
Philip ZylstraCurtin University · School of Molecular and Life Sciences
Philip Zylstra
B.App.Sc Environmental Science, PhD
About
56
Publications
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Introduction
My focus is on the drivers of fire behaviour and the way that they translate into decision-making concepts such as risk or the notion of flammability. To this end I have developed a process-driven model that gives detailed, dynamic fire behaviour predictions by calculating the capacity for flame to ignite new leaves, branches or plants across the spaces between them, as determined by the leaf traits of the component plants. Details of this model are in my thesis, with papers in progress.
Publications
Publications (56)
Floral fire ecology incorporates a feedback loop in which plants influence fire behaviour and fire behaviour influences the flora. Recent advances in fire behaviour modelling have quantified many plant‐based drivers of fire behaviour, but the consequent ecological effects of this have not yet been adequately modelled mechanistically.
Here, I introd...
As climatic changes continue to drive increases in the frequency and severity of forest fires, it is critical to understand all of the factors influencing the risk of forest fire. Using a spatial dataset of areas burnt over a 58-year period in a 528,343-ha study area, we examined three possible drivers of flammability dynamics. These were: that for...
Forest wildfire impact is widely believed to increase with time since disturbance, presenting a dilemma for the persistence of fire‐sensitive species. However, in south‐western Australia, disturbance has been shown to increase wildfire likelihood for some decades before it again declines. It has been proposed that this trend occurs through ‘ecologi...
Historically unprecedented areas of forest habitat have been impacted by fire, as climate change and other anthropogenic disturbances drive increases in fire burned area and severity. Although 88% of Australia's [threatened] land mammals are threatened by inappropriate fire regimes, calculations of animal mortality resulting from specific events ha...
Prescribed burning is a key tool in land management globally used to reduce wildfire risks and achieve ecological, cultural and resource management objectives across both natural and human systems. Despite its widespread application, research on prescribed burning is marked by significant gaps. Subsequently, we posed the following research question...
Empirical evidence in scientific literature shows that forest flammability in south‐western Australia declines as forests recover from disturbance, indicating that current policies mandating disturbance may be counterproductive. Zylstra et al. (2023) used mechanistic modelling to explain this trend in Red Tingle (Eucalyptus jacksonii) forest in sou...
Despite the importance of protecting forests and woodlands to achieve global climate and biodiversity goals, logging impacts persist worldwide. Forestry advocates often downplay these impacts but rarely consider the cumulative threat deforestation and degradation has had, and continues to have, on biodiversity. Using New South Wales (Australia) as...
Our previous analysis of mapped records of forest fires in National Parks in Southwestern Australia showed that fires initiated a pulse in flammability (the likelihood of a point being burned by wildfire), but that flammability declined as forests matured (Zylstra et al 2022 Environ. Res. Lett. 17 044022). This reduction in flammability was contrar...
There has been extensive commentary about historical First Nations' land management in Australia, including in tall, wet forests, and therefore their condition at the time of the British invasion in 1788. Popular texts have interpreted records kept by early British invaders to argue that extensive areas of tall, wet forest were kept open through fr...
Many forest types globally have been subject to an increase in the frequency of, and area burnt by, high‐severity wildfire. Here we explore the role that previous disturbance has played in increasing the extent and severity of subsequent forest fires. We summarise evidence documenting and explaining the mechanisms underpinning a pulse of flammabili...
Fire is a key ecosystem process with more than half the world's land surface potentially subject to fire. A key aspect of fire ecology is the fire regime, with fire frequency an important component. Fire frequency appears to be increasing in some ecosystems, but decreasing in others. Such temporal and spatial variability in fire frequency highlight...
Despite the importance of safeguarding forests and woodlands for achieving global climate and biodiversity agendas, logging continues across most forested countries. Forestry advocates often claim logging has minimal impacts, but rarely consider the cumulative threat deforestation and degradation has had, and continue to have, on species. Using New...
Wildfire risk-management needs to consider interrelated factors that influence fire regimes, including changing climate and sometimes conflicting stakeholder priorities. With wildfires increasing in size and intensity over recent decades, wildfire risk management is becoming more important and more complex. For southwest Australia, wildfire risk-ma...
Cooperating with forests could hugely reduce bushfire risk, even in a changing climate
Many forests regulate their own flammability, creating environments that make bushfires far less likely – unless they are interrupted.
The newly published finding in the journal Environmental Research Letters answers long-held beliefs that forests must be burned...
The Bendethera Shrublands are a unique and fascinating ecological community restricted to less than 100 hectares on a series of steep limestone outcrops in the Deua River valley. The community is characterised by a dense shrub layer to around 7.5 metres height and dominated by Acacia covenyi, a locally endemic species, whose blue foliage forms a st...
Research highlights—Feedbacks between fire severity, vegetation structure and ecosystem flammability are understudied in highly fire-tolerant forests that are dominated by epicormic resprouters. We examined the relationships between the severity of two overlapping fires in a resprouting eucalypt forest and the subsequent effect of fire severity on...
Globally, collapse of ecosystems—potentially irreversible change to ecosystem structure, composition and function—imperils biodiversity, human health and well‐being. We examine the current state and recent trajectories of 19 ecosystems, spanning 58° of latitude across 7.7 M km2, from Australia's coral reefs to terrestrial Antarctica. Pressures from...
ContextFire behaviour research has largely focused on dry ecosystems that burn frequently, with far less attention on wetter forests. Yet, the impacts of fire in wet forests can be high and therefore understanding the drivers of fire in these systems is vital.Objectives
We sought to identify and rank by importance the factors plausibly driving flam...
The historical response to multiple tragic fire events has been to hold inquiries that invariably recommend an increase in existing mitigation efforts. In light of the scale of the current bushfire crisis, however, a genuine scientific response requires that we no longer simply attempt more of what we have always done, but that we question whether...
Provides a brief summary of the response of PLoS One to the memo by Cruz and Sullivan criticising my paper.
It is widely assumed that long unburnt forests are the most flammable areas; this research found that the opposite was true for forests of the Australian Alps.
It has been widely accepted that bushfire risk increases with time since fire, reflecting the accumulation of fuels. The link between fuel load and fire risk is however tenuous, dependent on grey literature and frequently at odds with the peer-reviewed material. This is problematic, as the question of flammability dynamics is fundamental to our cur...
For decades, forest flammability has been linked to fuel load – the weight of fine twigs, leaves, and bark in a forest. Accordingly, the paradigm of fuel reduc- tion by burning has pervaded Australian thinking, providing a single answer to every question of fire risk reduction. At its core however lies only a rough theory described by the author as...
Fire can considerably increase the landscape's vulnerability to flooding and erosion, which is in part caused by fire-induced soil heating, vegetation removal and resulting hydrological changes. While the magnitude of these fire effects and ecosystem responses is frequently studied, there is still little attention for the fundamental mechanisms tha...
Overview Cruz and Sullivan provide a series of assertions about our paper [1] (modified version posted at http://journals.plos.org/plosone/article/comment?id=10.1371/annotation/1e5e9d98‐5e72‐4e34‐ ae56‐2538704be8ce), which attempt to cast doubt on the overall validity of our study and the Forest Flammability model. Here we examine, in turn, the sub...
The revegetation of cleared landscapes with woody plants (termed “environmental planting”) has the potential to sequester carbon (C), provide habitat, and increase biodiversity and connectivity. These environmental values are potentially offset by an increased fire hazard posed by revegetation. There is a need to understand the influence environmen...
The influence of plant traits on forest fire behaviour has evolutionary, ecological and management implications, but is poorly understood and frequently discounted. We use a process model to quantify that influence and provide validation in a diverse range of eucalypt forests burnt under varying conditions. Measured height of consumption was compar...
Ignition process in the FFM.
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Sub-models used in the FFM for this study.
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Model overview.
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Species leaf traits used in the FFM for this study.
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Processes in one time step.
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Donor flammability.
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Plant and flame traits, and resultant heating as shown in S2 Fig.
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Observed and predicted flame heights.
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Numerous studies have attempted to address the utility of LiDAR as a tool for measuring fuel inputs to fire behaviour models, however the direct effect of this approach on fire behaviour prediction requires quantification. We used a biophysical, mechanistic model validated for eucalypt forest in SE Australia to assess the improvement in prediction...
Live fuel moisture content (LFMC) is a parameter that affects the flammability of plants, and the capacity to measure it remotely makes it an accessible variable for use in fire behaviour models. Although the effect of LFMC on the flammability of fuel particles has clear theoretical support however, the way in which this relates to fire behaviour i...
Numerous factors have been found to affect the flammability of individual leaves and plant parts; however the way in which these factors relate to whole plant flammability, fire behaviour and the overall risk imposed by fire is not straightforward. Similarly, although the structure of plant communities is known to affect the flammability of the sta...
It is widely assumed that regardless of the community in question, recently burnt forests are less flammable than long-unburnt areas, so that the fire-flammability feedback is negative. An alternative hypothesis has been proposed for Snowgum forest/woodland based on deterministic fire behaviour modelling, describing a positive feedback where mature...
Australian Standard AS 3959_2009 provides a methodology for estimating the amount of heat that a bushfire flame will radiate onto a structure, however it does not factor in the role that vegetation has in blocking some of that incident radiation. This report addresses that shortfall.
The obscuration profile of the vegetation is calculated from the...
Wildland fire has considerable influence on both natural and anthropogenic environments and consequently, the ability to understand, predict and manage it has become a growing priority as human populations have increased their influence upon and awareness of the natural, fire prone environment. Despite this, in Australia a disconnection and failure...
'Flammability' means different things to different people. Scientifically, it can be defined through three component variables that describe how well the fuel ignites (ignitibility), how well it burns (combustibility) and how long it burns (sustainability). The 'fuel' may be a plant organ, a whole plant or a plant community. While the terms ignitib...