Does Hazard Reduction Burning Prevent Bushfires?

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Hazard reduction burning is a valuable tool in the arsenal of wildfire management strategies. While it has proven effective in reducing the intensity and spread of wildfires, its success is contingent on various factors, including the rate of fuel accumulation, spatial optimization, and the integration of indigenous fire management practices. Addressing the operational, social, and ecological challenges associated with prescribed burning is crucial for enhancing its effectiveness in preventing bushfires.

Bushfires are a significant environmental and social issue, particularly in regions like Australia and the Western United States. One of the primary methods proposed to mitigate the risk and severity of bushfires is hazard reduction burning, also known as prescribed burning. This article explores the effectiveness of hazard reduction burning in preventing bushfires, drawing on various research studies to provide a comprehensive overview.

The Concept of Hazard Reduction Burning

Hazard reduction burning involves the deliberate burning of vegetation under controlled conditions to reduce the amount of fuel available for potential wildfires. This method aims to decrease the intensity and spread of future fires, making them easier to control and less destructive.

Effectiveness of Hazard Reduction Burning

Research indicates that hazard reduction burning can be an effective tool for wildfire management. Studies have shown that prescribed burning can reduce the intensity, size, and damage of wildfires, thereby facilitating fire suppression efforts. However, the effectiveness of this method is often limited to a short post-treatment period of 2-4 years due to the rapid accumulation of fuel.

In the Western United States, prescribed fire is considered one of the most effective means of reducing wildfire hazard and restoring ecological function to fire-adapted ecosystems. Despite this, the adoption of prescribed burning practices has been insufficient, particularly in the Western US, where fire activity has increased in recent decades.

Challenges and Limitations

While hazard reduction burning has its merits, it also faces several challenges. Operational, social, and ecological issues can constrain the effectiveness of prescribed fire. For instance, the optimization of the spatial pattern of fire application is critical but has been poorly addressed by research, and practical management guidelines are lacking.

Moreover, the increasing urbanization at the urban-bushland interface poses additional challenges. The development of residential areas adjacent to bushland increases the demand for resources to protect these environments, complicating hazard reduction efforts. Legislative changes and planning controls have been implemented in some regions to streamline the process of environmental impact assessment for bushfire hazard reduction works, but the effectiveness of these measures remains to be fully evaluated.

Indigenous Fire Management Practices

Indigenous fire management practices, such as cool burning, offer valuable insights into bushfire mitigation. Cool burning involves lighting low-intensity fires during the early dry season to reduce fuel loads and create fire breaks, thereby preventing larger, more destructive fires later in the season. These practices not only reduce the risk of bushfires but also maintain and protect habitats for various species.

 


Does hazard reduction burning prevent bushfires?

Joshua M. Johnston has answered Unlikely

An expert from Canadian Fire Service in Forestry Sciences

Wildfires occur and reoccur at a semi regular timestep for a given ecosystem. Once an area burns there is a timelag until it is able to burn again (which depends on the ecosystem, and the timing and severity of the initial burn). So, if you were to completely burn a piece of land (remove all vegetation from it), that resets the clock and there is a period of time when it cant burn again. BUT, hazard reduction burning often doesn’t aim to fully consume all of the vegetation (just reduce the build up of it, particularly on the forest floor), as a result you cant really say that it will “prevent” fires from occurring in the treated area.

What you can say about hazard reduction burning is that it reduces the available fuel for future fires, thereby “reducing” the intensity of fires in that area over a situationally dependent timelag following the treatment. This is an important contribution as lower intensity fires are generally easier to suppress. However, this is also situationally dependent and should be considered on a case by case basis.

I am aware that some people may believe there is a correlation between hazard reduction burning and decreased fire activity because years with increased reduction burning often are also years with far less wildfires requiring suppression. This is actually an incorrect conclusion, it is actually an inverse relationship. What really happens is that in years with less wildfires to suppress, you have a lot of fire fighters and surplus resources/money available and as a result this allows fire managers to conduct more of the hazard reduction burning they have been planning. In years when the suppression end of things is very busy, you don’t have a lot of spare people/money to conduct hazard reduction burns.

 

Does hazard reduction burning prevent bushfires?

Crystal A. Kolden has answered Extremely Unlikely

An expert from University of Idaho in Fire Science

The key word here is ‘prevent’. Hazard reduction burning does not ‘prevent’ fires by reducing the number of fires to zero. There will always be ignitions, and there will always be some kind of vegetation that grows, so there will always be bushfires. 

Hazard reduction burning (also called intentional burning or prescribed fire here in the US) simply reduces the amount of vegetation and biomass available to burn. The effect of this is that when a fire does ignite (not ‘if’ but ‘when’) there is less fuel for the fire, and thus less intensity, lower flame lengths, and less potential for bushfire disasters. 

In some places globally, hazard reduction burning can actually increase the frequency of fires because it induces grasses to grow in some ecosystems. So there are more fires, but (again) they are lower in intensity and there is less potential for disaster and destruction). A good example of this is the African savannah, which has the highest fire frequency in the world.The grasslands are maintained by frequent fire, and while there is a LOT of fire, there are almost no disasters. 

 

Does hazard reduction burning prevent bushfires?

Francisco Moreira has answered Unlikely

An expert from University of Porto in Ecology, Environmental Science, Biology

If “preventing” means “not burning”, then it is quite UNLIKELY that hazard reduction prevents wildfires. But it does reduce fire intensity and therefore fire damage, and that is the more important. Check the paper we wrote on the situation in Mediterranean-type climates, and how the success of wildfire policies should be evaluated:

https://iopscience.iop.org/article/10.1088/1748-9326/ab541e

Note, however, that in Figure 1 of the paper, the association between burned area and fire weather is weaker in Western Australia, which does suggests a fire-management mitigating effect, namely the extended prescribed burning program in place.

 

Does hazard reduction burning prevent bushfires?

Philip Gibbons has answered Unlikely

An expert from Australian National University in Forestry Sciences, Ecology, Disaster Management

This is a complex question and I recently shared my views on it for The Canberra Times here.

 

Does hazard reduction burning prevent bushfires?

Nuno Guiomar has answered Unlikely

An expert from University of Évora in Disaster Management, Plant Ecology

In fire-prone ecosystems, the main objective of the fire prevention should never be placed on the fire exclusion, since it is unrealistic, useless and will allow the creation of conditions for the development of fires with behavior above the suppression capacity, more severe and larger in size. Fuel management must be planned to fulfill two critical objectives: a) create opportunities for the suppression, allowing the reduction of the (potential) fire intensity and the fire rate of spread in adverse weather conditions, and b) reduce fire severity. This implies that fuel management programs must be designed at the landscape scale to undertake management actions in the forest patches, taking into account extreme fire behaviour scenarios. Moreover, fire prevention must not be limited to the protection of infrastructures since they will not have significant effects either on the fire behaviour or on the protection of the infrastructures themselves. The fuel management programs carried out in Western Australia seems to be successful, and should be extended to other regions of the country.

 

Does hazard reduction burning prevent bushfires?

Fillipe Tamiozzo Pereira Torres has answered Unlikely

An expert from Federal University of Viçosa in Ecology

The prescription for the use of fire is like the medical prescription. Making the analogy between both, the technician trained in the use of fire similar to the doctor, and according to the patient’s conditions, in this case the landscape, observes and analyzes a set of symptoms presented by the patient / landscape which will translate into a diagnosis . After the diagnosis phase, a treatment is prescribed, which is detailed in an official document – the Integrated Fire Management Plan – MIF (our “medical prescription”) – how it should be applied, that is, the conditions, the “doses ”And the period of our treatment. Given the state of vulnerability of our patient – the landscape – preventive treatment can be applied, in order to increase the resilience of the landscape and reduce the disturbance caused by a potential fire.

The prescribed fire, being a fire that seeks to reproduce a fire of natural origin, works as a vaccine for a landscape with an increasingly weakened immune system (by depopulation, by the aging of the population, by the loss of land uses), with a high load of available and vulnerable fuel in the context of climatic fluctuations. Obviously, there are other treatments, such as mowing, be it manual or mechanical, or even more invasive treatments such as chemicals. The MIF is a very effective and efficient “vaccination” program (cost vs benefit), but always depending on the conditions of our “patient”.

 

Does hazard reduction burning prevent bushfires?

Daniel Moya has answered Unlikely

An expert from Universidad de Castilla-La Mancha in Forestry Sciences, Plant Ecology

The need for resilient landscapes to face catastrophic forest fires must include diverse perspectives. The new holistic paradigm for forest fire risk management should be based on the creation of resilient territories that more effectively integrate the social and economic conditions of the territory in fire prevention. It should include analysis of experiences, lessons learned and knowledge gaps identified to answer the questions:

What are the components of a resistant landscape to forest fires?

What political and technical actions are necessary to manage them?

How much and how will the rising suppression costs borne by public agencies be reduced?

How to effectively address socio-economic factors that increase the risk of catastrophic forest fires?

What opportunities exist and how to encourage private owners and land managers to develop collaborative fire risk mitigation strategies?

The global overview of fire risk reduction approaches at landscape level must include social and economic aspects in the prevention of catastrophic fires, however never pointing for the total exclusion that leads to the fire paradox “success in suppression promotes devastating fires”

The point will be the research to learn how to integrate prevention and suppression in the landscape scale to achieve sustainable fire regime, both social and ecological.

 

Does hazard reduction burning prevent bushfires?

Alexandro B Leverkus has answered Unlikely

An expert from University of Granada in Ecology

Fires of the magnitude of those recently seen in Australia are extremely unlikely to be prevented through prescribed burning or any kind of land management.

One key factor leading to these large, intense wildfires is the increasing prevalence of drought, which creates enormous amounts of extremely dry fuels –e.g., by drying the dead vegetation, by killing plants that then become dry, and by reducing moisture in the upper soil layers. Consider the effort it takes to lit a campfire with green branches cut from living trees, compared to dry branches collected from the ground. The high moisture in the first leads to much slower progression of the fire. This can be upscaled to landscapes, in which fire is faster in its spread the drier the fuels. Faster spread means that wildfire very quickly becomes difficult to contain (imagine trying to contain the flames that escaped your campfire and slowly move away through green grass, and compare that to fire moving fast over dry grass). This means that the burnt area very quickly becomes very large (you wouldn’t know where to focus your attention to try to stop it) and very intense (i.e., hotter, because more fuel is burning simultaneously, so you would need a greater effort in turning it off at any given spot). So, even though reducing some fuels through hazard-reduction burns can reduce fire intensity locally, this is very unlikely to prevent fire progression under extreme drought unless the fire happened to be ignited in the hazard-reduction area (i.e., if you had put fewer twigs inside your campfire and reduced the dry grass around it) and the fire is quickly contained –an unlikely scenario at the landscape scale because nobody knows where a fire will start.

Additionally, fuel-reduction burns are even less effective in preventing fires because fires generally occur in the so-called “fire season”, which is the period during which drier fuels are coupled with fire-prone weather. This is when atmospheric moisture is very low, temperatures are high, and wind feeds the flames with oxygen.

With such considerations, it is not difficult to see that changes in large-scale climatic patterns are likely behind extreme fire behavior. Ongoing changes in precipitation regimes and hotter climate in many places (which also produces drier ecosystems due to greater evaporation) are expanding the fire season in time (making it longer) and in space (getting to unprecedented places) and making fires more intense and difficult to contain, and thus larger, and so on.

So, is hazard-reduction burning completely useless? No. There are many potential benefits from it. For instance:

  • Locally, it can lead to a smaller intensity of fires in treated areas, which may enhance the possibility for recovery
  • It increases the prevalence of fire-adapted vegetation and hence speeds up regeneration
  • It promotes the persistence of certain habitat types and many species that depend on open landscapes and fire-driven dynamics
  • In some cases it could buffer the spread of fire to particular areas
  • It can be effective in slowing down fire progression and enhancing the likelihood of quick contention, but under less extreme weather and fuel-dryness conditions

As a conclusion, management that has traditionally helped to prevent large-scale wildfires may be turning less effective under climate change, and the unprecedented scale and magnitude of recent wildfires is likely regardless of such management. While prescribed burning can still provide many valuable outcomes, we must think of additional means of addressing the pressing, novel ecological and human risks related to wildfires, and we must tackle the larger-scale causes underlying them. In short, fire management could be becoming less a local-scale land-management issue than a global policy one.

 

Does hazard reduction burning prevent bushfires?

John D. Bailey has answered Unlikely

An expert from Oregon State University in Forestry Sciences

Nothing can prevent bushfires (or wildfires, as we call them in the States); as long as there are fuels out there and hot/day weather, any ignition can lead to a fire… and some will get big if it is particularly hot/dry/windy and if the fuels are abundant and continuous. 

Treating the fuel hazard lowers the intensity of the burning, so it raises the probability that the fire doesn’t spread as fast and/or that it can be put out. It also raises the probability that when it encounters something of value, less damage is done. Hence, treating the fuel hazard consistently lowers bushfires “risk” even though it cannot prevent all of them.

 

Does hazard reduction burning prevent bushfires?

Camille Stevens-Rumann has answered Uncertain

An expert from Colorado State University in Forestry Sciences

It is a bit more complicated than a yes or no. It can help prevent the spread of a bushfire for a few years after burning but would not stop them all together or for an indefinite period of time. Vegetation grows back, sometimes fairly quickly which can decrease the amount of time hazard reduction burning is effective. Also extremely dry weather may allow for bushfires to burn through areas already treated.

 

Does hazard reduction burning prevent bushfires?

Maria Polinova has answered Likely

An expert from Haifa University in Fire Science

Cleaning dead matter (litter) clearly reduces fire risks in wildlands. Hazard reduction burning is one of the convinient approaches for dead fuel reduction. However, in addition to the short-term positive effect of this method it should be consideedr the long-term effect on the ecosystem. Systematic burnings changes vegetation compositon by reducing the number of perennial plants resistant to fires. Thus, regular burnings in the long-term period increases the ignitiobility of areas.

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