Logging burns conceal industrial pollution in the name of ‘community safety’

| May 18, 2018

Earlier this year, Melbourne and large areas of Central Victoria, experienced days of smoke haze and poor air quality warnings as a result of planned burns. It’s a regular event occurring every autumn.

This smoke has been reported by both government and media outlets as largely the result of planned burns to reduce bushfire risk, along with agricultural burn-offs and increased use of wood heaters.

But this is only part of the story. A good proportion of the smoke this autumn has actually come from the intensive burning of debris left behind after clearfell logging. This is essentially industrial pollution.


Smoke Haze over Mooroolbark and Melbourne’s eastern suburbs on Tuesday 1 May 2018, shortly after the time when the Poor Air Quality Index reached 901.

Industrial clearfell logging vs fuel reduction

To understand why clearfell logging burns are different compared with planned burns to reduce bushfire risk, we need to understand clearfell logging, which involves cutting most or all of the commercially valued trees in one single operation across a designated area (called a “coupe”).


Large volumes of forest biomass are left on the ground following clearfell logging in the Mount Disappointment State Forest with the Melbourne City Skyline in the background, August 2010.

In the process of clearfell logging, understorey vegetation is usually pushed over. Along with tree heads and branches left behind after logging, large volumes of debris – known as “slash” – are created. This is partially removed by applying a high intensity burn across the coupe, which in turn establishes an ash seed bed for the next crop of trees to be established. Generally, around 90-100% of the coupe is burnt.

In contrast, planned burns to reduce bushfire risk (otherwise referred to as fuel reduction burns) are less intense. They mostly target “fine fuels” (vegetation less than 6mm in diameter) on the forest floor and in the understorey, which may average around 15 tonnes per hectare (t/ha).

Burn coverage is usually 50-70% of the site.


Surface and understorey ‘fine fuels’ targeted in a recent low intensity burn near Mt Dandenong in April 2018.

Clearfell logging burns consume much larger volumes of vegetation biomass in the form of tree heads, branches, bark and downed understorey vegetation. According to a report completed for the National Carbon Accounting System, clearfell logging burns consume, on average, 130 t/ha of slash in mixed-species forest and 140 t/ha of slash in Mountain Ash forests. This means that, while clearfell logging burns cover much less ground than fuel reduction burns, they burn far more biomass per hectare – generating far more smoke.

The list of planned burns on Forest Fire Management Victoria’s website showed that, at the beginning of May, 77 of the 119 burns either lit or planned to be lit across the Central Highlands of Victoria and surrounding areas were on logging coupes.

These burns were individually lit over a period of weeks, with some days predominantly logging burns, others fuel reduction burns. An example when logging burns were prominent occurred on April 20 this year, where 10 out of 12 planned burns were observed as occurring on logging coupes.

Using a simple calculation based on average biomass consumption, fuel loads and burn coverage for logging and fuel reduction burns, we estimate that up to 99% of biomass burnt most likely occurred on logging coupes. The following day, the Environmental Protection Authority observed “poor” air quality at multiple air monitoring stations across Melbourne due to smoke.

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MODIS Rapid Response Terra Satellite image taken 20 April 2018 showing the smoke intensity of the logging burns. – NASA 2018

Even on days when the majority of burns lit were for fuel reduction, planned logging burns still contributed a proportion of biomass burned. For example, on April 30, only three out of 12 planned burns were observed as occurring on logging coupes, but they may have contributed to around one-third of the total biomass burned.

Likewise, on the following day, the Environmental Protection Authority observed “very poor” air quality across multiple air monitoring stations. While multiple planned burns contributed to this pollution event, we contend that logging burns increased the levels of pollution in addition to the smoke originating from fuel reduction burns.

The key issue here is that not all “planned burns” are equivalent. Fuel reduction burns are intended to reduce the bushfire risk to lives and property. Indeed, work led by The Australian National University shows that regular fuel reduction burns can reduce risk to properties if carried out within close proximity.

In contrast, clearfell logging burns are part of an industrial process that extracts pulp logs and sawlogs for commercial sale to private enterprise. They play no part in reducing bushfire risk to life and property. Actually, the reverse is true: logging makes forests more prone to subsequent high-severity crown-consuming fires with associated risks to communities.

Given that a substantial proportion of the recent smoke over Melbourne and surrounding regional Victoria likely originated from logging burns, could that smoke be deemed industrial pollution? This is a valid question, given the serious health impacts associated with smoke pollution.

The ConversationLogging burns would not be needed (and a substantial amount of associated smoke not generated) if the forest had not been logged in the first place. It is imperative that government departments inform the public about the smoke pollution coming from logging operations, whose purpose is for private commercial gain.

This article was written by Chris Taylor, a researcher at the University of Melbourne and David Lindenmayer, a Professor at The Fenner School of Environment and Society in the Australian National University. The photos were taken by Chris Taylor. The article was originally published on The Conversation. Read the original article.



  1. Max Thomas

    Max Thomas

    May 19, 2018 at 3:52 pm

    Air quality was very poor in many places around Victoria during the Autumn of 2018. It was the predictable result of government-approved fuel reduction burns and private burning off. Dr Chris Taylor informs us here that we can add the burning of logging debris to the list.

    The pending charges against the operators of Hazelwood power station are that it allegedly changed the atmosphere during the Morwell fire so that the air became hazardous to the health, welfare and safety of humans. If the poor air quality this Autumn had been caused by emissions from a mine or power station there would be outrage about the impact on health and there would be calls for government action.

    Warnings from the EPA and health authorities confirmed that the risk to health from burning off is real. I suggest also that ‘cool’ burns probably emit substances that are likely to be more harmful to health than those emitted from other sources which have more complete combustion at much higher temperatures.

    Expert opinion isn’t unanimous on the best approach to reducing the risk of wildfires. Regrowth can result in drier soils with increased and more volatile fuel loads. Some even argue that burning off tends to establish a self-perpetuating pattern; a kind of ‘eco-porn’ that once started tends to become addictive.

    But changing seasonal conditions are likely to throw doubt on present assumptions in any case. We’re always well prepared for the battles of the past but not so good at adapting to changing circumstances. If we keep doing the same things how can we expect different results?

    It looks like there are competing forces within government with those who support burning off prevailing. There is little evidence that the health risks are taken seriously until it becomes apparent to everyone and casualties begin to appear at hospitals and clinics. Imagine if water authorities or food producers waited for people to get sick before they took any action to reduce health risks.

    Admittedly, this is a very difficult problem for decision-makers. Rural residential development and urban expansion into fire-prone areas demand that precautions must be taken. However, an attempt to inform and seek consent from the community before taking health and other risks on their behalf would be appreciated. Think of it as a form of social ‘burning-off’.

  2. Max Thomas

    Max Thomas

    May 20, 2018 at 1:10 pm

    P.S. It’s stating the obvious, but at least food and water consumption are discretionary to the extent necessary to avoid immediate health risks, whereas we usually have little choice about the air we breathe.