amplo Stuart Kauffman, to the adjacent possible, and to deciphering near-future planetary potentialities through the events of the past and present. Put succinctly, what are the wildfire and wider environmental scenarios a new WUI paradigm needs accommodate for?

4.5.2 Passing between two fires: From Fossilised to Future Fire Forecasts

Uncertain though Earth’s climatological future may be (Stern, 2006), humanity nonetheless has the capacity to anticipate how and why shifts in land, sea, and air temperatures may impact upon planetary systems. As discussed earlier, the palaeological record illuminates how “biogeochemical cycles” (Schneider, 1997), and the abiotic and biotic components thereof, have historically responded to climatic shifts. Contrary to the views of some conservationists, whereupon species were to remain in states of dispersal and population stasis [i.e. within set geographical ranges] their extinction would be not prevented, but accelerated. Several dozen paleobiological studies have made evident that at the scales of temperature change as both theoretical and computer modelling assert may occur in the near-term future, though, as Darwin anticipated (2008), floral and faunal species will shift their geographical ranges, they will do so not uniformly (Levin, 1999; Schneider, 1997; Botkin 1992, 2012): a species need not be on an anthropogenically defined ‘guest list’ to ‘get in’ to an ecosystem. Instead, ecological communities, which are “loosely defined assemblages of role players”, which within fire regimes include evaders, resistors, and endurers, will reconfigure in space and time not as superorganisms “with a common purpose and destiny” (Levin, 1999, p.33), but as individual species of which the physiological and behavioural capacity, symbiotic and otherwise, for climatic and wider environmental adaption varies from one unto another. Therein lies a truth in Gaia Theory [as distinct from the earlier Gaia hypothesis] in that, in the generic sense of the term, “life” is “tightly coupled with the air, the oceans, and the surface rocks” (Lovelock, 2016, p.xviii): life is beholden unto the biochemical constraints with which it coevolves (Ward, 2009).

From one geological epoch to another, trees have “moved, but old forests disappeared” (Schneider, 1997, p.94). Given the now innumerable ways in which humanity obstructs floral and faunal movements, be it building border walls, monocultures, shipping lanes, railways, flight paths, or levels of noise and/or light pollution so great as to undermine animal navigation sensory capacities, none are they as can accurately predict the extent to which non-human life will endure any such environmental changes as lay ahead. But, that several of the plant genera that have been discussed in this thesis, such as the conifer and the oak, have not merely survived, but thrived throughout climatic conditions both within and beyond the range as may manifest in the years, decades, and centuries, ahead, is without question. The matter thereof is both supported by the findings as have already been discussed [i.e. climatological, geological, and dendrological records], and by the physiologies of the flora, or more specifically their leaves, which preserved as fossils reveal the atmospheric carbon dioxide level to which they were adapted through “the number of microscopic pores” on their surface (Beerling, 2017, p.29).

In 2006, the Stern Review concluded that earlier speculations of future climate “were too optimistic”, stating “more recent evidence indicates that temperature changes resulting from BAU [business as usual] trends in emissions may exceed [a global mean surface temperature of] 2-3°C by the end of this century”, but that 5-6°C warming “is a real possibility” (Stern, p.ix). The IPCC’s 2013 assessment report predicted a marginally more conservative range of 1-3.7°C by the latter two decades of the century (Stocker et al, 2013). Should the lower of Stern’s estimates come to pass, mean surface temperatures would mirror those of the Mid-Pliocene Warm Period (McGuire, 2013), when Tundra and Taiga forests populated polar regions that are presently snow-capped, mid-high latitudes were 10-20°C warmer than today, of which the overall conclusion from “all model simulations” is that of “a generally warmer and wetter climate” (Salzmann et al, 2009, online). Given, “vegetation has greened across a third of the Arctic from 1982-2012” (Liberto, 2017, online); boreal forest wildfires in some regions now exceed the “fire regime limits of the past 10,000 years” (Kelly et al, 2013); and now numerous, microbes, mammals, and more faunal and floral species are re-populating polar regions and/or becoming more regionally productive, as each modifies the fast-changing territory as best befits their needs (Fountain, 2017; Dengler, R, 2017), we need no longer look merely to computer and theoretical models [Fig. 41], and the palaeological record to anticipate the near- medium term climate future.

4.5.3 Pandora’s Earth Systems Pyxis

“Contrary to popular belief, but confirmed by repeated natural disasters that have taught us otherwise, humans have amazingly little control over Mother Nature”. Kieffer, 2013.

Fire regimes are cyclical systems within systems, of which the configuration shifts in response to environmental change at broad local and global, seasonal and epochal scales. Studies of both paleo and present-day fire regimes have revealed a ‘Butterfly Effect’ [108] like chain of influence that extends from flora to climate. For example, fire- adapted species influence fire behaviour; fire behaviour influences cloud formation; cloud formation influences climate (Liu, 2005: NASA, 2017), which in turn, influences wildfires. The phenomenon has been observed in studies of the impact of wildfires on rain-cloud formation in wide-ranging regions, including Yellowstone National Park (Ibid), and Amazonia (Bevan et al, 2009). Findings from the former study linked the 1988 wildfires to a period of extended drought thereafter. Whereas, findings from the latter found rain-cloud formation had been delayed by a period of 15-30 days, thus extended the fire season. However, a further study established that not merely does wildfire smoke have capacity to extend the fire season, but to increase the formation of “positive cloud-to-ground lightning strikes” across distances of 2000>m (Bowman et al, 2011 citing Lyons et al, 1998), thus spark its own ignition. Therein lies another feedback chain: wildfires create smoke; smoke aerosols create cloud-to-ground lightning strikes; lightning strikes create wildfires; wildfires reduce rain-cloud formation, which in turn creates drought, which contributes to climate change, which Romps et al suggest (2014) creates more lightning strikes at a rate of 12±5% per/°C warming. The inter-relation of fire and drought is, likewise, evidenced in “many fire episodes” in the charcoal record (Odion et al, 2014), which also reveal rapid transition within fire regimes during periods of abrupt climatic change. Hence, while qualitatively distinct, the various fire regimes are not mutually exclusive entities, instead assemblages of species that reconfigure their distributions, populations, and inter-species dependencies in space and time. But, these are but a few of the items as are emerging from ‘Pandora’s Earth Systems pyxis’.

As wildfires have capacity to worsen drought, vice versa. Drought both increases tree mortality, therein tinder-ready fuel (Abatzoglou and Williams, 2016), while exerting physiological stresses that have been found to reduce fire-resilience in several conifer and fir species (Young and Sullivan, 2013). However, drought not merely reduces flora’s resilience to fire, but to pests and pathogens, such as woodboring beetles, while increasing the probability of outbreaks thereof (Anderegg et al. (2015; Thorne et al, 2017). In turn, pests and pathogens cause yet further physiological stress to trees, therein increase their probability of mortality, thus becoming tinder-ready fuel. Where some see a vicious circle, others see a virtuous one. But, whether one ascribes to the philosophical concept of creative destruction, or otherwise, that such is the complexity of the systems of atmospheric and ecological systems as are to hand as to limit humanity’s capacity to exert control thereover.

Evidence of the interplay between drought and wildfire can be found in publications and the landscape alike, and no less so than in California. Perusing articles archived from the summer of 2016, one finds the writing that 2017 would become one of the most notable wildfire seasons on record was on the digital wall:

“Choked with the detritus of at least 70 million dead trees, vast tracts of the landscape have become a botanical emergency room, parched by drought, invaded by damaging insects and infected with a deadly organism” Cart, 2016, online.

“Tree die-offs of this magnitude are unprecedented and increase the risk of catastrophic wildfires” Assoc. Press, 2016, online.

“Like tens of millions of matchsticks, California’s dead trees are ready to burn” Craft, 2016, online.

Adding to this anthropogenically ignited, but increasingly feedback-fuelled fire, smoke aerosols and climate change aren’t the only factors extending the duration of the fire season. As discussed earlier, human activity is likewise.

The relationship between wildfires and climate change expresses yet another Pandorian loop: within fire-prone regions, increases to mean surface temperatures in turn increase the probability of wildfire; wildfires emit carbonaceous aerosol and black carbon [the most potent of the greenhouse gases]; increases in greenhouse gases increase climate change, and so the cycle continues. Hence, a paradox, for though many assume that forests constitute carbon sinks, they can, within fire-prone regions, “turn to sources” (McGuire, 2013), as has already occurred in several regions (Gramling, 2017). Bringing perspective to the order of magnitude of emissions as may result from wildfire activity in the years ahead, U.S. wildfires are estimated to emit 290 million metric tons of carbon dioxide p/y, the sum thereof approx. 4-6% of its total annual emissions (National Science Foundation, 2007). However, wildfires are but one of several sources of greenhouse gas emissions over which humans have not control, including methane emissions from microbial activity in warming soils (Melillo et al, 2017), and from gaseous emissions from melting permafrost (Knoblauch et al, 2018), and the Arctic seabed (Stranahan, 2008). Additionally, ‘wild’ fires are not the only carbon emissions source as relate to forests, for both in the U.S., where presently the sum thereof is unaccounted for, and in regions including Europe, virgin forests are being burnt on the premise that they provide ‘renewable’ fuel. As yet, such schema account not for the possibility that forests may turn from carbon sinks to sources, nor for the ecological inter-dependencies of species that migrate between forests located across broad spatiotemporal scales, let alone the medium to long-term implications thereof.

Hence, this study and its recommendations align to a bandwidth of possible climate futures, as opposed to assuming that human action can limit mean surface temperatures to the <1.5°C increase recommended in the Paris Climate Agreement (European Commission, 2017), and the <2°C that has been cited as a benchmark more generally (Titley, 2017). A not insignificant number of Earth Systems scientists consider it more, not less probable that the scale and scope of feedback loops within the climate system could render such targets unachievable and headlines of the ilk of “Leaked U.N. climate report sees ‘very high risk’ the planet will warm beyond key limit” (Mooney, 2018), and “Global Warming’s Worst-Case Projections Look Increasingly Likely” (Temple, 2017) come as no surprise to some. “Difficult to predict”, the specificities of the spatiotemporal dimensions of ecological regime shifts, both as relate to fire and otherwise, may be (Seekell, 2016, p. 1109) the task is not necessarily “impossible”.

4.5.4 Future Firescape: Worldwide

“substantial and rapid shifts are projected for future fire activity across vast portions of the globe” Mortiz et al, 2012.

Whether mean surface temperatures rise a little or a lot the impact thereof will be spatially and temporally distributed. Having triangulated data on climatic, vegetative, and ignition patterns across several world regions, modelling by Moritz et al produced mixed results for the near-term fire trajectories of 50% of terrestrial landscapes, but a “pronounced” increase in the period 2070 – 2099 (2012, p.15). Fire, following its fuel sources, is projected to increase at mid-to-high latitudes, as forests, responding to climate change, shift polewards (Ibid), thus aligning unto the Mid-Pliocene Warm Period scenario, as referenced above. However, wherever the three sides of the fire triangle meet in “biomass-rich areas”, fire probabilities will increase whereupon fire weather becomes more frequent (Ibid). Conversely, water-stress induced regime shifts [i.e. desertification] will reduce fire probabilities and change fire behaviour in some regions.

Both in the near and far-term future, the biome types discussed in this study [Mediterranean forests and shrublands, and temperate conifer forests] are anticipated to incur “increased fire probability across most of their area” (Ibid. p.16). Recent fire activity in Australia, Brazil, Chile, Argentina, South Africa, India, France, Portugal, Spain, Italy, Greece, Canada, and Russia, amongst other regions (Leonard, 2016; Gaworecki, 2016; de Mello, 2016; Gillis and Fountain, 2016; Boren, 2016; Upadhyay, 2016; Kelly et al, 2017; Jones, 2017; Watts, 2017; World Land Trust, 2017) mirror the trajectories as were anticipated. Analysis by Bowman et al (2017) anticipates a 20-50% increase in the number of days “conducive to extreme” wildfires in regions including the Mediterranean Basin and Southern Hemisphere in the near- term future.

4.5.5 Future Firescape: Western United States

“The record of the past climate tells us that the transition from one climate state to another is rarely a smooth process” McCarthy, 2009.

While, the fact that western wildfires now typically spread to double the size as was common during the 1970s, when, on average, the wildfire season was 75 days shorter than today (Climate Central, 2012) presents humanity with a challenge, the size thereof is but modest compared with what several studies suggest may be to come.

Analysis by the USDA (Gardner, 2014) anticipates that by 2050 national acreage burned will double that of present-day levels, rising to 20 million acres p/y, the trajectory thereof roughly correlating with earlier analysis by Spracklen et al (2009), who independently predicted a rise of 54% by mid-century. However, regional predictions vary greatly from the mean. For example, the latter’s findings suggest area burned in the Pacific Northwest will rise by 78%, whereas the Rocky Mountain region can anticipate a rise of 175% (Ibid). As discussed above, regardless of their distance to areas of human habitation, wildfires have significant impact upon regional hydrology, precipitation and weather more generally, biodiversity, and air quality, thus, should the above statistics come to pass the impact to both regional and national populations will be as diverse as they are significant.

Having examined the western U.S. charcoal record across the period 3tya – present, Marlon et al (2012) found that during the 20th century wildfire activity dropped to the lowest level since the Little Ice Age, the causation thereof fire suppression [i.e. fire fighting], of which the result was a “fire deficit” (Ibid, online). The charcoal record also evidenced that wildfire activity peaked in periods of abrupt climate change [i.e. the onset of the Medieval Climate Anomaly (MCA) of 1tya – 700ya]. Their findings suggest that in the absence of fire suppression wildfire activity during the 20th century would have been greater than at any point in the past 3,000 years, including during the MCA.

Relating the above to the case study sites, warming at a rate of 0.17°C per decade since 1948 (Chang, 2015), average spring and summer temperatures in Yellowstone National Park are forecast to increase 4.0 – 5.6°C by 2100 (Romme and Turner, 2015). The resulting combination of earlier snowmelt, a longer wildfire season, and higher temperatures is anticipated to increase the area burned annually by 600>% (Peterson and Littell, 2014). Whereas, modelling predicts that, should greenhouse gas emissions continue apace, northern California will see an increase in area burned of 100>% by 2085, with a state-wide increase of between 36-74% (Westerling et al, 2011), as mean annual regional temperatures increase by 4.5°C to the north of the state, and 4.4°C to the south (Krawchuk and Mortiz, 2012). However, seasonal variance is projected to be greater, with summer temperatures up by 6.4°C and precipitation down by 68% in northern California, and up 5.3°C in summer, with rainfall down 26% to the south (Ibid).

The variance between anticipated increases in average annual burned area in the Rocky Mountains and California is in part born of the predicted impacts to the regional fire regimes, therein fuel quantity, state, and behaviour. Hydrologically, the latter is projected to swing between wildfire and floods, the juxtaposition of which is predicted to increase by 25% in northern California, and 100>% in southern (Swain et al, 2018).

4.6 Summary: Ex igne ignis

Delving deep into wildfire’s primordial past illuminates the potentialities of its future. A complex phenomenon of which the behaviour can be understood not in the absence of interrogation of sciences that in ancient times were called ‘natural’, its role within the emergence and evolution of innumerable land-based organisms, and no less so than those of our own taxonomic lineage, could be no less fundamental.

At the apex of Earth systems, wildfire constitutes a synecological unit, which comprised both slow and fast, abiotic and biotic variables reconfigures in space and time at scales local to global, momentary to epochal. But, for all its complexity, beholden to the laws of thermodynamics and mechanics, whereupon one knows of the biochemical, physical, ecological, and atmospheric conditions in which it ignites one can anticipate the range of behaviours it may manifest.

The most heterogeneous of all the natural hazards, manifold are the means by which it is monitored, and in turn, its behaviours categorised. As relates to the latter, while knowledge of the range thereof has been essential in establishing the extent to which wildfire behaviours past, present, and possible future are understood at multiple spatiotemporal scales, the foremost relevant to the task of developing a new WUI paradigm are fire regimes, intensities, and severities.

Indigenous to the case study regions, the low-severity, mixed-severity, and high- severity fire regimes are both quantitatively and qualitatively distinct in their behaviours and ecological, and wider environmental legacies. Their spatiotemporal parameters determined by factors including climate, elevation, topography, and species tolerances thereto, the regimes observed in the ecoregions types Temperate Coniferous Forests, and Mediterranean Forests, Woodlands, and Scrubs of the western U.S., reside not in a state of stasis, but of cyclical change.

Burning at the level of ground, surface, or crown within the biomass stratum, wildfire behaviour is shaped factors including weather; topography; fuel-type, size, shape, and state, including moisture content, loading, compactness, chemical properties, horizontal continuity, and vertical arrangement. Spreading not uniformly within the landscape, in all but the most extreme cases, the low, mixed, and high severity fire regimes create ecological mosaics, therein diversity in biomass age, structure, and vulnerability to future wildfires, together with seed banks that repopulate burned areas upon wildfire’s passing.

Having coevolved with wildfire, species native to these, and other fire-prone regions exhibit a range of morphological, biochemical, physiological, phenological, and/or behavioural traits that enable them to coexist within historical fire return intervals, intensities, and behaviours more generally. Functionally classifiable as either fire- tolerant or fire-resistant, fire-adapted biota exhibit one of three primary ‘modes of persistence’ (Rowe, 1983):

Regenerating through their perennating parts and seedling recruitment, endurers, such as Canyon live oak, have evolved traits that enable them to persist in low to mixed severity fire regimes that return with frequency, but relatively low intensity.
Though parent plants succumb to fire, evaders, such as Lodgepole pine, have evolved traits that enable them to persist in mixed to high severity fire regimes, where their seedlings rapidly repopulate the nutrient abundant post- fire landscapes.

• Protected by an array of pyro-armoury and defence behaviours, such as thick bark and biochemical mechanisms, resistors, such as Ponderosa pine, have evolved traits that enable them to persist in low to mixed severity fire regimes of relatively high frequency.

The foremost functional traits exhibited by fire-resilient species are pyriscence [fire- stimulated seed release], pyrogermination [fire-stimulated germination], abscission [shedding of parts], retardant rhytidome [thick/plated bark], and resprouting [re- colonisation through cloning].

While many are the fire-adapted faunal species on Earth, descendants of the superfamily Hominoidea, humans, are the foremost. Having stepped bipedally-forth from the forest to the geologically recent East African plains in the Mid-Late Miocene, our ancestors increasingly integrated fire in to the various facets of their lives. They followed fire. They foraged fire. They forged fire. Upon doing so they left archaeological, anthropological, physiological, genealogical, and other biological fragments which, collectively, illuminate our coevolution with fire.

Ab antique, wildfire and its regimes have followed the rhythm of the seasons, which reconfiguring in epochal time, ‘dance’ not to the tune of mere mortals. Whether MST increases by 1°C, 2°C, 3°C, or more, de futuro, within both the case study regions, and other Mediterranean and temperate forests, woodlands, and scrublands worldwide, theoretical and computer modelling suggests wildfire frequencies will increase.

Put succinctly, as Cedric Price may have said, before long it appears a very many more that live both within and beyond the wildland urban interface are about to become members of a very ‘Hot Stuff Club’. Might the wildland urban interface of 2030, 2050, or 2070 look like a still from Nebraskan architecture graduate Joshua Puppe’s ‘The Authors’ visual story [Fig. 42] and, more generally, how might humanity’s relationship with fire develop in the decades to come?

4.7 Homo ignis: a flash fiction

Leaning forward, toward the flames, tentatively they lit the fennel stalk. Its light shining bright under a sky of many stars, it illuminated their path ahead. About them, creatures of the night kept their distance, watching in wonder at fire captured. Passing the torch from one to another, they marvelled at its potency. Feasts and beasts sprung forth from its flames, nurturing their bellies and their minds. Igniting their alchemical endeavours, it endowed them powers magical. Their torch held aloft, they travelled to the far corners of the world, and then to the stars under which they once stood.

Footnotes

[108] In reference to Edward Lorenz’ Chaos Theory concept the Butterfly Effect (Gleick, 1998).