Introduction to prescribed fire

INTRODUCTION TO

PRESCRIBED FIRE

Prescribed fire—the intentional use of fire by humans—has been a universal practice of cultures for millennia. In this extract from their book, Global Application of Prescribed Fire, Scasta and Weir describe the use of this technique and the impact and implications it has on society and the environment.

JOHN DEREK SCASTA AND JOHN R WEIR

Below Application of prescribed fire under very specific weather, fuel and preparation conditions with a variety of ignition tools, including lighting brush piles with a drip torch. Fire is often viewed as a contradiction. It has the power not only to destroy, but also to stimulate. Fire evokes fear in people, while simultaneously stimulating intrigue and fascination. Fire has facilitated the development of cultures, societies and industries, yet it has also destroyed infrastructures and lives (Pyne, 1997; Brown et al., 2009).

The importance of fire for ecosystems worldwide has been compared with soils, water and climate and their prominence as ecological drivers (Bond and Keeley 2005). Although the effects of fire are universal, they can be locally variable and are often strongly influenced by humans—from both a suppression and ignition perspective (Parisien et al., 2016). Importantly, fire cannot and should not be thought of independently without considering the integrative influence of humans and, particularly, human use of fire (Coughlan and Petty, 2012).

Finally, to begin to untangle the fear and contradictions, it is necessary to distinguish between wildfires and those fires that are intentionally set by humans.

PHOTO: DEREK SCASTA

Origins of prescribed fire

The intentional use and application of fire by humans is often referred to as ‘prescribed fire’, ‘controlled fire’ or ‘cultural fire’. For each term, ‘burn’ or ‘burning’ is often used interchangeably with ‘fire’ (i.e. ‘prescribed burn’ or ‘cultural burning’).

Historically, regardless of the terminology or local vernacular, these fires were lit with specific objectives and under certain conditions (Weir, 2009), with both objectives and conditions being determined before any ignition. The objectives could be to reduce hazardous fuels or to structure habitat features for a specific organism. The particular conditions could include specific weather—such as low relative humidity or low wind speeds—or specific preparations—such as the installation of a certain type of firebreak (e.g. a mowed or ploughed bare soil line).

The word ‘prescribe’ has foundations in the medical terminology and is an indication that an authorised professional advises the application of a treatment in order to achieve some beneficial result (Merriam-Webster, 2020). The origin of the word comes from the Latin praescrībere (with derivations from late Middle English c. 1425–75) meaning ‘to direct in writing’, which is an indication that the recommendation from the authorised professional be explicitly provided in written form (Merriam-Webster, 2020).

Although the applications of prescribed fire are inherently variable, it is the following key features that are consistent: „ some form of authority indicating fire use „ an a priori strategy for planned execution „ the common practice of some organised and available plan typically expressed verbally and/or in writing „ clearly identified objectives and conditions.

Certainly there are varying opinions about the acceptability and application of prescribed fires. These opinions are influenced by concerns about smoke, risk and competing objectives (Tiedemann et al., 2000; Williamson et al., 2016).

However, whether a region wants prescribed fire may be a moot point because that region likely has had wildfires burning across the landscape at some point in time, regardless of whether the fires were desired or not. Functionally, the flammability of the landscape and the risk of wildfire must be considered in developing prescribed fire programs. Moreover, evidence suggests there may be increasing public support for prescribed fires (Gardner et al., 1985).

The book

The book Global Application of Prescribed Fire endeavours to provide globally relevant examples of firsthand application, techniques, local issues and methods of prescribed fire use. From lighting fires with sticks to ignition from an unmanned aerial vehicle (or drone), the ways in which fire is applied to the land is as diverse as our many cultures.

Each chapter in the book presents a diversity of views and uses of prescribed fire. No other book, to our knowledge, has presented the definitive application of prescribed fire, including why, when and how prescribed fire is used in ecologically and socially unique regions of the world. Such a global perspective, particularly with a focus on human applications of prescribed fire, is of utmost importance because, as stated by Bowman et al. (2009), “An Earth system perspective is essential to understanding how fire has developed throughout Earth history, and

teasing apart the direct and indirect interactions between humans and fire.”

Although there are numerous books about fire ecology that have a global perspective, this book is not focused on the successional impacts of fire in a particular region or ecosystem, but rather the specific logistics, constraints and social dynamics surrounding the intentional human application of fire.

Moreover, this book is not a prescribed fire manual intending to instruct on how to burn (if that is what you are seeking, see Weir, 2009); rather, this book provides fire practitioners—both neophytes and seasoned veterans—with key ecological and managerial insights into how prescribed fires are conducted around the world. Such a global assessment and quantification, with the inclusion of the social aspects of prescribed fire application, will allow each reader to discover a newfound knowledge about what is possible with fire relative to a broad spectrum of cultures, constraints and objectives.

Given escalating fire regimes, changing climate patterns, burgeoning human expansion into wild areas and the intensification of land use, such information is extremely timely and needed (Westerling et al., 2006). This book will enhance understanding and knowledge of the application of prescribed fire at a global scale in a way that has not been done before and at a time when such practical application could not be more important. We believe it will be the impetus for a global conversation about how fire as an ecological driver of disturbance, as well as a management tool, can be restored in the Anthropocene (i.e. the current geological age, when human activity has been the dominant influence on climate and the environment) for the benefit of society and the Earth simultaneously.

The editors and authors of the book aspire to accomplish four objectives with this ambitious publication: 1. to explore new techniques, ideas and thoughts on how to apply prescribed fire from a global perspective 2. to provide regional case studies that present the local nuances and metanarratives that constrain or enhance prescribed fire projects 3. to stimulate cross-cultural conversations about how fire should, could or would function in ecosystems with a broad gradient of fire regimes, dependencies and objectives 4. to relate prescribed fire with novel wildfire regimes that are emerging globally with implications for the protection of life and property, as well as sustaining unique firedependent flora and fauna and fire cultures.

Extract reproduced with permission from Global Application of Prescribed Fire, edited by John R Weir and J Derek Scasta. Published in Australia and New Zealand by CSIRO Publishing, 2021.

Above Lighting grassland with a drip torch and a combination of mowed and ploughed lines.

Inset left Lighting understorey vegetation in a forested system with a terra torch.